[clang-tools-extra] [clang-doc] Refactor error handling to use ExitOnError (PR #141699)

[Samarth Narang via cfe-commits]

https://github.com/snarang181 updated https://github.com/llvm/llvm-project/pull/141699

>From b2dc4f8a50d86ecdc5fd27fedd7efde5c6882df5 Mon Sep 17 00:00:00 2001
From: Samarth Narang <snarang at umass.edu>
Date: Tue, 27 May 2025 21:32:41 -0400
Subject: [PATCH 1/2] [clang-doc] Refactor error handling to use ExitOnError

This patch replaces manual error checks and exit() calls in clang-doc
with llvm::ExitOnError for consistency and maintainability.

No functional changes to outputs or APIs.
---
 .../clang-doc/tool/ClangDocMain.cpp           | 32 ++++++-------------
 1 file changed, 10 insertions(+), 22 deletions(-)

diff --git a/clang-tools-extra/clang-doc/tool/ClangDocMain.cpp b/clang-tools-extra/clang-doc/tool/ClangDocMain.cpp
index 8e8f7053a8f87..e7efa4b15d80f 100644
--- a/clang-tools-extra/clang-doc/tool/ClangDocMain.cpp
+++ b/clang-tools-extra/clang-doc/tool/ClangDocMain.cpp
@@ -49,6 +49,7 @@
 using namespace clang::ast_matchers;
 using namespace clang::tooling;
 using namespace clang;
+static llvm::ExitOnError ExitOnErr;
 
 static llvm::cl::extrahelp CommonHelp(CommonOptionsParser::HelpMessage);
 static llvm::cl::OptionCategory ClangDocCategory("clang-doc options");
@@ -236,6 +237,8 @@ int main(int argc, const char **argv) {
   llvm::sys::PrintStackTraceOnErrorSignal(argv[0]);
   std::error_code OK;
 
+  ExitOnErr.setBanner("clang-doc error: ");
+
   const char *Overview =
       R"(Generates documentation from source code and comments.
 
@@ -259,11 +262,7 @@ Example usage for a project using a compile commands database:
   // Fail early if an invalid format was provided.
   std::string Format = getFormatString();
   llvm::outs() << "Emiting docs in " << Format << " format.\n";
-  auto G = doc::findGeneratorByName(Format);
-  if (!G) {
-    llvm::errs() << toString(G.takeError()) << "\n";
-    return 1;
-  }
+  auto G = ExitOnErr(doc::findGeneratorByName(Format));
 
   ArgumentsAdjuster ArgAdjuster;
   if (!DoxygenOnly)
@@ -284,10 +283,7 @@ Example usage for a project using a compile commands database:
       {UserStylesheets.begin(), UserStylesheets.end()}};
 
   if (Format == "html") {
-    if (auto Err = getHtmlAssetFiles(argv[0], CDCtx)) {
-      llvm::errs() << toString(std::move(Err)) << "\n";
-      return 1;
-    }
+    ExitOnErr(getHtmlAssetFiles(argv[0], CDCtx));
   }
 
   // Mapping phase
@@ -300,7 +296,7 @@ Example usage for a project using a compile commands database:
                       "these files and continue:\n"
                    << toString(std::move(Err)) << "\n";
     else {
-      llvm::errs() << toString(std::move(Err)) << "\n";
+      ExitOnErr(std::move(Err));
       return 1;
     }
   }
@@ -371,22 +367,14 @@ Example usage for a project using a compile commands database:
   sortUsrToInfo(USRToInfo);
 
   // Ensure the root output directory exists.
-  if (std::error_code Err = llvm::sys::fs::create_directories(OutDirectory);
-      Err != std::error_code()) {
-    llvm::errs() << "Failed to create directory '" << OutDirectory << "'\n";
-    return 1;
-  }
+  ExitOnErr(
+      llvm::errorCodeToError(llvm::sys::fs::create_directories(OutDirectory)));
 
   // Run the generator.
   llvm::outs() << "Generating docs...\n";
-  if (auto Err =
-          G->get()->generateDocs(OutDirectory, std::move(USRToInfo), CDCtx)) {
-    llvm::errs() << toString(std::move(Err)) << "\n";
-    return 1;
-  }
-
+  ExitOnErr(G->generateDocs(OutDirectory, std::move(USRToInfo), CDCtx));
   llvm::outs() << "Generating assets for docs...\n";
-  Err = G->get()->createResources(CDCtx);
+  Err = G->createResources(CDCtx);
   if (Err) {
     llvm::outs() << "warning: " << toString(std::move(Err)) << "\n";
   }

>From 51238bcaf1a6450eb2b7dfbc259a1d7c4bba0a17 Mon Sep 17 00:00:00 2001
From: Samarth Narang <snarang at umass.edu>
Date: Wed, 28 May 2025 18:47:17 -0400
Subject: [PATCH 2/2] Addressing PR feedback

---
 clang-tools-extra/clang-doc/tool/ClangDocMain.cpp    | 12 +++++++++---
 .../test/clang-doc/invalid-file-error.test           |  4 ++++
 2 files changed, 13 insertions(+), 3 deletions(-)
 create mode 100644 clang-tools-extra/test/clang-doc/invalid-file-error.test

diff --git a/clang-tools-extra/clang-doc/tool/ClangDocMain.cpp b/clang-tools-extra/clang-doc/tool/ClangDocMain.cpp
index e7efa4b15d80f..78ad1521397e6 100644
--- a/clang-tools-extra/clang-doc/tool/ClangDocMain.cpp
+++ b/clang-tools-extra/clang-doc/tool/ClangDocMain.cpp
@@ -49,7 +49,6 @@
 using namespace clang::ast_matchers;
 using namespace clang::tooling;
 using namespace clang;
-static llvm::ExitOnError ExitOnErr;
 
 static llvm::cl::extrahelp CommonHelp(CommonOptionsParser::HelpMessage);
 static llvm::cl::OptionCategory ClangDocCategory("clang-doc options");
@@ -128,6 +127,8 @@ static llvm::cl::opt<OutputFormatTy>
                llvm::cl::init(OutputFormatTy::yaml),
                llvm::cl::cat(ClangDocCategory));
 
+static llvm::ExitOnError ExitOnErr;
+
 static std::string getFormatString() {
   switch (FormatEnum) {
   case OutputFormatTy::yaml:
@@ -367,8 +368,13 @@ Example usage for a project using a compile commands database:
   sortUsrToInfo(USRToInfo);
 
   // Ensure the root output directory exists.
-  ExitOnErr(
-      llvm::errorCodeToError(llvm::sys::fs::create_directories(OutDirectory)));
+  if (std::error_code Err = llvm::sys::fs::create_directories(OutDirectory);
+      Err != std::error_code()) {
+    ExitOnErr(llvm::createStringError(
+        llvm::inconvertibleErrorCode(), "Failed to create directory '%s': %s",
+        OutDirectory.c_str(), Err.message().c_str()));
+  }
+
 
   // Run the generator.
   llvm::outs() << "Generating docs...\n";
diff --git a/clang-tools-extra/test/clang-doc/invalid-file-error.test b/clang-tools-extra/test/clang-doc/invalid-file-error.test
new file mode 100644
index 0000000000000..8d391842aa452
--- /dev/null
+++ b/clang-tools-extra/test/clang-doc/invalid-file-error.test
@@ -0,0 +1,4 @@
+// RUN: not clang-doc %S/Inputs/basic-project/src/Circle.cpp -output=/root/docs 2>&1 | FileCheck %s
+
+// CHECK: clang-doc error: Failed to create directory
+