[clang-format] Pass a TextDiagnosticPrinter when we can not create tempory file.

[Et7f3]

Summary

Reproduction:
$ mkdir folder
$ echo ' ' > folder/file.c
$ sudo chown -R root folder
$ clang-format -i root/file.c

Before the clang-format abort now clang-format explain why it fail.

Ask: They are other DiagnosticConsumer without client should we update the other ?
Also we don't know how to create test that play with user permission.

Co-authored-by: "tartine8" <[e-mail]>

[Et7f3]

Add a reproduction case in commit message.

[xgupta]

Thanks for the patch @Et7f3! I tested it locally and can reproduce it with cat folder/file.c
int main()
{
return 0;
}
And indeed the patch also solved the crash issue and emit a correct error message but I am not sure about its implementation, I think @MyDeveloperDay can best review this patch.

There is a nit in the patch summary, clang-format -i root/file.c should be clang-format -i folder/file.c.

[MyDeveloperDay]

Including clangFrontend has been discourage many times before, we don't want to add that to the list of dependencies please see D90121: clang-format: Add a consumer to diagnostics engine

[MyDeveloperDay]

also D68554: [clang-format] Proposal for clang-format to give compiler style warnings

[Et7f3]

Mb I just looked in driver how to setup diagnostics (which included frontend).

Ok so I see 2 options:

• move TextDiagnosticsPrinter in clangBasic
• Use SMDiagnostic like clang/tools/clang-format/ClangFormat.cpp:324 but it seem to need a SMLoc so not really adapted.

[MyDeveloperDay]

Yeah, I made the almost identical change but got some push back on it extending the dependencies (I think it also meant that the clang-format target needed alot more source to be compiled)

Dinking around in clangBasic is probably outside my pay grade ;-)

[MyDeveloperDay]

This is no longer needed, please abanson

clang/tools/clang-format/CMakeLists.txt

 set(LLVM_LINK_COMPONENTS support)
 
 add_clang_tool(clang-format
   ClangFormat.cpp
   )
 
 set(CLANG_FORMAT_LIB_DEPS
   clangBasic
   clangFormat
+  clangFrontend
   clangRewrite
   clangToolingCore
   )
 
 clang_target_link_libraries(clang-format
   PRIVATE
   ${CLANG_FORMAT_LIB_DEPS}
   )

clang/tools/clang-format/ClangFormat.cpp

 //===-- clang-format/ClangFormat.cpp - Clang format tool ------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
 /// This file implements a clang-format tool that automatically formats
 /// (fragments of) C++ code.
 ///
 //===----------------------------------------------------------------------===//
 
 #include "clang/Basic/Diagnostic.h"
 #include "clang/Basic/DiagnosticOptions.h"
 #include "clang/Basic/FileManager.h"
 #include "clang/Basic/SourceManager.h"
 #include "clang/Basic/Version.h"
 #include "clang/Format/Format.h"
+#include "clang/Frontend/TextDiagnosticPrinter.h"
 #include "clang/Rewrite/Core/Rewriter.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/InitLLVM.h"
 #include "llvm/Support/Process.h"
 
 using namespace llvm;
 using clang::tooling::Replacements;
if (DryRun) {
       return emitReplacementWarnings(Replaces, AssumedFileName, Code);
     } else {
       outputXML(Replaces, FormatChanges, Status, Cursor, CursorPosition);
     }
   } else {
     IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> InMemoryFileSystem(
         new llvm::vfs::InMemoryFileSystem);
     FileManager Files(FileSystemOptions(), InMemoryFileSystem);
+    IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts = new DiagnosticOptions;
+    TextDiagnosticPrinter *DiagClient =
+        new TextDiagnosticPrinter(llvm::errs(), &*DiagOpts);
     DiagnosticsEngine Diagnostics(
         IntrusiveRefCntPtr<DiagnosticIDs>(new DiagnosticIDs),
-        new DiagnosticOptions);
+        &*DiagOpts, DiagClient);
     SourceManager Sources(Diagnostics, Files);
     FileID ID = createInMemoryFile(AssumedFileName, *Code, Sources, Files,
                                    InMemoryFileSystem.get());
     Rewriter Rewrite(Sources, LangOptions());
     tooling::applyAllReplacements(Replaces, Rewrite);
     if (Inplace) {
       if (Rewrite.overwriteChangedFiles())
         return true;