[clang-tidy] warnings-as-error no longer exits with ErrorCount

[njames93]

Summary

When using -warnings-as-errors, If there are any warnings promoted to errors, clang-tidy exits with the number of warnings. This really isn't needed and can cause issues when the number of warnings doesn't fit into 8 bits as POSIX terminals aren't designed to handle more than that.
This addresses https://bugs.llvm.org/show_bug.cgi?id=46305.

Bug originally added in D15528

[lebedev.ri]

lgtm

[aaron.ballman]

LGTM unless @jroelofs has a reason why the code was originally written that way, but can you add test coverage for it?

[njames93]

In D81953#2096388, @aaron.ballman wrote:

LGTM unless @jroelofs has a reason why the code was originally written that way, but can you add test coverage for it?

How would you suggest I add test coverage for this, afaik llvm-lit doesn't seem to handle checking specific exit codes, only whether is was 0 or not.
There are already test cases for a non-zero exit code with -warnings-as-errors.

[aaron.ballman]

In D81953#2096635, @njames93 wrote:

In D81953#2096388, @aaron.ballman wrote:

LGTM unless @jroelofs has a reason why the code was originally written that way, but can you add test coverage for it?

How would you suggest I add test coverage for this, afaik llvm-lit doesn't seem to handle checking specific exit codes, only whether is was 0 or not.
There are already test cases for a non-zero exit code with -warnings-as-errors.

If lit doesn't provide a way to do this, I don't insist. I was thinking you'd have a way to use the lit shell to compare against the return value since it had the ability to test against nonzero or not.

clang-tools-extra/clang-tidy/tool/ClangTidyMain.cpp

int clangTidyMain(int argc, const char **argv) {
   }
 
   if (WErrorCount) {
     if (!Quiet) {
       StringRef Plural = WErrorCount == 1 ? "" : "s";
       llvm::errs() << WErrorCount << " warning" << Plural << " treated as error"
                    << Plural << "\n";
     }
-    return WErrorCount;
+    return 1;
   }
 
   if (FoundErrors) {
     // TODO: Figure out when zero exit code should be used with -fix-errors:
     //   a. when a fix has been applied for an error
     //   b. when a fix has been applied for all errors
     //   c. some other condition.
     // For now always returning zero when -fix-errors is used.