Re: [PATCH] hex: add and use strbuf_add_oid_hex()

[Jeff King <peff@peff.net>]

On Wed, May 13, 2026 at 05:49:11PM +0200, René Scharfe wrote:

> Add a function for adding the full hexadecimal hash value of an object
> ID to a strbuf.  It's thread-safe and slightly more efficient than using
> strbuf_addstr() with oid_to_hex() because it doesn't have to determine
> the length of the string or copy it from the intermediate static buffer.
> 
> Add and apply a semantic patch to use it throughout the code base.
> 
> I get a tiny speedup for git log showing a single hash per commit:
> 
> Benchmark 1: ./git_main log --format=%H
>   Time (mean ± σ):      91.2 ms ±   0.7 ms    [User: 51.9 ms, System: 38.6 ms]
>   Range (min … max):    89.8 ms …  92.6 ms    31 runs
> 
> Benchmark 2: ./git log --format=%H
>   Time (mean ± σ):      90.5 ms ±   0.7 ms    [User: 51.0 ms, System: 38.8 ms]
>   Range (min … max):    89.2 ms …  92.3 ms    32 runs

Probably the most extreme benchmark would be:

  git cat-file --batch-all-objects --batch-check='%(objectname)'

which is really just dumping the oids from packfiles. I got ~3% speedup,
though like yours it's within the run-to-run noise.

I think this is worth doing solely for removing more instances of global
buffers, though.

-Peff