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

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

[Ramsay Jones]

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 to use an 'ULL' type suffix.

Signed-off-by: Ramsay Jones <ramsay@ramsayjones.plus.com>
---

Hi Junio,

I try to build git on 32-bit Linux about once a week (but it can
sometimes be less often than that!). During tonight's build sparse
chirped at me while building the 'next' branch.

This patch was built on top of next.

ATB,
Ramsay Jones

 archive-tar.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/archive-tar.c b/archive-tar.c
index 319a5b1c7..6dddc0cff 100644
--- a/archive-tar.c
+++ b/archive-tar.c
@@ -33,7 +33,7 @@ static int write_tar_filter_archive(const struct archiver *ar,
 #if TIME_MAX == 0xFFFFFFFF
 #define USTAR_MAX_MTIME TIME_MAX
 #else
-#define USTAR_MAX_MTIME 077777777777UL
+#define USTAR_MAX_MTIME 077777777777ULL
 #endif
 
 /* writes out the whole block, but only if it is full */
-- 
2.12.0

Re: [PATCH] archive-tar: fix a sparse 'constant too large' warning

[Johannes Schindelin]

Hi Ramsay,

On Thu, 4 May 2017, Ramsay Jones wrote:

> diff --git a/archive-tar.c b/archive-tar.c
> index 319a5b1c7..6dddc0cff 100644
> --- a/archive-tar.c
> +++ b/archive-tar.c
> @@ -33,7 +33,7 @@ static int write_tar_filter_archive(const struct archiver *ar,
>  #if TIME_MAX == 0xFFFFFFFF
>  #define USTAR_MAX_MTIME TIME_MAX
>  #else
> -#define USTAR_MAX_MTIME 077777777777UL
> +#define USTAR_MAX_MTIME 077777777777ULL
>  #endif
>  

Funny. This problem was pointed out by Hannes Sixt (IIRC) and I fixed this
very thing in v6.

Except I did not. I changed the wrong constant! Instead of
USTAR_MAX_MTIME, I adjusted USTAR_MAX_SIZE. D'oh.

I just saw that my patch series already hit `next`, so I fear you are
right that we need a follow-up patch. Maybe we want this diff, though?

-- snipsnap --
diff --git a/archive-tar.c b/archive-tar.c
index 319a5b1c7cd..073e60ebd3c 100644
--- a/archive-tar.c
+++ b/archive-tar.c
@@ -28,12 +28,12 @@ static int write_tar_filter_archive(const struct archiver *ar,
 #if ULONG_MAX == 0xFFFFFFFF
 #define USTAR_MAX_SIZE ULONG_MAX
 #else
-#define USTAR_MAX_SIZE 077777777777ULL
+#define USTAR_MAX_SIZE 077777777777UL
 #endif
 #if TIME_MAX == 0xFFFFFFFF
 #define USTAR_MAX_MTIME TIME_MAX
 #else
-#define USTAR_MAX_MTIME 077777777777UL
+#define USTAR_MAX_MTIME 077777777777ULL
 #endif
 
 /* writes out the whole block, but only if it is full */

Re: [PATCH] archive-tar: fix a sparse 'constant too large' warning

[Ramsay Jones]

On 04/05/17 10:26, Johannes Schindelin wrote:
> Hi Ramsay,
> 
> On Thu, 4 May 2017, Ramsay Jones wrote:
> 
>> diff --git a/archive-tar.c b/archive-tar.c
>> index 319a5b1c7..6dddc0cff 100644
>> --- a/archive-tar.c
>> +++ b/archive-tar.c
>> @@ -33,7 +33,7 @@ static int write_tar_filter_archive(const struct archiver *ar,
>>  #if TIME_MAX == 0xFFFFFFFF
>>  #define USTAR_MAX_MTIME TIME_MAX
>>  #else
>> -#define USTAR_MAX_MTIME 077777777777UL
>> +#define USTAR_MAX_MTIME 077777777777ULL
>>  #endif
>>  
> 
> Funny. This problem was pointed out by Hannes Sixt (IIRC) and I fixed this
> very thing in v6.
> 
> Except I did not. I changed the wrong constant! Instead of
> USTAR_MAX_MTIME, I adjusted USTAR_MAX_SIZE. D'oh.

Ah, I did wonder about that.

> I just saw that my patch series already hit `next`, so I fear you are
> right that we need a follow-up patch. Maybe we want this diff, though?
> 
> -- snipsnap --
> diff --git a/archive-tar.c b/archive-tar.c
> index 319a5b1c7cd..073e60ebd3c 100644
> --- a/archive-tar.c
> +++ b/archive-tar.c
> @@ -28,12 +28,12 @@ static int write_tar_filter_archive(const struct archiver *ar,
>  #if ULONG_MAX == 0xFFFFFFFF
>  #define USTAR_MAX_SIZE ULONG_MAX
>  #else
> -#define USTAR_MAX_SIZE 077777777777ULL
> +#define USTAR_MAX_SIZE 077777777777UL

Sure, I can add this. (Although, I don't think it actually
matters).

Hmm, unless somebody objects in the meantime, I will re-roll
the patch (tomorrow, it's late!).

>  #endif
>  #if TIME_MAX == 0xFFFFFFFF
>  #define USTAR_MAX_MTIME TIME_MAX
>  #else
> -#define USTAR_MAX_MTIME 077777777777UL
> +#define USTAR_MAX_MTIME 077777777777ULL
>  #endif
>  
>  /* writes out the whole block, but only if it is full */
> 

ATB,
Ramsay Jones

Re: [PATCH] archive-tar: fix a sparse 'constant too large' warning

[Junio C Hamano]

Ramsay Jones <ramsay@ramsayjones.plus.com> writes:

> Sure, I can add this. (Although, I don't think it actually
> matters).
>
> Hmm, unless somebody objects in the meantime, I will re-roll
> the patch (tomorrow, it's late!).

Thanks.