Re: [PATCH] submodule-config: use explicit empty string instead of strbuf in config_from()

[Heiko Voigt <hvoigt@hvoigt.net>]

Hi,

On Tue, Jul 19, 2016 at 09:05:43PM +0200, René Scharfe wrote:
> Use a string constant instead of an empty strbuf to shorten the code
> and make it easier to read.

This must have been some oversight from my original code. I also can not
see any purpose.

> Signed-off-by: Rene Scharfe <l.s.r@web.de>
> ---
> ... unless someone can come up with a suitable non-empty string to feed
> to git_config_from_mem() as its name parameter.

If we would want to be absolutely correct we could use something like
"SHA1:.gitmodules". E.g. like we use to lookup the blob in
gitmodule_sha1_from_commit():

	strbuf_addf(&rev, "%s:.gitmodules", sha1_to_hex(commit_sha1));

And now I see where this was leftover from... before extracting this
function this code was filling the strbuf.

How about this instead?

---8<------
Subject: [PATCH] fix passing a name for config from submodules

In commit 959b5455 we implemented the initial version of the submodule
config cache. During development of that initial version we extracted
the function gitmodule_sha1_from_commit(). During that process we missed
that the strbuf rev was still used in config_from() and now is left
empty. Lets fix this by also returning this string.

Signed-off-by: Heiko Voigt <hvoigt@hvoigt.net>
---

Its not exactly pretty with all the releases before the returns but
this is what I could quickly come up with...

 submodule-config.c | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/submodule-config.c b/submodule-config.c
index 077db40..dccea59 100644
--- a/submodule-config.c
+++ b/submodule-config.c
@@ -371,9 +371,9 @@ static int parse_config(const char *var, const char *value, void *data)
 }
 
 static int gitmodule_sha1_from_commit(const unsigned char *commit_sha1,
-				      unsigned char *gitmodules_sha1)
+				      unsigned char *gitmodules_sha1,
+				      struct strbuf *rev)
 {
-	struct strbuf rev = STRBUF_INIT;
 	int ret = 0;
 
 	if (is_null_sha1(commit_sha1)) {
@@ -381,11 +381,10 @@ static int gitmodule_sha1_from_commit(const unsigned char *commit_sha1,
 		return 1;
 	}
 
-	strbuf_addf(&rev, "%s:.gitmodules", sha1_to_hex(commit_sha1));
-	if (get_sha1(rev.buf, gitmodules_sha1) >= 0)
+	strbuf_addf(rev, "%s:.gitmodules", sha1_to_hex(commit_sha1));
+	if (get_sha1(rev->buf, gitmodules_sha1) >= 0)
 		ret = 1;
 
-	strbuf_release(&rev);
 	return ret;
 }
 
@@ -420,8 +419,10 @@ static const struct submodule *config_from(struct submodule_cache *cache,
 		return entry->config;
 	}
 
-	if (!gitmodule_sha1_from_commit(commit_sha1, sha1))
+	if (!gitmodule_sha1_from_commit(commit_sha1, sha1, &rev)) {
+		strbuf_release(&rev);
 		return NULL;
+	}
 
 	switch (lookup_type) {
 	case lookup_name:
@@ -431,14 +432,19 @@ static const struct submodule *config_from(struct submodule_cache *cache,
 		submodule = cache_lookup_path(cache, sha1, key);
 		break;
 	}
-	if (submodule)
+	if (submodule) {
+		strbuf_release(&rev);
 		return submodule;
+	}
 
 	config = read_sha1_file(sha1, &type, &config_size);
-	if (!config)
+	if (!config) {
+		strbuf_release(&rev);
 		return NULL;
+	}
 
 	if (type != OBJ_BLOB) {
+		strbuf_release(&rev);
 		free(config);
 		return NULL;
 	}
@@ -450,6 +456,7 @@ static const struct submodule *config_from(struct submodule_cache *cache,
 	parameter.overwrite = 0;
 	git_config_from_mem(parse_config, "submodule-blob", rev.buf,
 			config, config_size, &parameter);
+	strbuf_release(&rev);
 	free(config);
 
 	switch (lookup_type) {
-- 
2.4.2.387.gf86f31a