Subject: Re: [PATCH] git-compat-util: Avoid strcasecmp() being inlined

From: Junio C Hamano <[email-masked]>
Date: Thu, 12 Sep 2013 11:35:21 -0700

Jeff King <[email-masked]> writes:

> On Thu, Sep 12, 2013 at 08:37:08AM -0700, Junio C Hamano wrote:
>
>> > I wonder if GCC has changed it's behaviour to more closely match C99.
>> > Clang as a compatibility article about this sort of issue:
>> >
>> >     http://clang.llvm.org/compatibility.html#inline
>> 
>> Interesting.  The ways the page suggests as fixes are
>> 
>>  - change it to a "statis inline";
>>  - remove "inline" from the definition;
>>  - provide an external (non-inline) def somewhere else;
>>  - compile with gnu899 dialect.
>
> Right, option 3 seems perfectly reasonable to me, as we must be prepared
> to cope with a decision not to inline the function, and there has to be
> _some_ linked implementation. But shouldn't libc be providing an
> external, linkable strcasecmp in this case?

That is exactly my point when I said that the third one is nonsense
for a definition in the standard header file.

I think we would want something like below.

-- >8 --
Subject: [PATCH] mailmap: work around implementations with pure inline strcasecmp

On some systems, string.h has _only_ inline definition of strcasecmp
without supplying a non-inline implementation anywhere, which is,
eh, "unusual"; we cannot take an address of such a function to store
it in namemap.cmp.  Work it around by introducing our own level of
indirection.

Signed-off-by: Junio C Hamano <[email-masked]>
---
 mailmap.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/mailmap.c b/mailmap.c
index 44614fc..8863e23 100644
--- a/mailmap.c
+++ b/mailmap.c
@@ -52,6 +52,19 @@ static void free_mailmap_entry(void *p, const char *s)
 	string_list_clear_func(&me->namemap, free_mailmap_info);
 }
 
+/*
+ * On some systems, string.h has _only_ inline definition of strcasecmp
+ * without supplying a non-inline implementation anywhere, which is, eh,
+ * "unusual"; we cannot take an address of such a function to store it in
+ * namemap.cmp.  This is here as a workaround---do not assign strcasecmp
+ * directly to namemap.cmp until we know no systems that matter have such
+ * an "unusual" string.h.
+ */
+static int namemap_cmp(const char *a, const char *b)
+{
+	return strcasecmp(a, b);
+}
+
 static void add_mapping(struct string_list *map,
 			char *new_name, char *new_email,
 			char *old_name, char *old_email)
@@ -75,7 +88,7 @@ static void add_mapping(struct string_list *map,
 		item = string_list_insert_at_index(map, index, old_email);
 		me = xcalloc(1, sizeof(struct mailmap_entry));
 		me->namemap.strdup_strings = 1;
-		me->namemap.cmp = strcasecmp;
+		me->namemap.cmp = namemap_cmp;
 		item->util = me;
 	}
 
@@ -241,7 +254,7 @@ int read_mailmap(struct string_list *map, char **repo_abbrev)
 	int err = 0;
 
 	map->strdup_strings = 1;
-	map->cmp = strcasecmp;
+	map->cmp = namemap_cmp;
 
 	if (!git_mailmap_blob && is_bare_repository())
 		git_mailmap_blob = "HEAD:.mailmap";
-- 
1.8.4-485-gec42fe2