[PATCH] Fix some sparse warnings

Sparse issues some "Using plain integer as NULL pointer" warnings.
Each warning relates to the use of an '{0}' initialiser expression
in the declaration of an 'struct object_info'. The first field of
this structure has pointer type. Thus, in order to suppress these
warnings, we replace the initialiser expression with '{NULL}'.

Signed-off-by: Ramsay Jones <redacted>
---

This was built on the next branch.

ATB,
Ramsay Jones


 sha1_file.c | 2 +-
 streaming.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/sha1_file.c b/sha1_file.c
index 4c2365f..e4ab0a4 100644
--- a/sha1_file.c
+++ b/sha1_file.c

@@ -2440,7 +2440,7 @@ int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi)
 
 int sha1_object_info(const unsigned char *sha1, unsigned long *sizep)
 {
-	struct object_info oi = {0};
+	struct object_info oi = {NULL};
 
 	oi.sizep = sizep;
 	return sha1_object_info_extended(sha1, &oi);

diff --git a/streaming.c b/streaming.c
index cac282f..5710065 100644
--- a/streaming.c
+++ b/streaming.c

@@ -135,7 +135,7 @@ struct git_istream *open_istream(const unsigned char *sha1,
 				 struct stream_filter *filter)
 {
 	struct git_istream *st;
-	struct object_info oi = {0};
+	struct object_info oi = {NULL};
 	const unsigned char *real = lookup_replace_object(sha1);
 	enum input_source src = istream_source(real, type, &oi);
 

-- 
1.8.3

On Thu, Jul 18, 2013 at 09:25:50PM +0100, Ramsay Jones wrote:

Sparse issues some "Using plain integer as NULL pointer" warnings.
Each warning relates to the use of an '{0}' initialiser expression
in the declaration of an 'struct object_info'. The first field of
this structure has pointer type. Thus, in order to suppress these
warnings, we replace the initialiser expression with '{NULL}'.

Signed-off-by: Ramsay Jones <redacted>

Acked-by: Jeff King <redacted>

I thought at first we would need one more for the new callsite I added
in my series, but we use memset() in that instance, so it is fine.

-Peff

Jeff King wrote:

On Thu, Jul 18, 2013 at 09:25:50PM +0100, Ramsay Jones wrote:

quoted

Sparse issues some "Using plain integer as NULL pointer" warnings.
Each warning relates to the use of an '{0}' initialiser expression
in the declaration of an 'struct object_info'. The first field of
this structure has pointer type. Thus, in order to suppress these
warnings, we replace the initialiser expression with '{NULL}'.

Signed-off-by: Ramsay Jones <redacted>

Acked-by: Jeff King <redacted>

I thought at first we would need one more for the new callsite I added
in my series, but we use memset() in that instance, so it is fine.

On an almost unrelated note ... I am now getting the following sparse
warnings:

    pack-revindex.c:105:23: warning: memset with byte count of 262144

This is a little annoying, since there is no way to turn this off. :(
(which I consider a bug in sparse).

Sparse has special-case code to check calls to memset(), memcpy(),
copy_to_user() and copy_from_user(). The code that checks the byte
count argument looks like:

static void check_byte_count(struct instruction *insn, pseudo_t count)
{
        if (!count)
                return;
        if (count->type == PSEUDO_VAL) {
                long long val = count->value;
                if (val <= 0 || val > 100000)
                        warning(insn->pos, "%s with byte count of %lld",
                                show_ident(insn->func->sym->ident), val);
                return;
        }
        /* OK, we could try to do the range analysis here */
}

I will just ignore this for now. ;-)

ATB,
Ramsay Jones

Hi,

Ramsay Jones wrote:

Sparse issues some "Using plain integer as NULL pointer" warnings.
Each warning relates to the use of an '{0}' initialiser expression
in the declaration of an 'struct object_info'. The first field of
this structure has pointer type. Thus, in order to suppress these
warnings, we replace the initialiser expression with '{NULL}'.

I agree that this is worth solving but the fix feels like a move in
the wrong direction.  Before this patch, the initialization says
"= {0}", which basically means "memset it to 0".  Afterward, the
initializer depends on the order of fields in the struct.

How about something like the following?

diff --git i/cache.h w/cache.h
index f2915509..ba028b75 100644
--- i/cache.h
+++ w/cache.h

@@ -1124,6 +1124,7 @@ struct object_info {
 		} packed;
 	} u;
 };
+#define OBJECT_INFO_INIT { NULL, NULL, OI_CACHED, { { NULL, 0, 0 } } }
 extern int sha1_object_info_extended(const unsigned char *, struct object_info *);
 
 /* Dumb servers support */

diff --git i/sha1_file.c w/sha1_file.c
index 6baed676..2d812b8d 100644
--- i/sha1_file.c
+++ w/sha1_file.c

@@ -2421,7 +2421,7 @@ int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi)
 
 int sha1_object_info(const unsigned char *sha1, unsigned long *sizep)
 {
-	struct object_info oi = {0};
+	struct object_info oi = OBJECT_INFO_INIT;
 
 	oi.sizep = sizep;
 	return sha1_object_info_extended(sha1, &oi);

diff --git i/streaming.c w/streaming.c
index cac282f0..b4c40ad9 100644
--- i/streaming.c
+++ w/streaming.c

@@ -135,7 +135,7 @@ struct git_istream *open_istream(const unsigned char *sha1,
 				 struct stream_filter *filter)
 {
 	struct git_istream *st;
-	struct object_info oi = {0};
+	struct object_info oi = OBJECT_INFO_INIT;
 	const unsigned char *real = lookup_replace_object(sha1);
 	enum input_source src = istream_source(real, type, &oi);