[llvm] Add PR check to suggest alternatives to using undef (PR #118506)

[David Spickett via llvm-commits]

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@@ -312,7 +313,84 @@ def format_run(self, changed_files: List[str], args: FormatArgs) -> Optional[str
             return None
 
 
-ALL_FORMATTERS = (DarkerFormatHelper(), ClangFormatHelper())
+class UndefGetFormatHelper(FormatHelper):
+    name = "undef deprecator"
+    friendly_name = "undef deprecator"
+
+    @property
+    def instructions(self) -> str:
+        return " ".join(f"'{c}'" for c in self.cmd)
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DavidSpickett wrote:

What's the `''` quoting for? If it's shell escaping you could use https://docs.python.org/3/library/shlex.html#shlex.quote.

https://github.com/llvm/llvm-project/pull/118506