Re: [PATCH v3] Teach git apply to respect core.fileMode settings

[Johannes Schindelin <Johannes.Schindelin@gmx.de>]

Hi,

On Wed, 20 Dec 2023, Chandra Pratap via GitGitGadget wrote:

> diff --git a/apply.c b/apply.c
> index 3d69fec836d..58f26c40413 100644
> --- a/apply.c
> +++ b/apply.c
> @@ -3778,8 +3778,12 @@ static int check_preimage(struct apply_state *state,
>  		return error_errno("%s", old_name);
>  	}
>
> -	if (!state->cached && !previous)
> -		st_mode = ce_mode_from_stat(*ce, st->st_mode);
> +	if (!state->cached && !previous) {
> +		if (!trust_executable_bit)
> +			st_mode = *ce ? (*ce)->ce_mode : patch->old_mode;
> +		else
> +			st_mode = ce_mode_from_stat(*ce, st->st_mode);
> +	}

I noticed a CI breakage in t2106.3 in `seen` that seems to be caused by
this, and I can make it go away with this patch:

-- snip --
From 5c2a709b629d396528dabe2f92bf3d4deb5bbdb2 Mon Sep 17 00:00:00 2001
From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Sun, 24 Dec 2023 14:01:49 +0100
Subject: [PATCH] fixup! Teach git apply to respect core.fileMode settings

As pointed out e.g. by t2016.3(git checkout -p), if the patch is to be
applied in reverse (`git apply -R`), then the `old_mode` is actually 0,
and we must use `new_mode` instead.

While at it, add some defensive code to ignore `ce_mode` should it be 0.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 apply.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/apply.c b/apply.c
index 58f26c404136..5ad06ef2f843 100644
--- a/apply.c
+++ b/apply.c
@@ -3780,7 +3780,9 @@ static int check_preimage(struct apply_state *state,

 	if (!state->cached && !previous) {
 		if (!trust_executable_bit)
-			st_mode = *ce ? (*ce)->ce_mode : patch->old_mode;
+			st_mode = *ce && (*ce)->ce_mode ? (*ce)->ce_mode :
+				(state->apply_in_reverse ?
+				 patch->new_mode : patch->old_mode);
 		else
 			st_mode = ce_mode_from_stat(*ce, st->st_mode);
 	}
-- snap --

I guess you can slap on that `Reviewed-by:` footer again, after all... ;-)

Ciao,
Johannes