Fix apps run-local --entry-point with absolute paths

.nextchanges/cli/apps-run-local-absolute-entry-point.md

@@ -0,0 +1 @@
+* Fix `apps run-local --entry-point` failing with absolute paths to the app spec file. ([#6918](https://github.com/databricks/cli/pull/6918))

libs/apps/runlocal/spec.go

@@ -36,8 +36,12 @@ func (a *AppSpec) GetFileName() string {
 func ReadAppSpecFile(config *Config) (*AppSpec, error) {
 	spec := &AppSpec{config: config}
 	for _, file := range config.AppSpecFiles {
+		// An absolute entry point is used verbatim; relative names resolve under AppPath.
+		if !filepath.IsAbs(file) {
+			file = filepath.Join(config.AppPath, file)
+		}
 		// Read the yaml file
-		yamlFile, err := os.ReadFile(filepath.Join(config.AppPath, file))
+		yamlFile, err := os.ReadFile(file)
 		if errors.Is(err, fs.ErrNotExist) {
 			continue
 		}

libs/apps/runlocal/spec_test.go

@@ -2,12 +2,44 @@ package runlocal
 
 import (
 	"context"
+	"os"
+	"path/filepath"
 	"testing"
 
 	"github.com/databricks/cli/libs/env"
 	"github.com/stretchr/testify/require"
 )
 
+func TestReadAppSpecFile(t *testing.T) {
+	appDir := t.TempDir()
+	specDir := t.TempDir()
+
+	specYAML := "command:\n  - python\n  - app.py\n"
+	require.NoError(t, os.WriteFile(filepath.Join(appDir, "app.yml"), []byte(specYAML), 0o644))
+	// Absolute spec lives outside the app dir so the test proves the
+	// path is used verbatim instead of joined with AppPath.
+	absSpec := filepath.Join(specDir, "custom.yml")
+	require.NoError(t, os.WriteFile(absSpec, []byte(specYAML), 0o644))
+
+	t.Run("relative path", func(t *testing.T) {
+		spec, err := ReadAppSpecFile(&Config{AppPath: appDir, AppSpecFiles: []string{"app.yml"}})
+		require.NoError(t, err)
+		require.Equal(t, []string{"python", "app.py"}, spec.Command)
+	})
+
+	t.Run("absolute path", func(t *testing.T) {
+		spec, err := ReadAppSpecFile(&Config{AppPath: appDir, AppSpecFiles: []string{absSpec}})
+		require.NoError(t, err)
+		require.Equal(t, []string{"python", "app.py"}, spec.Command)
+	})
+
+	t.Run("missing file returns empty spec", func(t *testing.T) {
+		spec, err := ReadAppSpecFile(&Config{AppPath: appDir, AppSpecFiles: []string{"does-not-exist.yml"}})
+		require.NoError(t, err)
+		require.Empty(t, spec.Command)
+	})
+}
+
 func TestAppSpecLoadEnvVars(t *testing.T) {
 	tempDir := t.TempDir()
 	config := &Config{