fix potential invalid mmap call and uninitialized file size#4559
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richardsonnick wants to merge 1 commit intofacebook:devfrom
Open
fix potential invalid mmap call and uninitialized file size#4559richardsonnick wants to merge 1 commit intofacebook:devfrom
richardsonnick wants to merge 1 commit intofacebook:devfrom
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Fixes a warning from Clang 21 (unix.StdCLibraryFunctions) where mmap() could be called with a length of 0 if the dictionary file is empty. Mapping a zero-length range is undefined behavior under POSIX. - Added guard for zero-length dictionary files.
terrelln
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Feb 27, 2026
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One minor change, otherwise looks good. Thanks for the PR!
Comment on lines
+1054
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+1056
| if (fileSize == (unsigned long long)-1) { | ||
| EXM_THROW(35, "Could not determine size of dictionary %s", fileName); | ||
| } |
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Can you move this check up to just after line 1044, because the flow should never reach here, due to the check on 1046.
And please also check against UTIL_FILESIZE_UNKNOWN rather than -1.
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Fixes a warning from Clang 21 (unix.StdCLibraryFunctions) where mmap() could be called with a length of 0 if the dictionary file is empty. Mapping a zero-length range is undefined behavior under POSIX.
Reported-by: Clang 21 Static Analyzer