Re: [PATCH v3 3/3] core: convert build-time USE_NSEC into runtime core.useNanosec

On Wed, Aug 19, 2026 at 09:09:59AM -0400, D. Ben Knoble wrote:

On Wed, Aug 19, 2026 at 4:24 AM Patrick Steinhardt [off-list ref] wrote:

quoted

On Tue, Aug 18, 2026 at 10:59:47AM -0400, D. Ben Knoble wrote:

quoted

diff --git a/read-cache.c b/read-cache.c
index 6c449f393d..31888f77ee 100644
--- a/read-cache.c
+++ b/read-cache.c

@@ -353,12 +353,18 @@ static int ce_match_stat_basic(const struct cache_entry *ce, struct stat *st)
 static int is_racy_stat(const struct index_state *istate,
                      const struct stat_data *sd)
 {
+#ifndef NO_NSEC
+     int use_nsec = repo_config_values(istate->repo)->use_nanosec;
+#endif
+
      return (istate->timestamp.sec &&
-#ifdef USE_NSEC
-              /* nanosecond timestamped files can also be racy! */
-             (istate->timestamp.sec < sd->sd_mtime.sec ||
-              (istate->timestamp.sec == sd->sd_mtime.sec &&
-               istate->timestamp.nsec <= sd->sd_mtime.nsec))
+#ifndef NO_NSEC
+             /* nanosecond timestamped files can also be racy! */
+             use_nsec
+             ? (istate->timestamp.sec < sd->sd_mtime.sec ||
+                (istate->timestamp.sec == sd->sd_mtime.sec &&
+                 istate->timestamp.nsec <= sd->sd_mtime.nsec))
+             : istate->timestamp.sec <= sd->sd_mtime.sec
 #else
              istate->timestamp.sec <= sd->sd_mtime.sec
 #endif

I think this would be a bit more readable if we had a single NO_NSEC
block.

I'm not sure what "single block" means here, but I think the plan (see
reply to Junio) is to make this more readable by not needing
pre-processor directives at all.

That'd be quite welcome indeed. The less ifdeffery the bettery. :)

quoted

There's one more site in "builtin/update-index.c" where we mention
USE_NSEC that wasn't updated as part of this patch.

Oh, did I miss one? The only spot I saw in builtin/update-index.c that
mentions USE_NSEC is a comment that I'm sure patch 3 updated. Maybe
you were thinking of that, or maybe you know of something I left out?
(That is, locally on this branch, "git grep USE_NSEC" returns one hit
in Documentation/RelNotes/2.5.0.adoc.)

Oh, I guess I just missed it because I already trimmed context of this
mail. Never mind then.

Patrick