diff --git a/acceptance/bundle/validate/app_resource_duplicate_name_location/databricks.yml b/acceptance/bundle/validate/app_resource_duplicate_name_location/databricks.yml
new file mode 100644
index 00000000000..7ae4a68fa02
--- /dev/null
+++ b/acceptance/bundle/validate/app_resource_duplicate_name_location/databricks.yml
@@ -0,0 +1,17 @@
+bundle:
+  name: test-bundle
+
+resources:
+  apps:
+    app:
+      name: test-app
+      source_code_path: .
+      resources:
+        - name: job
+          job:
+            id: "1"
+            permission: INVALID
+        - name: job
+          job:
+            id: "2"
+            permission: INVALID
diff --git a/acceptance/bundle/validate/anchor_containers/out.test.toml b/acceptance/bundle/validate/app_resource_duplicate_name_location/out.test.toml
similarity index 100%
rename from acceptance/bundle/validate/anchor_containers/out.test.toml
rename to acceptance/bundle/validate/app_resource_duplicate_name_location/out.test.toml
diff --git a/acceptance/bundle/validate/app_resource_duplicate_name_location/output.txt b/acceptance/bundle/validate/app_resource_duplicate_name_location/output.txt
new file mode 100644
index 00000000000..a8eac9a3ace
--- /dev/null
+++ b/acceptance/bundle/validate/app_resource_duplicate_name_location/output.txt
@@ -0,0 +1,28 @@
+
+>>> [CLI] bundle validate
+Warning: invalid value "INVALID" for enum field. Valid values are [CAN_MANAGE CAN_MANAGE_RUN CAN_VIEW IS_OWNER]
+  at resources.apps.app.resources[0].job.permission
+  in databricks.yml:13:25
+
+Name: test-bundle
+Target: default
+Workspace:
+  User: [USERNAME]
+  Path: /Workspace/Users/[USERNAME]/.bundle/test-bundle/default
+
+Found 1 warning
+
+>>> [CLI] bundle validate -o json
+Warning: invalid value "INVALID" for enum field. Valid values are [CAN_MANAGE CAN_MANAGE_RUN CAN_VIEW IS_OWNER]
+  at resources.apps.app.resources[0].job.permission
+  in databricks.yml:13:25
+
+[
+  {
+    "job": {
+      "id": "2",
+      "permission": "INVALID"
+    },
+    "name": "job"
+  }
+]
diff --git a/acceptance/bundle/validate/app_resource_duplicate_name_location/script b/acceptance/bundle/validate/app_resource_duplicate_name_location/script
new file mode 100644
index 00000000000..3531c01dcef
--- /dev/null
+++ b/acceptance/bundle/validate/app_resource_duplicate_name_location/script
@@ -0,0 +1,5 @@
+# A diagnostic on a field of a duplicated app resource entry points at the first entry when the duplicate's value is the same.
+errcode trace $CLI bundle validate
+
+# The entries are merged by name, the later one wins.
+trace $CLI bundle validate -o json | jq .resources.apps.app.resources
diff --git a/acceptance/bundle/validate/includes/clears_unforced_preset_values/databricks.yml b/acceptance/bundle/validate/includes/clears_unforced_preset_values/databricks.yml
new file mode 100644
index 00000000000..0a6c0479fee
--- /dev/null
+++ b/acceptance/bundle/validate/includes/clears_unforced_preset_values/databricks.yml
@@ -0,0 +1,15 @@
+bundle:
+  name: test-bundle
+
+include:
+  - override.yml
+
+presets:
+  name_prefix: "base-"
+  jobs_max_concurrent_runs: 7
+  artifacts_dynamic_version: true
+
+resources:
+  jobs:
+    j:
+      name: job
diff --git a/acceptance/bundle/validate/complex_variable_default_merge/out.test.toml b/acceptance/bundle/validate/includes/clears_unforced_preset_values/out.test.toml
similarity index 100%
rename from acceptance/bundle/validate/complex_variable_default_merge/out.test.toml
rename to acceptance/bundle/validate/includes/clears_unforced_preset_values/out.test.toml
diff --git a/acceptance/bundle/validate/includes/clears_unforced_preset_values/output.txt b/acceptance/bundle/validate/includes/clears_unforced_preset_values/output.txt
new file mode 100644
index 00000000000..82b92b1e6ad
--- /dev/null
+++ b/acceptance/bundle/validate/includes/clears_unforced_preset_values/output.txt
@@ -0,0 +1,9 @@
+
+>>> [CLI] bundle validate -o json
+{
+  "presets": {},
+  "job": {
+    "name": "job",
+    "max_concurrent_runs": 1
+  }
+}
diff --git a/acceptance/bundle/validate/includes/clears_unforced_preset_values/override.yml b/acceptance/bundle/validate/includes/clears_unforced_preset_values/override.yml
new file mode 100644
index 00000000000..dc413ce0648
--- /dev/null
+++ b/acceptance/bundle/validate/includes/clears_unforced_preset_values/override.yml
@@ -0,0 +1,4 @@
+presets:
+  name_prefix: ""
+  jobs_max_concurrent_runs: 0
+  artifacts_dynamic_version: false
diff --git a/acceptance/bundle/validate/includes/clears_unforced_preset_values/script b/acceptance/bundle/validate/includes/clears_unforced_preset_values/script
new file mode 100644
index 00000000000..c8d6c1aace9
--- /dev/null
+++ b/acceptance/bundle/validate/includes/clears_unforced_preset_values/script
@@ -0,0 +1,2 @@
+# An include can override fields with "", 0 and false.
+trace $CLI bundle validate -o json | jq '{presets, job: (.resources.jobs.j | {name, max_concurrent_runs})}'
diff --git a/acceptance/bundle/validate/include_locations/databricks.yml b/acceptance/bundle/validate/includes/locations/databricks.yml
similarity index 100%
rename from acceptance/bundle/validate/include_locations/databricks.yml
rename to acceptance/bundle/validate/includes/locations/databricks.yml
diff --git a/acceptance/bundle/validate/definitions_yaml_anchors/out.test.toml b/acceptance/bundle/validate/includes/locations/out.test.toml
similarity index 100%
rename from acceptance/bundle/validate/definitions_yaml_anchors/out.test.toml
rename to acceptance/bundle/validate/includes/locations/out.test.toml
diff --git a/acceptance/bundle/validate/include_locations/output.dev.json b/acceptance/bundle/validate/includes/locations/output.dev.json
similarity index 100%
rename from acceptance/bundle/validate/include_locations/output.dev.json
rename to acceptance/bundle/validate/includes/locations/output.dev.json
diff --git a/acceptance/bundle/validate/include_locations/output.prod.json b/acceptance/bundle/validate/includes/locations/output.prod.json
similarity index 100%
rename from acceptance/bundle/validate/include_locations/output.prod.json
rename to acceptance/bundle/validate/includes/locations/output.prod.json
diff --git a/acceptance/bundle/validate/include_locations/output.txt b/acceptance/bundle/validate/includes/locations/output.txt
similarity index 100%
rename from acceptance/bundle/validate/include_locations/output.txt
rename to acceptance/bundle/validate/includes/locations/output.txt
diff --git a/acceptance/bundle/validate/include_locations/override.yml b/acceptance/bundle/validate/includes/locations/override.yml
similarity index 100%
rename from acceptance/bundle/validate/include_locations/override.yml
rename to acceptance/bundle/validate/includes/locations/override.yml
diff --git a/acceptance/bundle/validate/include_locations/resources/job.yml b/acceptance/bundle/validate/includes/locations/resources/job.yml
similarity index 100%
rename from acceptance/bundle/validate/include_locations/resources/job.yml
rename to acceptance/bundle/validate/includes/locations/resources/job.yml
diff --git a/acceptance/bundle/validate/include_locations/script b/acceptance/bundle/validate/includes/locations/script
similarity index 100%
rename from acceptance/bundle/validate/include_locations/script
rename to acceptance/bundle/validate/includes/locations/script
diff --git a/acceptance/bundle/validate/include_locations/src/dev.py b/acceptance/bundle/validate/includes/locations/src/dev.py
similarity index 100%
rename from acceptance/bundle/validate/include_locations/src/dev.py
rename to acceptance/bundle/validate/includes/locations/src/dev.py
diff --git a/acceptance/bundle/validate/include_locations/src/prod.py b/acceptance/bundle/validate/includes/locations/src/prod.py
similarity index 100%
rename from acceptance/bundle/validate/include_locations/src/prod.py
rename to acceptance/bundle/validate/includes/locations/src/prod.py
diff --git a/acceptance/bundle/validate/includes/merge_failure_short_circuits_diagnostics/a.yml b/acceptance/bundle/validate/includes/merge_failure_short_circuits_diagnostics/a.yml
new file mode 100644
index 00000000000..5a6fbc1e893
--- /dev/null
+++ b/acceptance/bundle/validate/includes/merge_failure_short_circuits_diagnostics/a.yml
@@ -0,0 +1,3 @@
+variables:
+  x:
+    default: incompatible-scalar
diff --git a/acceptance/bundle/validate/includes/merge_failure_short_circuits_diagnostics/b.yml b/acceptance/bundle/validate/includes/merge_failure_short_circuits_diagnostics/b.yml
new file mode 100644
index 00000000000..61f0de50e9e
--- /dev/null
+++ b/acceptance/bundle/validate/includes/merge_failure_short_circuits_diagnostics/b.yml
@@ -0,0 +1,2 @@
+bundle:
+  unexpected_after_failure: true
diff --git a/acceptance/bundle/validate/includes/merge_failure_short_circuits_diagnostics/databricks.yml b/acceptance/bundle/validate/includes/merge_failure_short_circuits_diagnostics/databricks.yml
new file mode 100644
index 00000000000..fdd8bfa87b3
--- /dev/null
+++ b/acceptance/bundle/validate/includes/merge_failure_short_circuits_diagnostics/databricks.yml
@@ -0,0 +1,12 @@
+bundle:
+  name: test-bundle
+
+include:
+  - a.yml
+  - b.yml
+
+variables:
+  x:
+    type: complex
+    default:
+      key: value
diff --git a/acceptance/bundle/validate/duplicate_yaml_merge_key/out.test.toml b/acceptance/bundle/validate/includes/merge_failure_short_circuits_diagnostics/out.test.toml
similarity index 100%
rename from acceptance/bundle/validate/duplicate_yaml_merge_key/out.test.toml
rename to acceptance/bundle/validate/includes/merge_failure_short_circuits_diagnostics/out.test.toml
diff --git a/acceptance/bundle/validate/includes/merge_failure_short_circuits_diagnostics/output.txt b/acceptance/bundle/validate/includes/merge_failure_short_circuits_diagnostics/output.txt
new file mode 100644
index 00000000000..f5f6443e809
--- /dev/null
+++ b/acceptance/bundle/validate/includes/merge_failure_short_circuits_diagnostics/output.txt
@@ -0,0 +1,9 @@
+
+>>> [CLI] bundle validate
+Error: cannot merge map with string
+
+Name: test-bundle
+
+Found 1 error
+
+Exit code: 1
diff --git a/acceptance/bundle/validate/includes/merge_failure_short_circuits_diagnostics/script b/acceptance/bundle/validate/includes/merge_failure_short_circuits_diagnostics/script
new file mode 100644
index 00000000000..6f34e8010d2
--- /dev/null
+++ b/acceptance/bundle/validate/includes/merge_failure_short_circuits_diagnostics/script
@@ -0,0 +1,2 @@
+# Includes after one that fails to merge do not report their diagnostics.
+errcode trace $CLI bundle validate
diff --git a/acceptance/bundle/validate/includes/merge_failure_short_circuits_diagnostics/test.toml b/acceptance/bundle/validate/includes/merge_failure_short_circuits_diagnostics/test.toml
new file mode 100644
index 00000000000..b11d0b76cd4
--- /dev/null
+++ b/acceptance/bundle/validate/includes/merge_failure_short_circuits_diagnostics/test.toml
@@ -0,0 +1 @@
+Badness = "The merge error has no location or path, and diagnostics of includes loaded after the failed merge (the unknown field in b.yml) are not reported, although they do not depend on the merge."
diff --git a/acceptance/bundle/validate/nulls/resources_container/databricks.yml b/acceptance/bundle/validate/nulls/resources_container/databricks.yml
new file mode 100644
index 00000000000..339364daf47
--- /dev/null
+++ b/acceptance/bundle/validate/nulls/resources_container/databricks.yml
@@ -0,0 +1,4 @@
+bundle:
+  name: test-bundle
+
+resources: null
diff --git a/acceptance/bundle/validate/include_locations/out.test.toml b/acceptance/bundle/validate/nulls/resources_container/out.test.toml
similarity index 100%
rename from acceptance/bundle/validate/include_locations/out.test.toml
rename to acceptance/bundle/validate/nulls/resources_container/out.test.toml
diff --git a/acceptance/bundle/validate/nulls/resources_container/output.txt b/acceptance/bundle/validate/nulls/resources_container/output.txt
new file mode 100644
index 00000000000..1241151fda5
--- /dev/null
+++ b/acceptance/bundle/validate/nulls/resources_container/output.txt
@@ -0,0 +1,9 @@
+
+>>> [CLI] bundle validate
+Error: expected a map at "resources", found nil
+
+Name: test-bundle
+
+Found 1 error
+
+Exit code: 1
diff --git a/acceptance/bundle/validate/nulls/resources_container/script b/acceptance/bundle/validate/nulls/resources_container/script
new file mode 100644
index 00000000000..253cc3d205d
--- /dev/null
+++ b/acceptance/bundle/validate/nulls/resources_container/script
@@ -0,0 +1,2 @@
+# resources: null is rejected.
+errcode trace $CLI bundle validate
diff --git a/acceptance/bundle/validate/nulls/resources_container/test.toml b/acceptance/bundle/validate/nulls/resources_container/test.toml
new file mode 100644
index 00000000000..022e0f2c7e9
--- /dev/null
+++ b/acceptance/bundle/validate/nulls/resources_container/test.toml
@@ -0,0 +1 @@
+Badness = 'An empty (null) resources section is an error without a location, while empty targets, variables or sync sections are accepted.'
diff --git a/acceptance/bundle/validate/nulls/schedule_default_materialization/databricks.yml b/acceptance/bundle/validate/nulls/schedule_default_materialization/databricks.yml
new file mode 100644
index 00000000000..d68996de3ce
--- /dev/null
+++ b/acceptance/bundle/validate/nulls/schedule_default_materialization/databricks.yml
@@ -0,0 +1,8 @@
+bundle:
+  name: test-bundle
+
+resources:
+  jobs:
+    j:
+      name: test
+      schedule: null
diff --git a/acceptance/bundle/validate/target_variable_full_def_merge_key/out.test.toml b/acceptance/bundle/validate/nulls/schedule_default_materialization/out.test.toml
similarity index 100%
rename from acceptance/bundle/validate/target_variable_full_def_merge_key/out.test.toml
rename to acceptance/bundle/validate/nulls/schedule_default_materialization/out.test.toml
diff --git a/acceptance/bundle/validate/nulls/schedule_default_materialization/output.txt b/acceptance/bundle/validate/nulls/schedule_default_materialization/output.txt
new file mode 100644
index 00000000000..8cc844569f5
--- /dev/null
+++ b/acceptance/bundle/validate/nulls/schedule_default_materialization/output.txt
@@ -0,0 +1,13 @@
+
+>>> [CLI] bundle validate -o json
+Warning: required field "quartz_cron_expression" is not set
+  at resources.jobs.j.schedule
+  in databricks.yml:8:17
+
+Warning: required field "timezone_id" is not set
+  at resources.jobs.j.schedule
+  in databricks.yml:8:17
+
+{
+  "schedule": null
+}
diff --git a/acceptance/bundle/validate/nulls/schedule_default_materialization/script b/acceptance/bundle/validate/nulls/schedule_default_materialization/script
new file mode 100644
index 00000000000..0c5e31164ff
--- /dev/null
+++ b/acceptance/bundle/validate/nulls/schedule_default_materialization/script
@@ -0,0 +1,2 @@
+# Defaults are not applied under an explicitly null block (schedule stays null).
+trace $CLI bundle validate -o json | jq '.resources.jobs.j | {schedule}'
diff --git a/acceptance/bundle/validate/nulls/schedule_default_materialization/test.toml b/acceptance/bundle/validate/nulls/schedule_default_materialization/test.toml
new file mode 100644
index 00000000000..68e81befdb7
--- /dev/null
+++ b/acceptance/bundle/validate/nulls/schedule_default_materialization/test.toml
@@ -0,0 +1 @@
+Badness = 'An explicitly null schedule is reported as missing its required fields.'
diff --git a/acceptance/bundle/validate/references/resolved_invalid_map_value/databricks.yml b/acceptance/bundle/validate/references/resolved_invalid_map_value/databricks.yml
new file mode 100644
index 00000000000..3fffd4ad478
--- /dev/null
+++ b/acceptance/bundle/validate/references/resolved_invalid_map_value/databricks.yml
@@ -0,0 +1,16 @@
+bundle:
+  name: test-bundle
+
+variables:
+  bad:
+    type: complex
+    default:
+      x: 1
+
+resources:
+  jobs:
+    j:
+      name: test
+      tags:
+        "bad.key[0]": ${var.bad}
+        good: ok
diff --git a/acceptance/bundle/validate/target_variable_merge_key_precedence/out.test.toml b/acceptance/bundle/validate/references/resolved_invalid_map_value/out.test.toml
similarity index 100%
rename from acceptance/bundle/validate/target_variable_merge_key_precedence/out.test.toml
rename to acceptance/bundle/validate/references/resolved_invalid_map_value/out.test.toml
diff --git a/acceptance/bundle/validate/references/resolved_invalid_map_value/output.txt b/acceptance/bundle/validate/references/resolved_invalid_map_value/output.txt
new file mode 100644
index 00000000000..07bfe6c7450
--- /dev/null
+++ b/acceptance/bundle/validate/references/resolved_invalid_map_value/output.txt
@@ -0,0 +1,9 @@
+
+>>> [CLI] bundle validate -o json
+Warning: expected string, found map
+  at resources.jobs.j.tags['bad.key[0]']
+  in databricks.yml:15:23
+
+{
+  "good": "ok"
+}
diff --git a/acceptance/bundle/validate/references/resolved_invalid_map_value/script b/acceptance/bundle/validate/references/resolved_invalid_map_value/script
new file mode 100644
index 00000000000..835edef52e9
--- /dev/null
+++ b/acceptance/bundle/validate/references/resolved_invalid_map_value/script
@@ -0,0 +1,2 @@
+# A map value whose reference resolves to the wrong type is dropped, with a warning at its path.
+trace $CLI bundle validate -o json | jq .resources.jobs.j.tags
diff --git a/acceptance/bundle/validate/references/resolved_invalid_sequence_item/databricks.yml b/acceptance/bundle/validate/references/resolved_invalid_sequence_item/databricks.yml
new file mode 100644
index 00000000000..90dd5f6d362
--- /dev/null
+++ b/acceptance/bundle/validate/references/resolved_invalid_sequence_item/databricks.yml
@@ -0,0 +1,15 @@
+bundle:
+  name: test-bundle
+
+variables:
+  bad:
+    type: complex
+    default:
+      x: 1
+
+resources:
+  jobs:
+    j:
+      name: test
+      email_notifications:
+        on_failure: ["${var.bad}", "ok@example.test"]
diff --git a/acceptance/bundle/validate/target_variable_shorthand_alias/out.test.toml b/acceptance/bundle/validate/references/resolved_invalid_sequence_item/out.test.toml
similarity index 100%
rename from acceptance/bundle/validate/target_variable_shorthand_alias/out.test.toml
rename to acceptance/bundle/validate/references/resolved_invalid_sequence_item/out.test.toml
diff --git a/acceptance/bundle/validate/references/resolved_invalid_sequence_item/output.txt b/acceptance/bundle/validate/references/resolved_invalid_sequence_item/output.txt
new file mode 100644
index 00000000000..03952e879af
--- /dev/null
+++ b/acceptance/bundle/validate/references/resolved_invalid_sequence_item/output.txt
@@ -0,0 +1,11 @@
+
+>>> [CLI] bundle validate -o json
+Warning: expected string, found map
+  at resources.jobs.j.email_notifications.on_failure[0]
+  in databricks.yml:15:22
+
+{
+  "on_failure": [
+    "ok@example.test"
+  ]
+}
diff --git a/acceptance/bundle/validate/references/resolved_invalid_sequence_item/script b/acceptance/bundle/validate/references/resolved_invalid_sequence_item/script
new file mode 100644
index 00000000000..61ba88b4d75
--- /dev/null
+++ b/acceptance/bundle/validate/references/resolved_invalid_sequence_item/script
@@ -0,0 +1,2 @@
+# A list element whose reference resolves to the wrong type is dropped, with a warning at its path.
+trace $CLI bundle validate -o json | jq .resources.jobs.j.email_notifications
diff --git a/acceptance/bundle/validate/references/to_omitted_struct_defaults/databricks.yml b/acceptance/bundle/validate/references/to_omitted_struct_defaults/databricks.yml
new file mode 100644
index 00000000000..b3d428b5e16
--- /dev/null
+++ b/acceptance/bundle/validate/references/to_omitted_struct_defaults/databricks.yml
@@ -0,0 +1,7 @@
+bundle:
+  name: test-bundle
+
+variables:
+  git_info:
+    type: complex
+    default: ${bundle.git}
diff --git a/acceptance/bundle/validate/variable_overrides_file_complex_path/out.test.toml b/acceptance/bundle/validate/references/to_omitted_struct_defaults/out.test.toml
similarity index 100%
rename from acceptance/bundle/validate/variable_overrides_file_complex_path/out.test.toml
rename to acceptance/bundle/validate/references/to_omitted_struct_defaults/out.test.toml
diff --git a/acceptance/bundle/validate/references/to_omitted_struct_defaults/output.txt b/acceptance/bundle/validate/references/to_omitted_struct_defaults/output.txt
new file mode 100644
index 00000000000..479ce92fe43
--- /dev/null
+++ b/acceptance/bundle/validate/references/to_omitted_struct_defaults/output.txt
@@ -0,0 +1,19 @@
+
+>>> [CLI] bundle validate -o json
+{
+  "default": {
+    "actual_branch": "",
+    "branch": "",
+    "bundle_root_path": ".",
+    "commit": "",
+    "origin_url": ""
+  },
+  "type": "complex",
+  "value": {
+    "actual_branch": "",
+    "branch": "",
+    "bundle_root_path": ".",
+    "commit": "",
+    "origin_url": ""
+  }
+}
diff --git a/acceptance/bundle/validate/references/to_omitted_struct_defaults/script b/acceptance/bundle/validate/references/to_omitted_struct_defaults/script
new file mode 100644
index 00000000000..cb09a7b5bec
--- /dev/null
+++ b/acceptance/bundle/validate/references/to_omitted_struct_defaults/script
@@ -0,0 +1,3 @@
+# A reference to a struct that is not set in the configuration (here outside a git repository)
+# resolves to the struct with its fields filled in, as empty values.
+trace $CLI bundle validate -o json | jq .variables.git_info
diff --git a/acceptance/bundle/validate/targets/inherited_from_root_merge/databricks.yml b/acceptance/bundle/validate/targets/inherited_from_root_merge/databricks.yml
new file mode 100644
index 00000000000..e5a45a569c9
--- /dev/null
+++ b/acceptance/bundle/validate/targets/inherited_from_root_merge/databricks.yml
@@ -0,0 +1,15 @@
+bundle:
+  name: test-bundle
+
+variables:
+  x:
+    default: base
+
+definitions:
+  root_defaults: &root_defaults
+    targets:
+      dev:
+        variables:
+          x: overridden
+
+<<: *root_defaults
diff --git a/acceptance/bundle/validate/yaml_anchor_cycle_nested/out.test.toml b/acceptance/bundle/validate/targets/inherited_from_root_merge/out.test.toml
similarity index 100%
rename from acceptance/bundle/validate/yaml_anchor_cycle_nested/out.test.toml
rename to acceptance/bundle/validate/targets/inherited_from_root_merge/out.test.toml
diff --git a/acceptance/bundle/validate/targets/inherited_from_root_merge/output.txt b/acceptance/bundle/validate/targets/inherited_from_root_merge/output.txt
new file mode 100644
index 00000000000..d3be1ebf0eb
--- /dev/null
+++ b/acceptance/bundle/validate/targets/inherited_from_root_merge/output.txt
@@ -0,0 +1,6 @@
+
+>>> [CLI] bundle validate -t dev -o json
+{
+  "default": "overridden",
+  "value": "overridden"
+}
diff --git a/acceptance/bundle/validate/targets/inherited_from_root_merge/script b/acceptance/bundle/validate/targets/inherited_from_root_merge/script
new file mode 100644
index 00000000000..b51a0e30bfe
--- /dev/null
+++ b/acceptance/bundle/validate/targets/inherited_from_root_merge/script
@@ -0,0 +1,2 @@
+# Target variable shorthands in a targets section inherited through a root merge key are applied.
+trace $CLI bundle validate -t dev -o json | jq .variables.x
diff --git a/acceptance/bundle/validate/targets/scalar_rewrite_diagnostic/databricks.yml b/acceptance/bundle/validate/targets/scalar_rewrite_diagnostic/databricks.yml
new file mode 100644
index 00000000000..2583829e912
--- /dev/null
+++ b/acceptance/bundle/validate/targets/scalar_rewrite_diagnostic/databricks.yml
@@ -0,0 +1,4 @@
+bundle:
+  name: test-bundle
+
+targets: false
diff --git a/acceptance/bundle/validate/targets/scalar_rewrite_diagnostic/out.test.toml b/acceptance/bundle/validate/targets/scalar_rewrite_diagnostic/out.test.toml
new file mode 100644
index 00000000000..a927a5fbc06
--- /dev/null
+++ b/acceptance/bundle/validate/targets/scalar_rewrite_diagnostic/out.test.toml
@@ -0,0 +1,2 @@
+Cloud = false
+EnvMatrix.DMS = ["", "true"]
diff --git a/acceptance/bundle/validate/targets/scalar_rewrite_diagnostic/output.txt b/acceptance/bundle/validate/targets/scalar_rewrite_diagnostic/output.txt
new file mode 100644
index 00000000000..8020d180559
--- /dev/null
+++ b/acceptance/bundle/validate/targets/scalar_rewrite_diagnostic/output.txt
@@ -0,0 +1,8 @@
+
+>>> [CLI] bundle validate
+Error: failed to rewrite [TEST_TMP_DIR]/databricks.yml: expected a map or sequence, found bool
+
+
+Found 1 error
+
+Exit code: 1
diff --git a/acceptance/bundle/validate/targets/scalar_rewrite_diagnostic/script b/acceptance/bundle/validate/targets/scalar_rewrite_diagnostic/script
new file mode 100644
index 00000000000..4f218738be7
--- /dev/null
+++ b/acceptance/bundle/validate/targets/scalar_rewrite_diagnostic/script
@@ -0,0 +1,2 @@
+# A scalar targets section is an error.
+errcode trace $CLI bundle validate
diff --git a/acceptance/bundle/validate/targets/scalar_rewrite_diagnostic/test.toml b/acceptance/bundle/validate/targets/scalar_rewrite_diagnostic/test.toml
new file mode 100644
index 00000000000..b1bb8151234
--- /dev/null
+++ b/acceptance/bundle/validate/targets/scalar_rewrite_diagnostic/test.toml
@@ -0,0 +1 @@
+Badness = 'The error names an internal step ("failed to rewrite") and has no location, instead of reporting a type error at targets.'
diff --git a/acceptance/bundle/validate/targets/test.toml b/acceptance/bundle/validate/targets/test.toml
new file mode 100644
index 00000000000..e9cede5e28a
--- /dev/null
+++ b/acceptance/bundle/validate/targets/test.toml
@@ -0,0 +1,4 @@
+# Errors for invalid YAML print the full path of the file; normalize Windows separators.
+[[Repls]]
+Old = '\\'
+New = '/'
diff --git a/acceptance/bundle/validate/complex_variable_default_merge/a.yml b/acceptance/bundle/validate/variables/complex_default_merge/a.yml
similarity index 100%
rename from acceptance/bundle/validate/complex_variable_default_merge/a.yml
rename to acceptance/bundle/validate/variables/complex_default_merge/a.yml
diff --git a/acceptance/bundle/validate/complex_variable_default_merge/b.yml b/acceptance/bundle/validate/variables/complex_default_merge/b.yml
similarity index 100%
rename from acceptance/bundle/validate/complex_variable_default_merge/b.yml
rename to acceptance/bundle/validate/variables/complex_default_merge/b.yml
diff --git a/acceptance/bundle/validate/complex_variable_default_merge/databricks.yml b/acceptance/bundle/validate/variables/complex_default_merge/databricks.yml
similarity index 100%
rename from acceptance/bundle/validate/complex_variable_default_merge/databricks.yml
rename to acceptance/bundle/validate/variables/complex_default_merge/databricks.yml
diff --git a/acceptance/bundle/validate/variables/complex_default_merge/out.test.toml b/acceptance/bundle/validate/variables/complex_default_merge/out.test.toml
new file mode 100644
index 00000000000..a927a5fbc06
--- /dev/null
+++ b/acceptance/bundle/validate/variables/complex_default_merge/out.test.toml
@@ -0,0 +1,2 @@
+Cloud = false
+EnvMatrix.DMS = ["", "true"]
diff --git a/acceptance/bundle/validate/complex_variable_default_merge/output.txt b/acceptance/bundle/validate/variables/complex_default_merge/output.txt
similarity index 100%
rename from acceptance/bundle/validate/complex_variable_default_merge/output.txt
rename to acceptance/bundle/validate/variables/complex_default_merge/output.txt
diff --git a/acceptance/bundle/validate/complex_variable_default_merge/script b/acceptance/bundle/validate/variables/complex_default_merge/script
similarity index 100%
rename from acceptance/bundle/validate/complex_variable_default_merge/script
rename to acceptance/bundle/validate/variables/complex_default_merge/script
diff --git a/acceptance/bundle/validate/variables/complex_default_nested_timestamp/databricks.yml b/acceptance/bundle/validate/variables/complex_default_nested_timestamp/databricks.yml
new file mode 100644
index 00000000000..43221f5f33a
--- /dev/null
+++ b/acceptance/bundle/validate/variables/complex_default_nested_timestamp/databricks.yml
@@ -0,0 +1,8 @@
+bundle:
+  name: test-bundle
+
+variables:
+  payload:
+    type: complex
+    default:
+      created: 2020-01-02
diff --git a/acceptance/bundle/validate/variables/complex_default_nested_timestamp/out.test.toml b/acceptance/bundle/validate/variables/complex_default_nested_timestamp/out.test.toml
new file mode 100644
index 00000000000..a927a5fbc06
--- /dev/null
+++ b/acceptance/bundle/validate/variables/complex_default_nested_timestamp/out.test.toml
@@ -0,0 +1,2 @@
+Cloud = false
+EnvMatrix.DMS = ["", "true"]
diff --git a/acceptance/bundle/validate/variables/complex_default_nested_timestamp/output.txt b/acceptance/bundle/validate/variables/complex_default_nested_timestamp/output.txt
new file mode 100644
index 00000000000..3c236fb1c2b
--- /dev/null
+++ b/acceptance/bundle/validate/variables/complex_default_nested_timestamp/output.txt
@@ -0,0 +1,10 @@
+
+>>> [CLI] bundle validate
+Warn: unable to convert typed configuration to dynamic configuration: cannot convert struct field to dynamic type "time": src=time.Date(2020, time.January, 2, 0, 0, 0, 0, time.UTC) ref=time.Date(2020, time.January, 2, 0, 0, 0, 0, time.UTC)
+Error: exit error: cannot convert struct field to dynamic type "time": src=time.Date(2020, time.January, 2, 0, 0, 0, 0, time.UTC) ref=time.Date(2020, time.January, 2, 0, 0, 0, 0, time.UTC)
+
+Name: test-bundle
+
+Found 1 error
+
+Exit code: 1
diff --git a/acceptance/bundle/validate/variables/complex_default_nested_timestamp/script b/acceptance/bundle/validate/variables/complex_default_nested_timestamp/script
new file mode 100644
index 00000000000..e4d20dafe80
--- /dev/null
+++ b/acceptance/bundle/validate/variables/complex_default_nested_timestamp/script
@@ -0,0 +1,2 @@
+# A timestamp nested inside a complex variable default.
+errcode trace $CLI bundle validate
diff --git a/acceptance/bundle/validate/variables/complex_default_nested_timestamp/test.toml b/acceptance/bundle/validate/variables/complex_default_nested_timestamp/test.toml
new file mode 100644
index 00000000000..b1b00a5e46a
--- /dev/null
+++ b/acceptance/bundle/validate/variables/complex_default_nested_timestamp/test.toml
@@ -0,0 +1 @@
+Badness = "A valid config fails with an internal conversion error: the nested timestamp cannot be converted back to the dynamic configuration."
diff --git a/acceptance/bundle/validate/variables/complex_unknown_field_location/databricks.yml b/acceptance/bundle/validate/variables/complex_unknown_field_location/databricks.yml
new file mode 100644
index 00000000000..a337abdcff1
--- /dev/null
+++ b/acceptance/bundle/validate/variables/complex_unknown_field_location/databricks.yml
@@ -0,0 +1,13 @@
+bundle:
+  name: test-bundle
+
+variables:
+  job_config:
+    type: complex
+    default:
+      name: test
+      misspelled_field: value
+
+resources:
+  jobs:
+    j: ${var.job_config}
diff --git a/acceptance/bundle/validate/variables/complex_unknown_field_location/out.test.toml b/acceptance/bundle/validate/variables/complex_unknown_field_location/out.test.toml
new file mode 100644
index 00000000000..a927a5fbc06
--- /dev/null
+++ b/acceptance/bundle/validate/variables/complex_unknown_field_location/out.test.toml
@@ -0,0 +1,2 @@
+Cloud = false
+EnvMatrix.DMS = ["", "true"]
diff --git a/acceptance/bundle/validate/variables/complex_unknown_field_location/output.txt b/acceptance/bundle/validate/variables/complex_unknown_field_location/output.txt
new file mode 100644
index 00000000000..118399cba34
--- /dev/null
+++ b/acceptance/bundle/validate/variables/complex_unknown_field_location/output.txt
@@ -0,0 +1,13 @@
+
+>>> [CLI] bundle validate
+Warning: unknown field: misspelled_field
+  at resources.jobs.j
+  in databricks.yml:9:7
+
+Name: test-bundle
+Target: default
+Workspace:
+  User: [USERNAME]
+  Path: /Workspace/Users/[USERNAME]/.bundle/test-bundle/default
+
+Found 1 warning
diff --git a/acceptance/bundle/validate/variables/complex_unknown_field_location/script b/acceptance/bundle/validate/variables/complex_unknown_field_location/script
new file mode 100644
index 00000000000..4b8218079e8
--- /dev/null
+++ b/acceptance/bundle/validate/variables/complex_unknown_field_location/script
@@ -0,0 +1,2 @@
+# An unknown field inside a complex variable used as a whole resource keeps the location of its key.
+errcode trace $CLI bundle validate
diff --git a/acceptance/bundle/validate/variable_overrides_file_complex_path/databricks.yml b/acceptance/bundle/validate/variables/overrides_file_complex_path/databricks.yml
similarity index 100%
rename from acceptance/bundle/validate/variable_overrides_file_complex_path/databricks.yml
rename to acceptance/bundle/validate/variables/overrides_file_complex_path/databricks.yml
diff --git a/acceptance/bundle/validate/variables/overrides_file_complex_path/out.test.toml b/acceptance/bundle/validate/variables/overrides_file_complex_path/out.test.toml
new file mode 100644
index 00000000000..a927a5fbc06
--- /dev/null
+++ b/acceptance/bundle/validate/variables/overrides_file_complex_path/out.test.toml
@@ -0,0 +1,2 @@
+Cloud = false
+EnvMatrix.DMS = ["", "true"]
diff --git a/acceptance/bundle/validate/variable_overrides_file_complex_path/output.txt b/acceptance/bundle/validate/variables/overrides_file_complex_path/output.txt
similarity index 100%
rename from acceptance/bundle/validate/variable_overrides_file_complex_path/output.txt
rename to acceptance/bundle/validate/variables/overrides_file_complex_path/output.txt
diff --git a/acceptance/bundle/validate/variable_overrides_file_complex_path/script b/acceptance/bundle/validate/variables/overrides_file_complex_path/script
similarity index 100%
rename from acceptance/bundle/validate/variable_overrides_file_complex_path/script
rename to acceptance/bundle/validate/variables/overrides_file_complex_path/script
diff --git a/acceptance/bundle/validate/variable_overrides_file_complex_path/src/lib.whl b/acceptance/bundle/validate/variables/overrides_file_complex_path/src/lib.whl
similarity index 100%
rename from acceptance/bundle/validate/variable_overrides_file_complex_path/src/lib.whl
rename to acceptance/bundle/validate/variables/overrides_file_complex_path/src/lib.whl
diff --git a/acceptance/bundle/validate/variable_overrides_file_complex_path/src/main.py b/acceptance/bundle/validate/variables/overrides_file_complex_path/src/main.py
similarity index 100%
rename from acceptance/bundle/validate/variable_overrides_file_complex_path/src/main.py
rename to acceptance/bundle/validate/variables/overrides_file_complex_path/src/main.py
diff --git a/acceptance/bundle/validate/variable_overrides_file_complex_path/test.toml b/acceptance/bundle/validate/variables/overrides_file_complex_path/test.toml
similarity index 100%
rename from acceptance/bundle/validate/variable_overrides_file_complex_path/test.toml
rename to acceptance/bundle/validate/variables/overrides_file_complex_path/test.toml
diff --git a/acceptance/bundle/validate/variable_overrides_file_complex_path/variable-overrides.json b/acceptance/bundle/validate/variables/overrides_file_complex_path/variable-overrides.json
similarity index 100%
rename from acceptance/bundle/validate/variable_overrides_file_complex_path/variable-overrides.json
rename to acceptance/bundle/validate/variables/overrides_file_complex_path/variable-overrides.json
diff --git a/acceptance/bundle/validate/variables/target_inherited_from_target_merge/databricks.yml b/acceptance/bundle/validate/variables/target_inherited_from_target_merge/databricks.yml
new file mode 100644
index 00000000000..497c570326c
--- /dev/null
+++ b/acceptance/bundle/validate/variables/target_inherited_from_target_merge/databricks.yml
@@ -0,0 +1,15 @@
+bundle:
+  name: test-bundle
+
+variables:
+  x:
+    default: base
+
+definitions:
+  target_defaults: &target_defaults
+    variables:
+      x: overridden
+
+targets:
+  dev:
+    <<: *target_defaults
diff --git a/acceptance/bundle/validate/variables/target_inherited_from_target_merge/out.test.toml b/acceptance/bundle/validate/variables/target_inherited_from_target_merge/out.test.toml
new file mode 100644
index 00000000000..a927a5fbc06
--- /dev/null
+++ b/acceptance/bundle/validate/variables/target_inherited_from_target_merge/out.test.toml
@@ -0,0 +1,2 @@
+Cloud = false
+EnvMatrix.DMS = ["", "true"]
diff --git a/acceptance/bundle/validate/variables/target_inherited_from_target_merge/output.txt b/acceptance/bundle/validate/variables/target_inherited_from_target_merge/output.txt
new file mode 100644
index 00000000000..d3be1ebf0eb
--- /dev/null
+++ b/acceptance/bundle/validate/variables/target_inherited_from_target_merge/output.txt
@@ -0,0 +1,6 @@
+
+>>> [CLI] bundle validate -t dev -o json
+{
+  "default": "overridden",
+  "value": "overridden"
+}
diff --git a/acceptance/bundle/validate/variables/target_inherited_from_target_merge/script b/acceptance/bundle/validate/variables/target_inherited_from_target_merge/script
new file mode 100644
index 00000000000..4339582a088
--- /dev/null
+++ b/acceptance/bundle/validate/variables/target_inherited_from_target_merge/script
@@ -0,0 +1,2 @@
+# Target variable shorthands inherited through a merge key on the target are applied.
+trace $CLI bundle validate -t dev -o json | jq .variables.x
diff --git a/acceptance/bundle/validate/variables/target_timestamp_shorthand/databricks.yml b/acceptance/bundle/validate/variables/target_timestamp_shorthand/databricks.yml
new file mode 100644
index 00000000000..84eeb5183bd
--- /dev/null
+++ b/acceptance/bundle/validate/variables/target_timestamp_shorthand/databricks.yml
@@ -0,0 +1,11 @@
+bundle:
+  name: test-bundle
+
+variables:
+  x:
+    default: base
+
+targets:
+  dev:
+    variables:
+      x: 2020-01-02
diff --git a/acceptance/bundle/validate/variables/target_timestamp_shorthand/out.test.toml b/acceptance/bundle/validate/variables/target_timestamp_shorthand/out.test.toml
new file mode 100644
index 00000000000..a927a5fbc06
--- /dev/null
+++ b/acceptance/bundle/validate/variables/target_timestamp_shorthand/out.test.toml
@@ -0,0 +1,2 @@
+Cloud = false
+EnvMatrix.DMS = ["", "true"]
diff --git a/acceptance/bundle/validate/variables/target_timestamp_shorthand/output.txt b/acceptance/bundle/validate/variables/target_timestamp_shorthand/output.txt
new file mode 100644
index 00000000000..07eae4cbd80
--- /dev/null
+++ b/acceptance/bundle/validate/variables/target_timestamp_shorthand/output.txt
@@ -0,0 +1,10 @@
+
+>>> [CLI] bundle validate -t dev -o json
+Warning: expected map, found time
+  at targets.dev.variables.x
+  in databricks.yml:11:10
+
+{
+  "default": "base",
+  "value": "base"
+}
diff --git a/acceptance/bundle/validate/variables/target_timestamp_shorthand/script b/acceptance/bundle/validate/variables/target_timestamp_shorthand/script
new file mode 100644
index 00000000000..e5418dbd3df
--- /dev/null
+++ b/acceptance/bundle/validate/variables/target_timestamp_shorthand/script
@@ -0,0 +1,2 @@
+# A timestamp as a target variable shorthand.
+trace $CLI bundle validate -t dev -o json | jq .variables.x
diff --git a/acceptance/bundle/validate/variables/target_timestamp_shorthand/test.toml b/acceptance/bundle/validate/variables/target_timestamp_shorthand/test.toml
new file mode 100644
index 00000000000..83f0c9957ac
--- /dev/null
+++ b/acceptance/bundle/validate/variables/target_timestamp_shorthand/test.toml
@@ -0,0 +1 @@
+Badness = 'The timestamp shorthand is dropped with "expected map, found time" instead of being used as the default.'
diff --git a/acceptance/bundle/validate/yaml_anchors/alias_mutates_complex_default/databricks.yml b/acceptance/bundle/validate/yaml_anchors/alias_mutates_complex_default/databricks.yml
new file mode 100644
index 00000000000..87f970afec3
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_anchors/alias_mutates_complex_default/databricks.yml
@@ -0,0 +1,14 @@
+bundle:
+  name: test-bundle
+
+variables:
+  x:
+    default: base
+  payload:
+    type: complex
+    default: &overrides
+      x: overridden
+
+targets:
+  dev:
+    variables: *overrides
diff --git a/acceptance/bundle/validate/yaml_anchors/alias_mutates_complex_default/out.test.toml b/acceptance/bundle/validate/yaml_anchors/alias_mutates_complex_default/out.test.toml
new file mode 100644
index 00000000000..a927a5fbc06
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_anchors/alias_mutates_complex_default/out.test.toml
@@ -0,0 +1,2 @@
+Cloud = false
+EnvMatrix.DMS = ["", "true"]
diff --git a/acceptance/bundle/validate/yaml_anchors/alias_mutates_complex_default/output.txt b/acceptance/bundle/validate/yaml_anchors/alias_mutates_complex_default/output.txt
new file mode 100644
index 00000000000..e324cc30cf1
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_anchors/alias_mutates_complex_default/output.txt
@@ -0,0 +1,17 @@
+
+>>> [CLI] bundle validate -t dev -o json
+{
+  "x": {
+    "default": "overridden",
+    "value": "overridden"
+  },
+  "payload": {
+    "default": {
+      "x": "overridden"
+    },
+    "type": "complex",
+    "value": {
+      "x": "overridden"
+    }
+  }
+}
diff --git a/acceptance/bundle/validate/yaml_anchors/alias_mutates_complex_default/script b/acceptance/bundle/validate/yaml_anchors/alias_mutates_complex_default/script
new file mode 100644
index 00000000000..56f3e365324
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_anchors/alias_mutates_complex_default/script
@@ -0,0 +1,2 @@
+# Target variables given as an alias of a complex default do not change that default.
+trace $CLI bundle validate -t dev -o json | jq '.variables | {x, payload}'
diff --git a/acceptance/bundle/validate/anchor_containers/databricks.yml b/acceptance/bundle/validate/yaml_anchors/containers/databricks.yml
similarity index 100%
rename from acceptance/bundle/validate/anchor_containers/databricks.yml
rename to acceptance/bundle/validate/yaml_anchors/containers/databricks.yml
diff --git a/acceptance/bundle/validate/yaml_anchors/containers/out.test.toml b/acceptance/bundle/validate/yaml_anchors/containers/out.test.toml
new file mode 100644
index 00000000000..a927a5fbc06
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_anchors/containers/out.test.toml
@@ -0,0 +1,2 @@
+Cloud = false
+EnvMatrix.DMS = ["", "true"]
diff --git a/acceptance/bundle/validate/anchor_containers/output.txt b/acceptance/bundle/validate/yaml_anchors/containers/output.txt
similarity index 100%
rename from acceptance/bundle/validate/anchor_containers/output.txt
rename to acceptance/bundle/validate/yaml_anchors/containers/output.txt
diff --git a/acceptance/bundle/validate/anchor_containers/script b/acceptance/bundle/validate/yaml_anchors/containers/script
similarity index 100%
rename from acceptance/bundle/validate/anchor_containers/script
rename to acceptance/bundle/validate/yaml_anchors/containers/script
diff --git a/acceptance/bundle/validate/yaml_anchor_cycle_nested/databricks.yml b/acceptance/bundle/validate/yaml_anchors/cycle_nested/databricks.yml
similarity index 100%
rename from acceptance/bundle/validate/yaml_anchor_cycle_nested/databricks.yml
rename to acceptance/bundle/validate/yaml_anchors/cycle_nested/databricks.yml
diff --git a/acceptance/bundle/validate/yaml_anchors/cycle_nested/out.test.toml b/acceptance/bundle/validate/yaml_anchors/cycle_nested/out.test.toml
new file mode 100644
index 00000000000..a927a5fbc06
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_anchors/cycle_nested/out.test.toml
@@ -0,0 +1,2 @@
+Cloud = false
+EnvMatrix.DMS = ["", "true"]
diff --git a/acceptance/bundle/validate/yaml_anchor_cycle_nested/output.txt b/acceptance/bundle/validate/yaml_anchors/cycle_nested/output.txt
similarity index 100%
rename from acceptance/bundle/validate/yaml_anchor_cycle_nested/output.txt
rename to acceptance/bundle/validate/yaml_anchors/cycle_nested/output.txt
diff --git a/acceptance/bundle/validate/yaml_anchor_cycle_nested/script b/acceptance/bundle/validate/yaml_anchors/cycle_nested/script
similarity index 100%
rename from acceptance/bundle/validate/yaml_anchor_cycle_nested/script
rename to acceptance/bundle/validate/yaml_anchors/cycle_nested/script
diff --git a/acceptance/bundle/validate/yaml_anchor_cycle_nested/test.toml b/acceptance/bundle/validate/yaml_anchors/cycle_nested/test.toml
similarity index 100%
rename from acceptance/bundle/validate/yaml_anchor_cycle_nested/test.toml
rename to acceptance/bundle/validate/yaml_anchors/cycle_nested/test.toml
diff --git a/acceptance/bundle/validate/definitions_yaml_anchors/databricks.yml b/acceptance/bundle/validate/yaml_anchors/definitions/databricks.yml
similarity index 100%
rename from acceptance/bundle/validate/definitions_yaml_anchors/databricks.yml
rename to acceptance/bundle/validate/yaml_anchors/definitions/databricks.yml
diff --git a/acceptance/bundle/validate/yaml_anchors/definitions/out.test.toml b/acceptance/bundle/validate/yaml_anchors/definitions/out.test.toml
new file mode 100644
index 00000000000..a927a5fbc06
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_anchors/definitions/out.test.toml
@@ -0,0 +1,2 @@
+Cloud = false
+EnvMatrix.DMS = ["", "true"]
diff --git a/acceptance/bundle/validate/definitions_yaml_anchors/output.txt b/acceptance/bundle/validate/yaml_anchors/definitions/output.txt
similarity index 100%
rename from acceptance/bundle/validate/definitions_yaml_anchors/output.txt
rename to acceptance/bundle/validate/yaml_anchors/definitions/output.txt
diff --git a/acceptance/bundle/validate/definitions_yaml_anchors/script b/acceptance/bundle/validate/yaml_anchors/definitions/script
similarity index 100%
rename from acceptance/bundle/validate/definitions_yaml_anchors/script
rename to acceptance/bundle/validate/yaml_anchors/definitions/script
diff --git a/acceptance/bundle/validate/duplicate_yaml_merge_key/databricks.yml b/acceptance/bundle/validate/yaml_anchors/duplicate_merge_key_in_cluster/databricks.yml
similarity index 100%
rename from acceptance/bundle/validate/duplicate_yaml_merge_key/databricks.yml
rename to acceptance/bundle/validate/yaml_anchors/duplicate_merge_key_in_cluster/databricks.yml
diff --git a/acceptance/bundle/validate/yaml_anchors/duplicate_merge_key_in_cluster/out.test.toml b/acceptance/bundle/validate/yaml_anchors/duplicate_merge_key_in_cluster/out.test.toml
new file mode 100644
index 00000000000..a927a5fbc06
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_anchors/duplicate_merge_key_in_cluster/out.test.toml
@@ -0,0 +1,2 @@
+Cloud = false
+EnvMatrix.DMS = ["", "true"]
diff --git a/acceptance/bundle/validate/duplicate_yaml_merge_key/output.txt b/acceptance/bundle/validate/yaml_anchors/duplicate_merge_key_in_cluster/output.txt
similarity index 100%
rename from acceptance/bundle/validate/duplicate_yaml_merge_key/output.txt
rename to acceptance/bundle/validate/yaml_anchors/duplicate_merge_key_in_cluster/output.txt
diff --git a/acceptance/bundle/validate/duplicate_yaml_merge_key/script b/acceptance/bundle/validate/yaml_anchors/duplicate_merge_key_in_cluster/script
similarity index 100%
rename from acceptance/bundle/validate/duplicate_yaml_merge_key/script
rename to acceptance/bundle/validate/yaml_anchors/duplicate_merge_key_in_cluster/script
diff --git a/acceptance/bundle/validate/yaml_anchors/duplicate_merge_keys/databricks.yml b/acceptance/bundle/validate/yaml_anchors/duplicate_merge_keys/databricks.yml
new file mode 100644
index 00000000000..638c26ee0ad
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_anchors/duplicate_merge_keys/databricks.yml
@@ -0,0 +1,18 @@
+bundle:
+  name: test-bundle
+
+variables:
+  x:
+    default: base
+
+definitions:
+  a: &a
+    x: first
+  b: &b
+    x: second
+
+targets:
+  dev:
+    variables:
+      <<: *a
+      <<: *b
diff --git a/acceptance/bundle/validate/yaml_anchors/duplicate_merge_keys/out.test.toml b/acceptance/bundle/validate/yaml_anchors/duplicate_merge_keys/out.test.toml
new file mode 100644
index 00000000000..a927a5fbc06
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_anchors/duplicate_merge_keys/out.test.toml
@@ -0,0 +1,2 @@
+Cloud = false
+EnvMatrix.DMS = ["", "true"]
diff --git a/acceptance/bundle/validate/yaml_anchors/duplicate_merge_keys/output.txt b/acceptance/bundle/validate/yaml_anchors/duplicate_merge_keys/output.txt
new file mode 100644
index 00000000000..2efbf8faf73
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_anchors/duplicate_merge_keys/output.txt
@@ -0,0 +1,9 @@
+
+>>> [CLI] bundle validate -t dev
+Error: duplicate YAML merge key ('<<') is not allowed; to merge multiple maps, use a sequence: '<<: [*anchor1, *anchor2]'
+  in databricks.yml:18:7
+
+
+Found 1 error
+
+Exit code: 1
diff --git a/acceptance/bundle/validate/yaml_anchors/duplicate_merge_keys/script b/acceptance/bundle/validate/yaml_anchors/duplicate_merge_keys/script
new file mode 100644
index 00000000000..e316f5883d8
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_anchors/duplicate_merge_keys/script
@@ -0,0 +1,2 @@
+# Two '<<' keys in target variables are an error.
+errcode trace $CLI bundle validate -t dev
diff --git a/acceptance/bundle/validate/yaml_anchors/inline_merge_mapping/databricks.yml b/acceptance/bundle/validate/yaml_anchors/inline_merge_mapping/databricks.yml
new file mode 100644
index 00000000000..c79cadfe0a8
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_anchors/inline_merge_mapping/databricks.yml
@@ -0,0 +1,11 @@
+bundle:
+  name: test-bundle
+
+variables:
+  x:
+    default: base
+
+targets:
+  dev:
+    variables:
+      <<: {x: overridden}
diff --git a/acceptance/bundle/validate/yaml_anchors/inline_merge_mapping/out.test.toml b/acceptance/bundle/validate/yaml_anchors/inline_merge_mapping/out.test.toml
new file mode 100644
index 00000000000..a927a5fbc06
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_anchors/inline_merge_mapping/out.test.toml
@@ -0,0 +1,2 @@
+Cloud = false
+EnvMatrix.DMS = ["", "true"]
diff --git a/acceptance/bundle/validate/yaml_anchors/inline_merge_mapping/output.txt b/acceptance/bundle/validate/yaml_anchors/inline_merge_mapping/output.txt
new file mode 100644
index 00000000000..85dc1ee379b
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_anchors/inline_merge_mapping/output.txt
@@ -0,0 +1,8 @@
+
+>>> [CLI] bundle validate
+Error: failed to load [TEST_TMP_DIR]/databricks.yml: yaml ([TEST_TMP_DIR]/databricks.yml:11:11): map merge requires map or sequence of maps as the value
+
+
+Found 1 error
+
+Exit code: 1
diff --git a/acceptance/bundle/validate/yaml_anchors/inline_merge_mapping/script b/acceptance/bundle/validate/yaml_anchors/inline_merge_mapping/script
new file mode 100644
index 00000000000..1724b135e5e
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_anchors/inline_merge_mapping/script
@@ -0,0 +1,2 @@
+# An inline mapping as the value of '<<' in target variables.
+errcode trace $CLI bundle validate
diff --git a/acceptance/bundle/validate/yaml_anchors/inline_merge_mapping/test.toml b/acceptance/bundle/validate/yaml_anchors/inline_merge_mapping/test.toml
new file mode 100644
index 00000000000..84101454028
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_anchors/inline_merge_mapping/test.toml
@@ -0,0 +1 @@
+Badness = "The YAML merge key spec allows a single mapping as the value of the merge key, but it is rejected."
diff --git a/acceptance/bundle/validate/yaml_anchors/invalid_merge_sequence_member/databricks.yml b/acceptance/bundle/validate/yaml_anchors/invalid_merge_sequence_member/databricks.yml
new file mode 100644
index 00000000000..2c0bf7fe5b8
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_anchors/invalid_merge_sequence_member/databricks.yml
@@ -0,0 +1,15 @@
+bundle:
+  name: test-bundle
+
+variables:
+  x:
+    default: base
+
+definitions:
+  overrides: &overrides
+    x: overridden
+
+targets:
+  dev:
+    variables:
+      <<: [*overrides, 17]
diff --git a/acceptance/bundle/validate/yaml_anchors/invalid_merge_sequence_member/out.test.toml b/acceptance/bundle/validate/yaml_anchors/invalid_merge_sequence_member/out.test.toml
new file mode 100644
index 00000000000..a927a5fbc06
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_anchors/invalid_merge_sequence_member/out.test.toml
@@ -0,0 +1,2 @@
+Cloud = false
+EnvMatrix.DMS = ["", "true"]
diff --git a/acceptance/bundle/validate/yaml_anchors/invalid_merge_sequence_member/output.txt b/acceptance/bundle/validate/yaml_anchors/invalid_merge_sequence_member/output.txt
new file mode 100644
index 00000000000..770f0193a58
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_anchors/invalid_merge_sequence_member/output.txt
@@ -0,0 +1,8 @@
+
+>>> [CLI] bundle validate -t dev
+Error: failed to load [TEST_TMP_DIR]/databricks.yml: yaml ([TEST_TMP_DIR]/databricks.yml:15:11): map merge requires map or sequence of maps as the value
+
+
+Found 1 error
+
+Exit code: 1
diff --git a/acceptance/bundle/validate/yaml_anchors/invalid_merge_sequence_member/script b/acceptance/bundle/validate/yaml_anchors/invalid_merge_sequence_member/script
new file mode 100644
index 00000000000..497e2fefa39
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_anchors/invalid_merge_sequence_member/script
@@ -0,0 +1,2 @@
+# A scalar among the maps merged with '<<: [...]' is an error.
+errcode trace $CLI bundle validate -t dev
diff --git a/acceptance/bundle/validate/target_variable_full_def_merge_key/databricks.yml b/acceptance/bundle/validate/yaml_anchors/target_variable_full_def/databricks.yml
similarity index 100%
rename from acceptance/bundle/validate/target_variable_full_def_merge_key/databricks.yml
rename to acceptance/bundle/validate/yaml_anchors/target_variable_full_def/databricks.yml
diff --git a/acceptance/bundle/validate/yaml_anchors/target_variable_full_def/out.test.toml b/acceptance/bundle/validate/yaml_anchors/target_variable_full_def/out.test.toml
new file mode 100644
index 00000000000..a927a5fbc06
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_anchors/target_variable_full_def/out.test.toml
@@ -0,0 +1,2 @@
+Cloud = false
+EnvMatrix.DMS = ["", "true"]
diff --git a/acceptance/bundle/validate/target_variable_full_def_merge_key/output.txt b/acceptance/bundle/validate/yaml_anchors/target_variable_full_def/output.txt
similarity index 100%
rename from acceptance/bundle/validate/target_variable_full_def_merge_key/output.txt
rename to acceptance/bundle/validate/yaml_anchors/target_variable_full_def/output.txt
diff --git a/acceptance/bundle/validate/target_variable_full_def_merge_key/script b/acceptance/bundle/validate/yaml_anchors/target_variable_full_def/script
similarity index 100%
rename from acceptance/bundle/validate/target_variable_full_def_merge_key/script
rename to acceptance/bundle/validate/yaml_anchors/target_variable_full_def/script
diff --git a/acceptance/bundle/validate/target_variable_merge_key_precedence/databricks.yml b/acceptance/bundle/validate/yaml_anchors/target_variable_precedence/databricks.yml
similarity index 100%
rename from acceptance/bundle/validate/target_variable_merge_key_precedence/databricks.yml
rename to acceptance/bundle/validate/yaml_anchors/target_variable_precedence/databricks.yml
diff --git a/acceptance/bundle/validate/yaml_anchors/target_variable_precedence/out.test.toml b/acceptance/bundle/validate/yaml_anchors/target_variable_precedence/out.test.toml
new file mode 100644
index 00000000000..a927a5fbc06
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_anchors/target_variable_precedence/out.test.toml
@@ -0,0 +1,2 @@
+Cloud = false
+EnvMatrix.DMS = ["", "true"]
diff --git a/acceptance/bundle/validate/target_variable_merge_key_precedence/output.txt b/acceptance/bundle/validate/yaml_anchors/target_variable_precedence/output.txt
similarity index 100%
rename from acceptance/bundle/validate/target_variable_merge_key_precedence/output.txt
rename to acceptance/bundle/validate/yaml_anchors/target_variable_precedence/output.txt
diff --git a/acceptance/bundle/validate/target_variable_merge_key_precedence/script b/acceptance/bundle/validate/yaml_anchors/target_variable_precedence/script
similarity index 100%
rename from acceptance/bundle/validate/target_variable_merge_key_precedence/script
rename to acceptance/bundle/validate/yaml_anchors/target_variable_precedence/script
diff --git a/acceptance/bundle/validate/target_variable_merge_key_precedence/test.toml b/acceptance/bundle/validate/yaml_anchors/target_variable_precedence/test.toml
similarity index 100%
rename from acceptance/bundle/validate/target_variable_merge_key_precedence/test.toml
rename to acceptance/bundle/validate/yaml_anchors/target_variable_precedence/test.toml
diff --git a/acceptance/bundle/validate/target_variable_shorthand_alias/databricks.yml b/acceptance/bundle/validate/yaml_anchors/target_variable_shorthand_alias/databricks.yml
similarity index 100%
rename from acceptance/bundle/validate/target_variable_shorthand_alias/databricks.yml
rename to acceptance/bundle/validate/yaml_anchors/target_variable_shorthand_alias/databricks.yml
diff --git a/acceptance/bundle/validate/yaml_anchors/target_variable_shorthand_alias/out.test.toml b/acceptance/bundle/validate/yaml_anchors/target_variable_shorthand_alias/out.test.toml
new file mode 100644
index 00000000000..a927a5fbc06
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_anchors/target_variable_shorthand_alias/out.test.toml
@@ -0,0 +1,2 @@
+Cloud = false
+EnvMatrix.DMS = ["", "true"]
diff --git a/acceptance/bundle/validate/target_variable_shorthand_alias/output.txt b/acceptance/bundle/validate/yaml_anchors/target_variable_shorthand_alias/output.txt
similarity index 100%
rename from acceptance/bundle/validate/target_variable_shorthand_alias/output.txt
rename to acceptance/bundle/validate/yaml_anchors/target_variable_shorthand_alias/output.txt
diff --git a/acceptance/bundle/validate/target_variable_shorthand_alias/script b/acceptance/bundle/validate/yaml_anchors/target_variable_shorthand_alias/script
similarity index 100%
rename from acceptance/bundle/validate/target_variable_shorthand_alias/script
rename to acceptance/bundle/validate/yaml_anchors/target_variable_shorthand_alias/script
diff --git a/acceptance/bundle/validate/yaml_anchors/test.toml b/acceptance/bundle/validate/yaml_anchors/test.toml
new file mode 100644
index 00000000000..e9cede5e28a
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_anchors/test.toml
@@ -0,0 +1,4 @@
+# Errors for invalid YAML print the full path of the file; normalize Windows separators.
+[[Repls]]
+Old = '\\'
+New = '/'
diff --git a/acceptance/bundle/validate/yaml_duplicate_keys/resource_fields/databricks.yml b/acceptance/bundle/validate/yaml_duplicate_keys/resource_fields/databricks.yml
new file mode 100644
index 00000000000..d29746866db
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_duplicate_keys/resource_fields/databricks.yml
@@ -0,0 +1,16 @@
+bundle:
+  name: test-bundle
+
+resources:
+  jobs:
+    j:
+      name: first
+      max_concurrent_runs: 1
+      tags:
+        a: one
+        shared: first
+      name: second
+      max_concurrent_runs: 5
+      tags:
+        b: two
+        shared: second
diff --git a/acceptance/bundle/validate/yaml_duplicate_keys/resource_fields/out.test.toml b/acceptance/bundle/validate/yaml_duplicate_keys/resource_fields/out.test.toml
new file mode 100644
index 00000000000..a927a5fbc06
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_duplicate_keys/resource_fields/out.test.toml
@@ -0,0 +1,2 @@
+Cloud = false
+EnvMatrix.DMS = ["", "true"]
diff --git a/acceptance/bundle/validate/yaml_duplicate_keys/resource_fields/output.txt b/acceptance/bundle/validate/yaml_duplicate_keys/resource_fields/output.txt
new file mode 100644
index 00000000000..c395fba7081
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_duplicate_keys/resource_fields/output.txt
@@ -0,0 +1,19 @@
+
+>>> [CLI] bundle validate
+Name: test-bundle
+Target: default
+Workspace:
+  User: [USERNAME]
+  Path: /Workspace/Users/[USERNAME]/.bundle/test-bundle/default
+
+Validation OK!
+
+>>> [CLI] bundle validate -o json
+{
+  "name": "second",
+  "max_concurrent_runs": 5,
+  "tags": {
+    "b": "two",
+    "shared": "second"
+  }
+}
diff --git a/acceptance/bundle/validate/yaml_duplicate_keys/resource_fields/script b/acceptance/bundle/validate/yaml_duplicate_keys/resource_fields/script
new file mode 100644
index 00000000000..7b6d7caa93b
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_duplicate_keys/resource_fields/script
@@ -0,0 +1,5 @@
+# Duplicate keys in a mapping are accepted without a warning, although YAML requires keys to be unique.
+trace $CLI bundle validate
+
+# The later value replaces the earlier one as a whole: maps are not merged ("a" is gone).
+trace $CLI bundle validate -o json | jq '.resources.jobs.j | {name, max_concurrent_runs, tags}'
diff --git a/acceptance/bundle/validate/yaml_duplicate_keys/resource_fields/test.toml b/acceptance/bundle/validate/yaml_duplicate_keys/resource_fields/test.toml
new file mode 100644
index 00000000000..af65b8438c4
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_duplicate_keys/resource_fields/test.toml
@@ -0,0 +1 @@
+Badness = "Duplicate keys are accepted silently (the later one wins); YAML requires keys to be unique."
diff --git a/acceptance/bundle/validate/yaml_duplicate_keys/shadowed_invalid_subtree/databricks.yml b/acceptance/bundle/validate/yaml_duplicate_keys/shadowed_invalid_subtree/databricks.yml
new file mode 100644
index 00000000000..03d9373eed1
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_duplicate_keys/shadowed_invalid_subtree/databricks.yml
@@ -0,0 +1,11 @@
+bundle:
+  name: test-bundle
+
+resources:
+  jobs:
+    j:
+      name: test
+      tags:
+        7: invalid-key
+      tags:
+        good: ok
diff --git a/acceptance/bundle/validate/yaml_duplicate_keys/shadowed_invalid_subtree/out.test.toml b/acceptance/bundle/validate/yaml_duplicate_keys/shadowed_invalid_subtree/out.test.toml
new file mode 100644
index 00000000000..a927a5fbc06
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_duplicate_keys/shadowed_invalid_subtree/out.test.toml
@@ -0,0 +1,2 @@
+Cloud = false
+EnvMatrix.DMS = ["", "true"]
diff --git a/acceptance/bundle/validate/yaml_duplicate_keys/shadowed_invalid_subtree/output.txt b/acceptance/bundle/validate/yaml_duplicate_keys/shadowed_invalid_subtree/output.txt
new file mode 100644
index 00000000000..8c0f7149fad
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_duplicate_keys/shadowed_invalid_subtree/output.txt
@@ -0,0 +1,8 @@
+
+>>> [CLI] bundle validate
+Error: failed to load [TEST_TMP_DIR]/databricks.yml: yaml ([TEST_TMP_DIR]/databricks.yml:9:9): invalid key tag: !!int
+
+
+Found 1 error
+
+Exit code: 1
diff --git a/acceptance/bundle/validate/yaml_duplicate_keys/shadowed_invalid_subtree/script b/acceptance/bundle/validate/yaml_duplicate_keys/shadowed_invalid_subtree/script
new file mode 100644
index 00000000000..58b74e2f574
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_duplicate_keys/shadowed_invalid_subtree/script
@@ -0,0 +1,2 @@
+# A value replaced by a later duplicate key is still loaded, so its invalid (integer) key is rejected.
+errcode trace $CLI bundle validate
diff --git a/acceptance/bundle/validate/yaml_duplicate_keys/shadowed_invalid_subtree/test.toml b/acceptance/bundle/validate/yaml_duplicate_keys/shadowed_invalid_subtree/test.toml
new file mode 100644
index 00000000000..bad67f27bd1
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_duplicate_keys/shadowed_invalid_subtree/test.toml
@@ -0,0 +1 @@
+Badness = 'The duplicate tags key is accepted silently (the later one wins); YAML requires keys to be unique.'
diff --git a/acceptance/bundle/validate/yaml_duplicate_keys/target_variable_default/databricks.yml b/acceptance/bundle/validate/yaml_duplicate_keys/target_variable_default/databricks.yml
new file mode 100644
index 00000000000..38c97681a98
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_duplicate_keys/target_variable_default/databricks.yml
@@ -0,0 +1,13 @@
+bundle:
+  name: test-bundle
+
+variables:
+  x:
+    default: base
+
+targets:
+  dev:
+    variables:
+      x:
+        default: first
+        default: second
diff --git a/acceptance/bundle/validate/yaml_duplicate_keys/target_variable_default/out.test.toml b/acceptance/bundle/validate/yaml_duplicate_keys/target_variable_default/out.test.toml
new file mode 100644
index 00000000000..a927a5fbc06
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_duplicate_keys/target_variable_default/out.test.toml
@@ -0,0 +1,2 @@
+Cloud = false
+EnvMatrix.DMS = ["", "true"]
diff --git a/acceptance/bundle/validate/yaml_duplicate_keys/target_variable_default/output.txt b/acceptance/bundle/validate/yaml_duplicate_keys/target_variable_default/output.txt
new file mode 100644
index 00000000000..5c429a0449c
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_duplicate_keys/target_variable_default/output.txt
@@ -0,0 +1,6 @@
+
+>>> [CLI] bundle validate -t dev -o json
+{
+  "default": "second",
+  "value": "second"
+}
diff --git a/acceptance/bundle/validate/yaml_duplicate_keys/target_variable_default/script b/acceptance/bundle/validate/yaml_duplicate_keys/target_variable_default/script
new file mode 100644
index 00000000000..771eda950ef
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_duplicate_keys/target_variable_default/script
@@ -0,0 +1,2 @@
+# With a duplicate default key in a target variable override, the last one wins and it is a full definition.
+trace $CLI bundle validate -t dev -o json | jq .variables.x
diff --git a/acceptance/bundle/validate/yaml_duplicate_keys/target_variable_default/test.toml b/acceptance/bundle/validate/yaml_duplicate_keys/target_variable_default/test.toml
new file mode 100644
index 00000000000..42d04e8a1ef
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_duplicate_keys/target_variable_default/test.toml
@@ -0,0 +1 @@
+Badness = 'The duplicate default key is accepted silently (the later one wins); YAML requires keys to be unique.'
diff --git a/acceptance/bundle/validate/yaml_duplicate_keys/test.toml b/acceptance/bundle/validate/yaml_duplicate_keys/test.toml
new file mode 100644
index 00000000000..e9cede5e28a
--- /dev/null
+++ b/acceptance/bundle/validate/yaml_duplicate_keys/test.toml
@@ -0,0 +1,4 @@
+# Errors for invalid YAML print the full path of the file; normalize Windows separators.
+[[Repls]]
+Old = '\\'
+New = '/'