Re: [PATCH] fmt-merge-msg: show those involved in a merged series

On Thu, Mar 8, 2012 at 2:18 PM, Junio C Hamano [off-list ref] wrote:

René Scharfe [off-list ref] writes:

quoted

Am 07.03.2012 22:59, schrieb Junio C Hamano:

quoted

René Scharfe[off-list ref]  writes:

quoted

Am 05.03.2012 22:34, schrieb Junio C Hamano:

quoted

+#define util_as_int(elem) ((intptr_t)((elem)->util))

Something that actually returns an int would fit the name better. ;)

The particular type would not matter to the callers of the helper
macro, would it?

Three of the five callers introduced in that commit cast the result to
int and the remaining two don't care, so it actually does seem to
matter for most of them, strictly speaking.  When I see a nit, I can't
resist the urge to pick it, apparently.

Unfortunately, replacing intptr_t with int or casting the above
again as int will result in

builtin/fmt-merge-msg.c: In function 'record_person':
builtin/fmt-merge-msg.c:213: error: cast to pointer from integer of different size

So...

Out of the frying pan, into the fire...

   builtin/fmt-merge-msg.c: In function ‘record_person’:
   builtin/fmt-merge-msg.c:213:34: warning: cast from pointer to
integer of different size [-Wpointer-to-int-cast]
   builtin/fmt-merge-msg.c: In function ‘cmp_string_list_util_as_int’:
   builtin/fmt-merge-msg.c:219:9: warning: cast from pointer to
integer of different size [-Wpointer-to-int-cast]
   builtin/fmt-merge-msg.c:219:26: warning: cast from pointer to
integer of different size [-Wpointer-to-int-cast]
   builtin/fmt-merge-msg.c: In function ‘add_people_count’:
   builtin/fmt-merge-msg.c:229:8: warning: cast from pointer to
integer of different size [-Wpointer-to-int-cast]
   builtin/fmt-merge-msg.c:231:8: warning: cast from pointer to
integer of different size [-Wpointer-to-int-cast]
   builtin/fmt-merge-msg.c:235:8: warning: cast from pointer to
integer of different size [-Wpointer-to-int-cast]

I see slightly different code in pu than in next, but it produces the
same warnings on my 64-bit Linux machine.

Here's a fix against next:

-- >8 --

Subject: [PATCH] Appease compiler pedantry with an extra cast

Recently git repurposed a pointer as an integer to hold some
counter which git fancies.

Casting directly from 'pointer' to 'int' ((int)(void*)&x) causes a
possible size mismatch because pointers can be bigger than ints.
In such a situation, the compiler complains:

   warning: cast from pointer to integer of different size
            [-Wpointer-to-int-cast]

Cast the value through intptr_t first to quell compiler complaints
about how this gun appears to be aimed near our feet.  Then cast this
value to an int; this path assures the compiler we are smarter than we
look, or at least that we intend to aim the gun this way for a reason.
---
 builtin/fmt-merge-msg.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/builtin/fmt-merge-msg.c b/builtin/fmt-merge-msg.c
index 8ddefb3..fee65e0 100644
--- a/builtin/fmt-merge-msg.c
+++ b/builtin/fmt-merge-msg.c

@@ -182,7 +182,7 @@ static void add_branch_desc(struct strbuf *out,

const char *name)
        strbuf_release(&desc);
 }

-#define util_as_int(elem) ((int)((elem)->util))
+#define util_as_int(elem) ((int)(intptr_t)((elem)->util))

 static void record_person(int which, struct string_list *people,
                          struct commit *commit)
-- 
1.7.9.3