acceptance: exit cleanly from -update when only regenerating outputs

Taskfile.yml

@@ -799,8 +799,7 @@ tasks:
     generates:
       - acceptance/bundle/refschema/out.fields.txt
     cmds:
-      - cmd: go test ./acceptance -run TestAccept/bundle/refschema -update &> /dev/null
-        ignore_error: true # -update returns non-zero exit code on changes
+      - go test ./acceptance -run TestAccept/bundle/refschema -update
 
   generate-schema:
     desc: Generate bundle JSON schema

acceptance/acceptance_test.go

@@ -899,35 +899,49 @@ func doComparison(t *testing.T, repls testdiff.ReplacementsContext, dirRef, dirN
 		valueNew = repls.Replace(valueNew)
 	}
 
+	// In update mode, regenerating the reference files is the goal: each branch below
+	// writes or removes the reference and returns without failing the test. Genuine
+	// problems still fail — read errors (via tryReading above), write errors (via
+	// require/testutil), and the both-missing case above.
+
 	// The test did not produce an expected output file.
 	if okRef && !okNew {
-		t.Errorf("Missing output file: %s", relPath)
 		if testdiff.OverwriteMode {
+			// The test no longer produces this output; drop the stale reference.
 			t.Logf("Removing output file: %s", relPath)
 			require.NoError(t, os.Remove(pathRef))
+			return
 		}
+		t.Errorf("Missing output file: %s", relPath)
 		return
 	}
 
 	// The test produced an unexpected output file.
 	if !okRef && okNew {
+		if testdiff.OverwriteMode {
+			t.Logf("Writing output file: %s", relPath)
+			testutil.WriteFile(t, pathRef, valueNew)
+			return
+		}
 		t.Errorf("Unexpected output file: %s\npathRef: %s\npathNew: %s", relPath, pathRef, pathNew)
 		if shouldShowDiff(pathNew, valueNew) {
 			testdiff.AssertEqualTexts(t, pathRef, pathNew, valueRef, valueNew)
 		}
-		if testdiff.OverwriteMode {
-			t.Logf("Writing output file: %s", relPath)
+		return
+	}
+
+	// In update mode, overwrite on any difference rather than calling
+	// AssertEqualTexts, which would mark the test failed.
+	if testdiff.OverwriteMode {
+		if valueRef != valueNew {
+			t.Logf("Overwriting existing output file: %s", relPath)
 			testutil.WriteFile(t, pathRef, valueNew)
 		}
 		return
 	}
 
 	// Compare the reference and new values.
 	equal := testdiff.AssertEqualTexts(t, pathRef, pathNew, valueRef, valueNew)
-	if !equal && testdiff.OverwriteMode {
-		t.Logf("Overwriting existing output file: %s", relPath)
-		testutil.WriteFile(t, pathRef, valueNew)
-	}
 
 	if VerboseTest && !equal && printedRepls != nil && !*printedRepls {
 		*printedRepls = true