Make it possible to test error messages produces by the clang tool

PiperOrigin-RevId: 809878622
Change-Id: Iecb0367bef06aee7525c8b8d6a2989fb1c3a6c22

Author: dvyukov

sandboxed_api/bazel/sapi.bzl

@@ -688,3 +688,26 @@ _sandboxed_library_gen = rule(
     },
     toolchains = use_cpp_toolchain(),
 )
+
+def _sandboxed_library_gen_errors_impl(ctx):
+    gen_action = [a for a in ctx.attr.target.actions if a.mnemonic == "SandboxedLibraryGen"][0]
+    ctx.actions.run_shell(
+        inputs = gen_action.inputs,
+        outputs = [ctx.outputs.errors],
+        arguments = gen_action.args,
+        # Replace bazel hashes with something stable.
+        command = "$@ 2>&1 | sed 's#[[:xdigit:]]\\{32,\\}#hexhexhexhexhexhexhexhexhexhexhex#g' > " + ctx.outputs.errors.path,
+        mnemonic = "SandboxedLibraryGenErrors",
+    )
+    return [DefaultInfo(files = depset([ctx.outputs.errors]))]
+
+# Helper target for tests that saves the errors generated by the clang generator
+# into the specified errors file. This allows to test errors messages produced
+# by the generator.
+sandboxed_library_gen_errors = rule(
+    implementation = _sandboxed_library_gen_errors_impl,
+    attrs = {
+        "target": attr.label(),
+        "errors": attr.output(),
+    },
+)

sandboxed_api/tools/clang_generator/diagnostics.cc

@@ -60,31 +60,14 @@ absl::optional<clang::SourceLocation> GetDiagnosticLocationFromStatus(
   return absl::nullopt;
 }
 
-namespace {
-
-clang::DiagnosticBuilder GetDiagnosticBuilder(
-    clang::DiagnosticsEngine& de, clang::SourceLocation loc,
-    clang::DiagnosticsEngine::Level level, absl::string_view message) {
+clang::DiagnosticBuilder Report(clang::DiagnosticsEngine& de,
+                                clang::SourceLocation loc,
+                                clang::DiagnosticsEngine::Level level,
+                                absl::string_view message) {
   clang::DiagnosticBuilder builder =
       de.Report(loc, de.getCustomDiagID(level, "header generation: %0"));
   builder.AddString(llvm::StringRef(message.data(), message.size()));
   return builder;
 }
 
-}  // namespace
-
-clang::DiagnosticBuilder ReportFatalError(clang::DiagnosticsEngine& de,
-                                          clang::SourceLocation loc,
-                                          absl::string_view message) {
-  return GetDiagnosticBuilder(de, loc, clang::DiagnosticsEngine::Fatal,
-                              message);
-}
-
-clang::DiagnosticBuilder ReportWarning(clang::DiagnosticsEngine& de,
-                                       clang::SourceLocation loc,
-                                       absl::string_view message) {
-  return GetDiagnosticBuilder(de, loc, clang::DiagnosticsEngine::Warning,
-                              message);
-}
-
 }  // namespace sapi

sandboxed_api/tools/clang_generator/diagnostics.h

@@ -38,13 +38,10 @@ absl::Status MakeStatusWithDiagnostic(clang::SourceLocation loc,
 absl::optional<clang::SourceLocation> GetDiagnosticLocationFromStatus(
     const absl::Status& status);
 
-clang::DiagnosticBuilder ReportWarning(clang::DiagnosticsEngine& de,
-                                       clang::SourceLocation loc,
-                                       absl::string_view message);
-
-clang::DiagnosticBuilder ReportFatalError(clang::DiagnosticsEngine& de,
-                                          clang::SourceLocation loc,
-                                          absl::string_view message);
+clang::DiagnosticBuilder Report(clang::DiagnosticsEngine& de,
+                                clang::SourceLocation loc,
+                                clang::DiagnosticsEngine::Level level,
+                                absl::string_view message);
 
 }  // namespace sapi
 

sandboxed_api/tools/clang_generator/generator.cc

@@ -201,9 +201,9 @@ bool GeneratorASTVisitor::VisitFunctionDecl(clang::FunctionDecl* decl) {
 
 void GeneratorASTConsumer::HandleTranslationUnit(clang::ASTContext& context) {
   if (!visitor_.TraverseDecl(context.getTranslationUnitDecl())) {
-    ReportFatalError(context.getDiagnostics(),
-                     context.getTranslationUnitDecl()->getBeginLoc(),
-                     "AST traversal exited early.");
+    Report(context.getDiagnostics(),
+           context.getTranslationUnitDecl()->getBeginLoc(),
+           clang::DiagnosticsEngine::Fatal, "AST traversal exited early.");
     return;
   }
 
@@ -220,12 +220,10 @@ void GeneratorASTConsumer::HandleTranslationUnit(clang::ASTContext& context) {
     if (!status.ok()) {
       clang::SourceLocation loc =
           GetDiagnosticLocationFromStatus(status).value_or(func->getBeginLoc());
-      if (absl::IsCancelled(status)) {
-        ReportWarning(context.getDiagnostics(), loc, status.message());
-        continue;
-      }
-      ReportFatalError(context.getDiagnostics(), loc, status.message());
-      break;
+      clang::DiagnosticsEngine::Level level =
+          absl::IsCancelled(status) ? clang::DiagnosticsEngine::Warning
+                                    : clang::DiagnosticsEngine::Error;
+      Report(context.getDiagnostics(), loc, level, status.message());
     }
   }
 }