test-hashmap: use xsnprintf rather than snprintf

peff · gitster · commit cbadf0ee37de · 2018-02-14T10:31:09.000-08:00
In general, using a bare snprintf can truncate the resulting
buffer, leading to confusing results. In this case we know
that our buffer is sized large enough to accommodate our
loop, so there's no bug. However, we should use xsnprintf()
to document (and check) that assumption, and to model good
practice to people reading the code.

Signed-off-by: Jeff King &lt;peff@peff.net&gt;
Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
diff --git a/t/helper/test-hashmap.c b/t/helper/test-hashmap.c
@@ -87,7 +87,7 @@ static void perf_hashmap(unsigned int method, unsigned int rounds)
 	ALLOC_ARRAY(entries, TEST_SIZE);
 	ALLOC_ARRAY(hashes, TEST_SIZE);
 	for (i = 0; i < TEST_SIZE; i++) {
-		snprintf(buf, sizeof(buf), "%i", i);
+		xsnprintf(buf, sizeof(buf), "%i", i);
 		entries[i] = alloc_test_entry(0, buf, strlen(buf), "", 0);
 		hashes[i] = hash(method, i, entries[i]->key);
 	}

Original file line number	Diff line number	Diff line change
`@@ -87,7 +87,7 @@ static void perf_hashmap(unsigned int method, unsigned int rounds)`
`87`	`87`	`ALLOC_ARRAY(entries, TEST_SIZE);`
`88`	`88`	`ALLOC_ARRAY(hashes, TEST_SIZE);`
`89`	`89`	`for (i = 0; i < TEST_SIZE; i++) {`
`90`		`- snprintf(buf, sizeof(buf), "%i", i);`
	`90`	`+ xsnprintf(buf, sizeof(buf), "%i", i);`
`91`	`91`	`entries[i] = alloc_test_entry(0, buf, strlen(buf), "", 0);`
`92`	`92`	`hashes[i] = hash(method, i, entries[i]->key);`
`93`	`93`	`}`