[PATCH] http-backend: drop strbuf pre-sizing from get_info_packs()

[Yusuke Hayashi via B4 Relay <devnull+yusuke8h.gmail.com@kernel.org>]

From: Yusuke Hayashi <yusuke8h@gmail.com>

get_info_packs() iterates over all packs in the repository to count
local packs, calls `strbuf_grow(&buf, cnt * 53 + 2)`, and then iterates
over the packs a second time to format each entry with `strbuf_addf()`.

This pre-sizing dates back to 2f4038ab33 (Git-aware CGI to provide dumb
HTTP transport, 2009-10-30) and is no longer worth keeping: `53` assumes
the length of a SHA-1 "P pack-<hex>.pack\n" line (under-counting the
77-byte lines in SHA-256 repositories), `cnt * 53 + 2` uses unchecked
arithmetic, and `strbuf_addf()` / `strbuf_addch()` already grow the
buffer automatically without needing an extra pass over the pack list.
Similar pre-sizing was recently removed in a9ce8526dc (pretty: drop
strbuf pre-sizing from add_rfc2047(), 2026-05-12).

Drop `cnt`, the counting loop, and the `strbuf_grow()` call.

Signed-off-by: Yusuke Hayashi <yusuke8h@gmail.com>
---
Inspired by https://lore.kernel.org/git/20260513185408.GA147423@coredump.intra.peff.net/
---
 http-backend.c | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/http-backend.c b/http-backend.c
index c7566b1d12..da9516a4c1 100644
--- a/http-backend.c
+++ b/http-backend.c
@@ -612,15 +612,8 @@ static void get_info_packs(struct strbuf *hdr, char *arg UNUSED)
 	size_t objdirlen = strlen(repo_get_object_directory(the_repository));
 	struct strbuf buf = STRBUF_INIT;
 	struct packed_git *p;
-	size_t cnt = 0;
 
 	select_getanyfile(hdr);
-	repo_for_each_pack(the_repository, p) {
-		if (p->pack_local)
-			cnt++;
-	}
-
-	strbuf_grow(&buf, cnt * 53 + 2);
 	repo_for_each_pack(the_repository, p) {
 		if (p->pack_local)
 			strbuf_addf(&buf, "P %s\n", p->pack_name + objdirlen + 6);

---
base-commit: 9354c5f04055932909b660a237905b360cba195a
change-id: 20261113-http-backend-drop-strbuf-presizing-6f496552d0ca