Add semantic configuration profile comparison

internal/config/pipeline_profiles_test.go

@@ -318,6 +318,43 @@ whisperx:
 	}
 }
 
+func TestEffectivePipelineValuesIgnoreEquivalentSourceLayout(t *testing.T) {
+	dir := t.TempDir()
+	monolithicPath := writePipelineSource(t, dir, "monolithic.yml", `workspace:
+  root: /srv/narratio
+whisperx:
+  transcribe_url: https://transcription.example.com/transcribe
+  language: en
+`)
+	composedPath := writePipelineSource(t, dir, "pipeline.yml", `composition:
+  imports: [workspace.yml]
+whisperx:
+  language: en
+  transcribe_url: https://transcription.example.com/transcribe
+`)
+	writePipelineSource(t, dir, "workspace.yml", "workspace:\n  root: /srv/narratio\n")
+
+	monolithic, err := LoadPipeline(monolithicPath)
+	if err != nil {
+		t.Fatal(err)
+	}
+	composed, err := LoadPipeline(composedPath)
+	if err != nil {
+		t.Fatal(err)
+	}
+	monolithicValues, err := EffectivePipelineValues(monolithic)
+	if err != nil {
+		t.Fatal(err)
+	}
+	composedValues, err := EffectivePipelineValues(composed)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !reflect.DeepEqual(monolithicValues, composedValues) {
+		t.Fatalf("equivalent effective values differ:\nmonolithic=%#v\ncomposed=%#v", monolithicValues, composedValues)
+	}
+}
+
 func TestPipelineEffectiveDigestExcludesProfileIdentity(t *testing.T) {
 	dir := t.TempDir()
 	rootPath := writeProfilePipeline(t, dir, profileComposition("production", "production", "testing"))
@@ -340,6 +377,53 @@ func TestPipelineEffectiveDigestExcludesProfileIdentity(t *testing.T) {
 	}
 }
 
+func TestLoadPipelineProfilePairResolvesIndependentEffectivePipelines(t *testing.T) {
+	dir := t.TempDir()
+	rootPath := writeProfilePipeline(t, dir, `composition:
+  imports: [base.yml]
+  default_profile: production
+  profiles:
+    production:
+      overlay: production.yml
+    testing:
+      overlay: testing.yml
+whisperx:
+  transcribe_url: https://transcription.example.com/transcribe
+`)
+	writePipelineSource(t, dir, "base.yml", "workspace:\n  root: /srv/base\n")
+	writePipelineSource(t, dir, "production.yml", "workspace:\n  root: /srv/production\nwhisperx:\n  language: en\n")
+	writePipelineSource(t, dir, "testing.yml", "workspace:\n  root: /srv/testing\nwhisperx:\n  language: fr\n")
+
+	production, testing, err := LoadPipelineProfilePair(rootPath, "production", "testing")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if production.Workspace.Root != "/srv/production" || production.WhisperX.Language != "en" {
+		t.Fatalf("production pair result = %#v", production)
+	}
+	if testing.Workspace.Root != "/srv/testing" || testing.WhisperX.Language != "fr" {
+		t.Fatalf("testing pair result = %#v", testing)
+	}
+	production.Workspace.Root = "/mutated-left"
+	if testing.Workspace.Root != "/srv/testing" {
+		t.Fatalf("right profile shared mutable state with left: %q", testing.Workspace.Root)
+	}
+	testingFirst, productionSecond, err := LoadPipelineProfilePair(rootPath, "testing", "production")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if testingFirst.Workspace.Root != "/srv/testing" || productionSecond.Workspace.Root != "/srv/production" {
+		t.Fatalf("reversed profile pair = testing=%q production=%q", testingFirst.Workspace.Root, productionSecond.Workspace.Root)
+	}
+
+	if _, _, err := LoadPipelineProfilePair(rootPath, "production", "production"); err == nil || !strings.Contains(err.Error(), "must differ") {
+		t.Fatalf("equal profile pair error = %v, want selection rejection", err)
+	}
+	if _, _, err := LoadPipelineProfilePair(rootPath, "unknown", "testing"); err == nil || !strings.Contains(err.Error(), "not declared") {
+		t.Fatalf("unknown profile pair error = %v, want selection rejection", err)
+	}
+}
+
 func TestLoadWithSessionOptionsCarriesExplicitProfilePresence(t *testing.T) {
 	dir := t.TempDir()
 	rootPath := writeProfilePipeline(t, dir, profileComposition("production", "production", "testing"))