v3: verify shared vlib fallback inputs

Author: medvednikov

vlib/v/builder/c_error_report.v

@@ -576,16 +576,16 @@ fn (b &Builder) matches_v3_fallback_inputs(report ExternalCErrorBugReport) bool
 		return false
 	}
 	mut stable_digests := map[string]string{}
-	vlib_root := os.real_path(os.join_path(b.pref.vroot, 'vlib')).trim_right(os.path_separator)
+	builtin_root :=
+		os.real_path(os.join_path(b.pref.vroot, 'vlib', 'builtin')).trim_right(os.path_separator)
 	for file in b.parsed_files {
 		if file.path == '' || file.source_digest == '' {
 			continue
 		}
 		path := os.real_path(file.path)
-		// Mirror macos_v3_fallback_report_sources: V1 and V3 intentionally parse
-		// different bundled compiler-support files, so compare only caller/project and
-		// installed-module inputs.
-		if path == vlib_root || path.starts_with(vlib_root + os.path_separator) {
+		// Mirror macos_v3_fallback_report_sources: only the opposite v3_backend
+		// ownership-interface variants intentionally differ between the compilers.
+		if v3_fallback_backend_specific_builtin_source(path, builtin_root) {
 			continue
 		}
 		if previous := stable_digests[path] {
@@ -606,6 +606,11 @@ fn (b &Builder) matches_v3_fallback_inputs(report ExternalCErrorBugReport) bool
 	return true
 }
 
+fn v3_fallback_backend_specific_builtin_source(path string, builtin_root string) bool {
+	return (path == builtin_root || path.starts_with(builtin_root + os.path_separator))
+		&& os.file_name(path) in ['ownership_interface_d_v3_backend.v', 'ownership_interface_notd_v3_backend.v']
+}
+
 fn discard_unverified_v3_fallback_report() {
 	eprintln('note: source inputs changed before the stable compiler retry completed; the V3 fallback report was not submitted.')
 }

vlib/v/builder/c_error_report_test.v

@@ -378,6 +378,10 @@ fn test_v3_fallback_input_verification_uses_stable_parser_digests() {
 	vroot := os.real_path(@VEXEROOT)
 	path := os.real_path(os.join_path(os.temp_dir(), 'v3_retry_input_main.v'))
 	parsed_digest := sha256.hexhash('the exact stable parser bytes')
+	shared_builtin_path := os.real_path(os.join_path(vroot, 'vlib', 'builtin', 'builtin.v'))
+	shared_builtin_digest := sha256.hexhash('shared builtin parser bytes')
+	shared_vlib_path := os.real_path(os.join_path(vroot, 'vlib', 'os', 'os.v'))
+	shared_vlib_digest := sha256.hexhash('shared vlib parser bytes')
 	b := &Builder{
 		pref:         &pref.Preferences{
 			vroot: vroot
@@ -387,25 +391,53 @@ fn test_v3_fallback_input_verification_uses_stable_parser_digests() {
 				path:          path
 				source_digest: parsed_digest
 			},
-			// Bundled vlib support files intentionally differ between V1 and V3 and are
-			// excluded from both input sets.
 			&ast.File{
-				path:          os.join_path(vroot, 'vlib', 'builtin', 'builtin.v')
-				source_digest: sha256.hexhash('stable compiler builtin')
+				path:          shared_builtin_path
+				source_digest: shared_builtin_digest
+			},
+			// V1 and V3 select opposite versions of this internal interface.
+			&ast.File{
+				path:          os.join_path(vroot, 'vlib', 'builtin',
+					'ownership_interface_notd_v3_backend.v')
+				source_digest: sha256.hexhash('stable compiler interface')
+			},
+			&ast.File{
+				path:          shared_vlib_path
+				source_digest: shared_vlib_digest
 			},
 		]
 	}
 	matching := ExternalCErrorBugReport{
 		input_digests:          {
-			path: parsed_digest
+			path:                parsed_digest
+			shared_builtin_path: shared_builtin_digest
+			shared_vlib_path:    shared_vlib_digest
 		}
 		input_digests_complete: true
 	}
 	assert b.matches_v3_fallback_inputs(matching)
 	assert !b.matches_v3_fallback_inputs(ExternalCErrorBugReport{
 		...matching
 		input_digests: {
-			path: sha256.hexhash('rewritten after V3')
+			path:                sha256.hexhash('rewritten after V3')
+			shared_builtin_path: shared_builtin_digest
+			shared_vlib_path:    shared_vlib_digest
+		}
+	})
+	assert !b.matches_v3_fallback_inputs(ExternalCErrorBugReport{
+		...matching
+		input_digests: {
+			path:                parsed_digest
+			shared_builtin_path: sha256.hexhash('rewritten shared builtin')
+			shared_vlib_path:    shared_vlib_digest
+		}
+	})
+	assert !b.matches_v3_fallback_inputs(ExternalCErrorBugReport{
+		...matching
+		input_digests: {
+			path:                parsed_digest
+			shared_builtin_path: shared_builtin_digest
+			shared_vlib_path:    sha256.hexhash('rewritten shared vlib')
 		}
 	})
 	assert !b.matches_v3_fallback_inputs(ExternalCErrorBugReport{

vlib/v3/driver/driver.v

@@ -6395,16 +6395,15 @@ fn request_macos_v3_c_error_fallback_from_message(fallback_file string, report_d
 fn macos_v3_fallback_report_sources(a &flat.FlatAst, vroot string) map[string]string {
 	mut sources := map[string]string{}
 	mut ambiguous := map[string]bool{}
-	vlib_root := os.real_path(os.join_path(vroot, 'vlib')).trim_right(os.path_separator)
+	builtin_root :=
+		os.real_path(os.join_path(vroot, 'vlib', 'builtin')).trim_right(os.path_separator)
 	for _, file in a.source_files {
 		if (file.name.ends_with('.v') || file.name.ends_with('.vv')
 			|| file.name.ends_with('.vsh')) && file.has_source_sha256() {
 			path := os.real_path(file.name)
-			// V1 and V3 deliberately select different compiler-support implementations
-			// below the bundled vlib (for example V3's preallocated builtin). They are not
-			// caller inputs and cannot be required to appear in both ASTs. Project and
-			// installed-module sources remain covered, including directory builds.
-			if path == vlib_root || path.starts_with(vlib_root + os.path_separator) {
+			// V1 and V3 select opposite v3_backend ownership-interface files. All other
+			// bundled vlib sources are shared inputs and remain covered by verification.
+			if v3_fallback_backend_specific_builtin_source(path, builtin_root) {
 				continue
 			}
 			source_digest := file.source_sha256()
@@ -6424,6 +6423,11 @@ fn macos_v3_fallback_report_sources(a &flat.FlatAst, vroot string) map[string]st
 	return sources
 }
 
+fn v3_fallback_backend_specific_builtin_source(path string, builtin_root string) bool {
+	return (path == builtin_root || path.starts_with(builtin_root + os.path_separator))
+		&& os.file_name(path) in ['ownership_interface_d_v3_backend.v', 'ownership_interface_notd_v3_backend.v']
+}
+
 fn input_uses_minimal_literal_output_builtin(input_file string, prefs &pref.Preferences, is_test_command bool, is_checker_fixture bool) bool {
 	if prefs.backend != 'c' || prefs.target.os != 'macos' || is_test_command || is_checker_fixture
 		|| !(input_file.ends_with('.v') || input_file.ends_with('.vv')) || !os.is_file(input_file)

vlib/v3/driver/environment_test.v

@@ -99,29 +99,46 @@ fn test_macos_v3_fallback_report_sources_keep_parser_digests() {
 		os.rmdir_all(root) or {}
 	}
 	path := os.join_path(root, 'main.v')
-	vlib_path := os.join_path(root, 'vlib', 'builtin', 'internal.v')
-	os.mkdir_all(os.dir(vlib_path))!
+	backend_builtin_path := os.join_path(root, 'vlib', 'builtin',
+		'ownership_interface_d_v3_backend.v')
+	shared_builtin_path := os.join_path(root, 'vlib', 'builtin', 'internal.v')
+	shared_vlib_path := os.join_path(root, 'vlib', 'os', 'shared.v')
+	os.mkdir_all(os.dir(backend_builtin_path))!
+	os.mkdir_all(os.dir(shared_vlib_path))!
 	parsed_source := 'module main\nfn main() { println(42) }\n'
+	shared_builtin_source := 'module builtin\nfn shared_builtin_input() {}\n'
+	shared_vlib_source := 'module os\nfn shared_input() {}\n'
 	os.write_file(path, parsed_source)!
-	os.write_file(vlib_path, 'module builtin\nfn internal_only() {}\n')!
+	os.write_file(backend_builtin_path, 'module builtin\nfn v3_backend_only() {}\n')!
+	os.write_file(shared_builtin_path, shared_builtin_source)!
+	os.write_file(shared_vlib_path, shared_vlib_source)!
 	prefs := pref.new_preferences()
 	mut p := parser.Parser.new(prefs)
 	p.parse_into(path)
-	p.parse_into(vlib_path)
+	p.parse_into(backend_builtin_path)
+	p.parse_into(shared_builtin_path)
+	p.parse_into(shared_vlib_path)
 	assert p.diagnostics.len == 0, p.diagnostics.str()
 	// Replacing the file after parsing must not change the staged digest.
 	os.write_file(path, parsed_source.replace('42', 'private_value'))!
 	sources := macos_v3_fallback_report_sources(p.a, root)
 	real_path := os.real_path(path)
 	assert sources[real_path] == sha256.hexhash(parsed_source)
 	assert sources[real_path] != sha256.hexhash(os.read_file(path)!)
-	// Bundled compiler-support sources deliberately differ between V1 and V3 and are
-	// not caller inputs, so they do not make every exact-source verification fail.
-	assert os.real_path(vlib_path) !in sources
+	// Only the opposite v3_backend compiler-support variants are excluded. Shared
+	// builtin and other bundled vlib inputs remain protected by their parser digests.
+	assert os.real_path(backend_builtin_path) !in sources
+	assert sources[os.real_path(shared_builtin_path)] == sha256.hexhash(shared_builtin_source)
+	assert sources[os.real_path(shared_vlib_path)] == sha256.hexhash(shared_vlib_source)
 	report_dir := os.join_path(root, 'report')
 	assert stage_macos_v3_fallback_source_digests(report_dir, sources)
-	assert os.read_file(os.join_path(report_dir, macos_v3_c_error_v_sources_file))! == real_path
-	assert os.read_file(os.join_path(report_dir, macos_v3_c_error_v_source_digests_file))! == sha256.hexhash(parsed_source)
+	staged_paths := os.read_file(os.join_path(report_dir, macos_v3_c_error_v_sources_file))!
+	staged_digests :=
+		os.read_file(os.join_path(report_dir, macos_v3_c_error_v_source_digests_file))!
+	assert staged_paths == [real_path, os.real_path(shared_builtin_path),
+		os.real_path(shared_vlib_path)].join('\x00')
+	assert staged_digests == [sha256.hexhash(parsed_source), sha256.hexhash(shared_builtin_source),
+		sha256.hexhash(shared_vlib_source)].join('\x00')
 }
 
 fn test_parallel_cc_external_definition_precheck_uses_active_ast_directives() {