[HaoZeke]

stack arch --probe-sources and two --arch values

What and why

stack arch --probe-sources resolves each planned easyconfig's source_urls and sources on the families --arch names, then probes those URLs.
The suite locked one --arch, and the default of x86_64, aarch64, and riscv64 when --arch is absent.
It did not lock two families.
That pair is the comparison that decides the class: a miss is arch-missing when the other named family fetched the same source slot, and unreachable when neither did.
A family that was not named must not enter that comparison.

The probe already used the families parsed from --arch.
What was open was a regression that passes two of them, plus the how-to, which showed one family and all three and did not quote a pair.

Before and after

On the Kaleido fixture, a local server has only kaleido-0.2.1-manylinux1-x86_64.whl.
tests/source_probe.rs and tests/doc_walkthrough.rs copy the tree, substitute that server for __BASE_URL__, and run eb-stack.

--arch x86_64 --arch aarch64 --probe-sources exits 1 and prints:

Kaleido-0.2.1-GCCcore-15.2.0.eb source kaleido-0.2.1-manylinux2014-aarch64.whl is arch-missing on aarch64: <base>/kaleido-0.2.1-manylinux2014-aarch64.whl (attempt 1/3 HEAD=status:404 RANGE=status:404)
parse_failed=0 unsupported=0 flagged=0 source_unreachable=0 source_arch_missing=1

The text does not contain riscv64.
--arch aarch64 --arch x86_64 prints the same text.
--arch x86_64/amd/zen4 --arch aarch64/neoverse_v1 prints the same text.
eb_stack_arch with "arch": ["x86_64", "aarch64"] returns that finding line and isError: true.

--arch aarch64 --arch riscv64 --probe-sources exits 1.
Both wheels are unreachable, the count line is source_unreachable=2 source_arch_missing=0, and the text does not contain x86_64.
eb_stack_arch returns those two lines.

--arch aarch64 --arch aarch64/neoverse_v1 matches --arch aarch64 alone: one unreachable line and source_unreachable=1.

docs/orgmode/howto/arch-unsupported.org now quotes the x86_64 plus aarch64 run.
The command reference, the --probe-sources help, and the eb_stack_arch description say two names are compared only with each other.
llms-full.txt matches that manual.

Tests

• Formatting: cargo +stable fmt --all --check exited 0.
• Lints: cargo +stable clippy --locked --all-targets -- -D warnings exited 0 (Finished dev profile).
• Full suite: cargo +stable test --locked --all-targets -- --test-threads=8 exited 0, with 93 suites, 1504 passed, 0 failed, 10 ignored.
• Packaging: cargo +stable package --locked exited 0, packaged 1532 files, 12.6MiB (5.6MiB compressed), and finished the verify compile.
• Hooks: uvx prek run -a exited 0.
  Trailing whitespace, end of file, YAML, Tom's Obvious Minimal Language (TOML), merge conflicts, large files, private keys, and codespell passed.
• New and touched tests: stack_arch_probe_with_two_arches_compares_only_that_pair, the_source_probe_howto_quotes_the_output_it_prints, and llms_txt_matches_the_org_manual passed.

Toolchain: cargo +stable, rustc 1.99.1.

Repro

cargo test --locked --test source_probe -- stack_arch_probe_with_two_arches_compares_only_that_pair
cargo test --locked --test doc_walkthrough -- the_source_probe_howto_quotes_the_output_it_prints

The how-to command, on a copy of the fixture whose __BASE_URL__ is that server:

eb-stack stack arch \
  --arch x86_64 \
  --arch aarch64 \
  --easystack tests/source_probe_fixtures/easystacks/kaleido.yml \
  --easyconfigs tests/source_probe_fixtures/easyconfigs \
  --probe-sources

---

Note

Medium Risk
Changes core dependency-order graph construction for a new CLI/MCP path; incorrect installed matching could omit required builds, while probe changes are mostly documented regression tests.

Overview
Adds stack order --installed so build orders skip modules already on the site (module list or Lmod tree, same inventory as stack gap --installed) and do not walk their dependencies. --filter-deps still runs first; stdout prints installed=N; eb_stack_order exposes the same installed input and count.

The build-order graph walk is refactored through build_order_against_installed / graph_from_keys_against_installed, with unit tests for installed leaves and GCC-family resolution.

Separately, docs, CHANGELOG, and tests lock stack arch --probe-sources when two --arch families are named: misses are arch-missing only if the other probed family fetched that source slot, otherwise unreachable, without consulting families left off the command.

^{Reviewed by Cursor Bugbot for commit 7e8f8d3. Bugbot is set up for automated code reviews on this repo. Configure here.}