[PATCH v4] merge-recursive: check GIT_MERGE_VERBOSITY only once

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

Get 'GIT_MERGE_VERBOSITY' environment variable only once in
init_merge_options() and store the pointer to its value for the further check.
No intervening calls to getenv(), putenv(), setenv() or unsetenv() are done
between the initial getenv() call and the consequential result pass to strtol()
as these environment related functions could modify the string pointer returned
by the initial getenv() call.

Signed-off-by: Andrey Okoshkin <a.okoshkin@samsung.com>
Reviewed-by: Stefan Beller <sbeller@google.com>
---
Added 'reviewed-by' field.
 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