Fix -Wdiscarded-qualifiers warning in kms_request.c#2354
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Remove unnecessary (const char *) casts on the strchr arguments in
parse_query_params. In C23 (the default for GCC 15) strchr is
const-generic: passing a const char * makes it return const char *,
which cannot be assigned to the non-const 'equals' and 'amp' pointers:
kms/kms_request.c: In function 'parse_query_params':
kms/kms_request.c:35:14: warning: assignment discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
35 | equals = strchr ((const char *) p, '=');
| ^
kms/kms_request.c:40:11: warning: assignment discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
40 | amp = strchr ((const char *) equals, '&');
| ^
Since p and equals are already plain char *, the casts serve no
purpose and dropping them is warning-free on both old and new
compilers.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
jeroen
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Jul 20, 2026
In C23 (default for GCC 15) strchr is const-generic, so the explicit (const char *) casts made it return const char *, which cannot be assigned to the non-const 'equals' and 'amp' pointers. Upstreamed as mongodb/mongo-c-driver#2354 Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
kevinAlbs
self-requested a review
July 20, 2026 16:39
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Thanks for the PR @jeroen. This file is copied from libmongocrypt. Applied this fix in mongodb/libmongocrypt#1206 and can update the copy to the latest libmongocrypt sources after merging. |
Collaborator
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Closing in favor of #2355 which updates the kms-message sources to include mongodb/libmongocrypt#1206. Thanks again @jeroen for bringing this to our attention. |
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Thank you! |
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This fixes a (problematic)
-Wdiscarded-qualifierswarning that we get in the R bindings ongcc-16:AI summary: In C23 (the default language standard for GCC 15),
strchris const-generic: when passed aconst char *it returns aconst char *. The explicit(const char *)casts inparse_query_paramstherefore make the result unassignable to the non-constequalsandamppointers.Since
pandequalsare already plainchar *, the casts serve no purpose; removing them is warning-free on both old and new compilers.