[PATCH v2] merge-recursive: check GIT_MERGE_VERBOSITY only once

[Andrey Okoshkin <a.okoshkin@samsung.com>]

Check 'GIT_MERGE_VERBOSITY' environment variable only once in
init_merge_options().
Consequential call of getenv() may return NULL pointer.
However the stored pointer to the obtained getenv() result may be invalidated
by some other getenv() call as getenv() is not thread-safe.

Signed-off-by: Andrey Okoshkin <a.okoshkin@samsung.com>
Reviewed-by: Stefan Beller <sbeller@google.com>
---
Changes since the previous patch:
* no actions are taken between the merge_verbosity assignment and check.
 merge-recursive.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/merge-recursive.c b/merge-recursive.c
index 1494ffdb8..60084e3a0 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -2163,6 +2163,7 @@ static void merge_recursive_config(struct merge_options *o)
 
 void init_merge_options(struct merge_options *o)
 {
+	const char *merge_verbosity;
 	memset(o, 0, sizeof(struct merge_options));
 	o->verbosity = 2;
 	o->buffer_output = 1;
@@ -2171,9 +2172,9 @@ void init_merge_options(struct merge_options *o)
 	o->renormalize = 0;
 	o->detect_rename = 1;
 	merge_recursive_config(o);
-	if (getenv("GIT_MERGE_VERBOSITY"))
-		o->verbosity =
-			strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
+	merge_verbosity = getenv("GIT_MERGE_VERBOSITY");
+	if (merge_verbosity)
+		o->verbosity = strtol(merge_verbosity, NULL, 10);
 	if (o->verbosity >= 5)
 		o->buffer_output = 0;
 	strbuf_init(&o->obuf, 0);
-- 
2.14.3