archive-tar: fix a sparse 'constant too large' warning

Commit dddbad728c ("timestamp_t: a new data type for timestamps", 26-04-2017) introduced a new typedef 'timestamp_t', as a synonym for an unsigned long, which was used at the time to represent timestamps in git. A later commit 28f4aee3fb ("use uintmax_t for timestamps", 26-04-2017) changed the typedef to use an 'uintmax_t' for the timestamp representation type. When building on a 32-bit Linux system, sparse complains that a constant (USTAR_MAX_MTIME) used to detect a 'far-future mtime' timestamp, is too large; 'warning: constant 077777777777UL is so big it is unsigned long long' on lines 335 and 338 of archive-tar.c. Note that both gcc and clang only issue a warning if this constant is used in a context that requires an 'unsigned long' (rather than an uintmax_t). (Since TIME_MAX is no longer equal to 0xFFFFFFFF, even on a 32-bit system, the macro USTAR_MAX_MTIME is set to 077777777777UL, which cannot be represented as an 'unsigned long' constant). In order to suppress the warning, change the definition of the macro constant USTAR_MAX_MTIME to use an 'ULL' type suffix. In a similar vein, on systems which use a 64-bit representation of the 'unsigned long' type, the USTAR_MAX_SIZE constant macro is defined with the value 077777777777ULL. Although this does not cause any warning messages to be issued, it would be more appropriate for this constant to use an 'UL' type suffix rather than 'ULL'. Signed-off-by: Ramsay Jones <ramsay@ramsayjones.plus.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Ramsay Jones committed May 8, 2017 at 21:34 UTC 3f789719a65bfa6c302e8f794847a3eb69b6881b
1 file changed +2 -2
archive-tar.c
+2 -2
@@ -28,12 +28,12 @@ static int write_tar_filter_archive(const struct archiver *ar,
28 #if ULONG_MAX == 0xFFFFFFFF
29 #define USTAR_MAX_SIZE ULONG_MAX
30 #else
31 -#define USTAR_MAX_SIZE 077777777777ULL
31 +#define USTAR_MAX_SIZE 077777777777UL
32 #endif
33 #if TIME_MAX == 0xFFFFFFFF
34 #define USTAR_MAX_MTIME TIME_MAX
35 #else
36 -#define USTAR_MAX_MTIME 077777777777UL
36 +#define USTAR_MAX_MTIME 077777777777ULL
37 #endif
38
39 /* writes out the whole block, but only if it is full */