[clang-format] Print the names of unfound files in error messages

[owenca]

Also fix the return status when -i is used with reading from stdin.

Fixes #113631.

[llvmbot]

@llvm/pr-subscribers-clang-format

Author: Owen Pan (owenca)

Changes

Fixes #113631.

---

Full diff: https://github.com/llvm/llvm-project/pull/113640.diff

2 Files Affected:

• (added) clang/test/Format/error-unfound-files.cpp (+7)
• (modified) clang/tools/clang-format/ClangFormat.cpp (+1-1)

diff --git a/clang/test/Format/error-unfound-files.cpp b/clang/test/Format/error-unfound-files.cpp
new file mode 100644
index 00000000000000..3923c8d097443c
--- /dev/null
+++ b/clang/test/Format/error-unfound-files.cpp
@@ -0,0 +1,7 @@
+// RUN: rm -f a.c b.c
+
+// RUN: not clang-format a.c b.c 2>&1 | FileCheck %s
+// CHECK: a.c:
+// CHECK-NEXT: b.c:
+
+// rm -f a.c b.c
diff --git a/clang/tools/clang-format/ClangFormat.cpp b/clang/tools/clang-format/ClangFormat.cpp
index 96fb85e99bf5f0..7c54462b3795dd 100644
--- a/clang/tools/clang-format/ClangFormat.cpp
+++ b/clang/tools/clang-format/ClangFormat.cpp
@@ -419,7 +419,7 @@ static bool format(StringRef FileName, bool ErrorOnIncompleteFormat = false) {
           ? MemoryBuffer::getFileAsStream(FileName)
           : MemoryBuffer::getFileOrSTDIN(FileName, /*IsText=*/true);
   if (std::error_code EC = CodeOrErr.getError()) {
-    errs() << EC.message() << "\n";
+    errs() << FileName << ": " << EC.message() << "\n";
     return true;
   }
   std::unique_ptr<llvm::MemoryBuffer> Code = std::move(CodeOrErr.get());