Subject: [PATCH v3] REFTABLE_REALLOC_ARRAY: remove this unsafe yet unused macro

From: "Lidong Yan via GitGitGadget" <[email-masked]>
Date: Fri, 09 May 2025 07:44:46 +0000

From: Lidong Yan <[email-masked]>

REFTABLE_REALLOC_ARRAY will cause memory leak if realloc failed.
Since it is unused, remove this unsafe macro.

Signed-off-by: Lidong Yan <[email-masked]>
---
    REFTABLE_REALLOC_ARRAY: fix potential memory leak if realloc failed
    
    REFTABLE_REALLOC_ARRAY doesn't free origin pointer when reftable_realloc
    failed. This leak can be fixed by add a free(x) before set x to NULL.

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-1955%2Fbrandb97%2Ffix-REFTABLE-REALLOC-leak-v3
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-1955/brandb97/fix-REFTABLE-REALLOC-leak-v3
Pull-Request: https://github.com/git/git/pull/1955

Range-diff vs v2:

 1:  6cc191f9db8 ! 1:  107f9ce3bd0 REFTABLE_REALLOC_ARRAY: remove this unsafe yet unused macro
     @@ Commit message
      
       ## reftable/basics.h ##
      @@ reftable/basics.h: static inline int reftable_alloc_size(size_t nelem, size_t elsize, size_t *out)
     - 			(x) = reftable_malloc(alloc_size); \
       		} \
       	} while (0)
     --#define REFTABLE_CALLOC_ARRAY(x, alloc) (x) = reftable_calloc((alloc), sizeof(*(x)))
     + #define REFTABLE_CALLOC_ARRAY(x, alloc) (x) = reftable_calloc((alloc), sizeof(*(x)))
      -#define REFTABLE_REALLOC_ARRAY(x, alloc) do { \
      -		size_t alloc_size; \
      -		if (reftable_alloc_size(sizeof(*(x)), (alloc), &alloc_size) < 0) { \
     @@ reftable/basics.h: static inline int reftable_alloc_size(size_t nelem, size_t el
      -			(x) = reftable_realloc((x), alloc_size); \
      -		} \
      -	} while (0)
     -+#define REFTABLE_CALLOC_ARRAY(x, alloc) \
     -+	(x) = reftable_calloc((alloc), sizeof(*(x)))
       
       static inline void *reftable_alloc_grow(void *p, size_t nelem, size_t elsize,
       					size_t *allocp)

 reftable/basics.h | 9 ---------
 1 file changed, 9 deletions(-)

diff --git a/reftable/basics.h b/reftable/basics.h
index d8888c12629..1674a6f8b80 100644
--- a/reftable/basics.h
+++ b/reftable/basics.h
@@ -200,15 +200,6 @@ static inline int reftable_alloc_size(size_t nelem, size_t elsize, size_t *out)
 		} \
 	} while (0)
 #define REFTABLE_CALLOC_ARRAY(x, alloc) (x) = reftable_calloc((alloc), sizeof(*(x)))
-#define REFTABLE_REALLOC_ARRAY(x, alloc) do { \
-		size_t alloc_size; \
-		if (reftable_alloc_size(sizeof(*(x)), (alloc), &alloc_size) < 0) { \
-			errno = ENOMEM; \
-			(x) = NULL; \
-		} else { \
-			(x) = reftable_realloc((x), alloc_size); \
-		} \
-	} while (0)
 
 static inline void *reftable_alloc_grow(void *p, size_t nelem, size_t elsize,
 					size_t *allocp)

base-commit: 6f84262c44a89851c3ae5a6e4c1a9d06b2068d75
-- 
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