prepare_repo_settings(): plug leak of config values

We call repo_config_get_string() for fetch.negotiationAlgorithm, which
allocates a copy of the string, but we never free it.

We could add a call to free(), but there's an even simpler solution: we
don't need the string to persist beyond a few strcasecmp() calls, so we
can instead use the "_tmp" variant which gives us a const pointer to the
cached value.

We need to switch the type of "strval" to "const char *" for this to
work, which affects a similar call that checks core.untrackedCache. But
it's in the same boat! It doesn't actually need the value to persist
beyond a maybe_bool() check (though it does remember to correctly free
the string afterwards). So we can simplify it at the same time.

Note that this core.untrackedCache check arguably should be using
repo_config_get_maybe_bool(), but there are some subtle behavior
changes. E.g., it doesn't currently allow a value-less "true". Arguably
it should, but let's avoid lumping further changes in what should be a
simple leak cleanup.

Signed-off-by: Jeff King <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: peff

repo-settings.c

@@ -15,7 +15,7 @@ void prepare_repo_settings(struct repository *r)
 {
 	int experimental;
 	int value;
-	char *strval;
+	const char *strval;
 	int manyfiles;
 
 	if (!r->gitdir)
@@ -67,7 +67,7 @@ void prepare_repo_settings(struct repository *r)
 	if (!repo_config_get_int(r, "index.version", &value))
 		r->settings.index_version = value;
 
-	if (!repo_config_get_string(r, "core.untrackedcache", &strval)) {
+	if (!repo_config_get_string_tmp(r, "core.untrackedcache", &strval)) {
 		int v = git_parse_maybe_bool(strval);
 
 		/*
@@ -78,10 +78,9 @@ void prepare_repo_settings(struct repository *r)
 		if (v >= 0)
 			r->settings.core_untracked_cache = v ?
 				UNTRACKED_CACHE_WRITE : UNTRACKED_CACHE_REMOVE;
-		free(strval);
 	}
 
-	if (!repo_config_get_string(r, "fetch.negotiationalgorithm", &strval)) {
+	if (!repo_config_get_string_tmp(r, "fetch.negotiationalgorithm", &strval)) {
 		int fetch_default = r->settings.fetch_negotiation_algorithm;
 		if (!strcasecmp(strval, "skipping"))
 			r->settings.fetch_negotiation_algorithm = FETCH_NEGOTIATION_SKIPPING;