[clang] [clang-installapi] ] Fix potential null pointer dereference in file enumeration (PR #97900)

[via cfe-commits]

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@@ -51,8 +51,14 @@ llvm::Expected<PathSeq> enumerateFiles(FileManager &FM, StringRef Directory) {
     if (EC)
       return errorCodeToError(EC);
 
+    // Ensure the iterator is valid before dereferencing.
+    if (i == ie)
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smanna12 wrote:

> Why does this make a difference? 

Thanks @cyndyishida for reviews!

>>the same check happens at each iteration of the loop on line 50. There's no mutations on `i` or `ie` between there and this check.

Agreed. I misunderstood the codes! 

https://github.com/llvm/llvm-project/pull/97900