[clang-tidy] Add null-checking in Use designated Initializer check

[GTaf]

Part of #219739

This null check should avoid null dereferencing crash in the Use designated Initializer check.

AI has been used in this contribution to understand the code as I'm a beginner to the codebase. The problem understanding and proposed fix is mine.

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@llvm/pr-subscribers-clang-tools-extra

@llvm/pr-subscribers-clang-tidy

Author: GTaf

Changes

Trying to fix #219739

---

Full diff: https://github.com/llvm/llvm-project/pull/220093.diff

1 Files Affected:

• (modified) clang-tools-extra/clang-tidy/modernize/UseDesignatedInitializersCheck.cpp (+2-1)

diff --git a/clang-tools-extra/clang-tidy/modernize/UseDesignatedInitializersCheck.cpp b/clang-tools-extra/clang-tidy/modernize/UseDesignatedInitializersCheck.cpp
index 5874c061d299f..696e6f40d66c8 100644
--- a/clang-tools-extra/clang-tidy/modernize/UseDesignatedInitializersCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/UseDesignatedInitializersCheck.cpp
@@ -17,6 +17,7 @@
 #include "clang/ASTMatchers/ASTMatchersMacros.h"
 #include "clang/Basic/Diagnostic.h"
 #include "clang/Lex/Lexer.h"
+#include "llvm/Support/Casting.h"
 
 using namespace clang::ast_matchers;
 
@@ -42,7 +43,7 @@ static constexpr bool StrictCppStandardComplianceDefault = true;
 
 static unsigned getNumberOfDesignated(const InitListExpr *SyntacticInitList) {
   return llvm::count_if(*SyntacticInitList, [](auto *InitExpr) {
-    return isa<DesignatedInitExpr>(InitExpr);
+    return llvm::isa_and_nonnull<DesignatedInitExpr>(InitExpr);
   });
 }
 

[EugeneZelenko]

Please mention changes in Release Notes.

[vbvictor]

Please mention changes in Release Notes.

And tests

[zeyi2]

The code part change LGTM, one nit comment below

[zeyi2]

Looks like unnecessary include, please see https://llvm.org/docs/CodingStandards.html#include-as-little-as-possible

[zeyi2]

Also I removed "Fixes #219739", since this PR only addresses the modernize-use-designated-initializers crash. The other crash in readability-trailing-comma probably needs a separate PR.

[GTaf]

Thanks for your feedback. I'm working on your assigned tasks.

Making a relevant test is a bit challenging to me has the issue is to say that an invalid code that use to crash the binary now just show the correct error. I'm looking into it.

[zeyi2]

Making a relevant test is a bit challenging to me has the issue is to say that an invalid code that use to crash the binary now just show the correct error. I'm looking into it.

I think you can use invalid code with -expect-clang-tidy-error in the // RUN line.

See ./clang-tools-extra/test/clang-tidy/checkers/readability/isolate-declaration-no-infinite-loop.cpp as a reference :)

// RUN: %check_clang_tidy -expect-clang-tidy-error %s readability-isolate-declaration %t

int main(){
  int a, b
  // CHECK-MESSAGES: [[@LINE-1]]:3: warning: multiple declarations in a single statement reduces readability
  // CHECK-MESSAGES: [[@LINE-2]]:11: error: expected ';' at end of declaration [clang-diagnostic-error]
}

[EugeneZelenko]

Please keep alphabetical order (by check name) in this list.

[EugeneZelenko]

This is implementation detail. Should be something user-facing.

[EugeneZelenko]

Should be before modernize-use-noexcept.

[GTaf]

I believe I did all you pinpointed, thank you very much for your guidance and patience.
All tests runned fine from both check-llvm and check-llvm-unit on my computer.

Please let me know anything that still needs to be fixed