Merge branch 'jn/size-t-casted-to-off-t-fix'

gitster · gitster · commit d6e35a2644d6 · 2021-06-10T12:04:23.000+09:00
Rewrite code that triggers undefined behaiour warning.

* jn/size-t-casted-to-off-t-fix:
  xsize_t: avoid implementation defined behavior when len &lt; 0
diff --git a/git-compat-util.h b/git-compat-util.h
@@ -986,11 +986,9 @@ static inline char *xstrdup_or_null(const char *str)
 
 static inline size_t xsize_t(off_t len)
 {
-	size_t size = (size_t) len;
-
-	if (len != (off_t) size)
+	if (len < 0 || (uintmax_t) len > SIZE_MAX)
 		die("Cannot handle files this big");
-	return size;
+	return (size_t) len;
 }
 
 __attribute__((format (printf, 3, 4)))

Original file line number	Diff line number	Diff line change
`@@ -986,11 +986,9 @@ static inline char xstrdup_or_null(const char str)`
`986`	`986`
`987`	`987`	`static inline size_t xsize_t(off_t len)`
`988`	`988`	`{`
`989`		`- size_t size = (size_t) len;`
`990`		`-`
`991`		`- if (len != (off_t) size)`
	`989`	`+ if (len < 0 \|\| (uintmax_t) len > SIZE_MAX)`
`992`	`990`	`die("Cannot handle files this big");`
`993`		`- return size;`
	`991`	`+ return (size_t) len;`
`994`	`992`	`}`
`995`	`993`
`996`	`994`	`__attribute__((format (printf, 3, 4)))`