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Re: [PATCH] ci(win+Meson): build in Release mode, avoiding t7001-mv hangs

From
Junio C Hamano <gitster@pobox.com>
Date
Apr 29, 2025, 20:48 UTC
Message-ID
<xmqqplgu4ru5.fsf@gitster.g>
In-Reply-To
<aBDD-NeN2YoQbU9S@pks.im>
Patrick Steinhardt <ps@pks.im> writes:
Show 24 quoted lines
> @@ -213,6 +228,8 @@ int cmd_mv(int argc,
>  	struct cache_entry *ce;
>  	struct string_list only_match_skip_worktree = STRING_LIST_INIT_DUP;
>  	struct string_list dirty_paths = STRING_LIST_INIT_DUP;
> +	struct hashmap moved_dirs = HASHMAP_INIT(pathmap_cmp, NULL);
> +	struct strbuf pathbuf = STRBUF_INIT;
>  	int ret;
>  
>  	git_config(git_default_config, NULL);
> @@ -331,11 +348,17 @@ int cmd_mv(int argc,
>  
>  dir_check:
>  		if (S_ISDIR(st.st_mode)) {
> +			struct pathmap_entry *entry;
>  			char *dst_with_slash;
>  			size_t dst_with_slash_len;
>  			int j, n;
>  			int first = index_name_pos(the_repository->index, src, length), last;
>  
> +			entry = xmalloc(sizeof(*entry));
> +			entry->path = src;
> +			hashmap_entry_init(&entry->ent, fspathhash(src));
> +			hashmap_add(&moved_dirs, &entry->ent);
> +

OK, this collects in moved_dirs the directories that will get moved. And then a separate loop, ...

> +	for (i = 0; i < argc; i++) {
> +		const char *slash_pos;
> +
> +		strbuf_addstr(&pathbuf, sources.v[i]);

Shouldn't there be a call to strbuf_reset(&pathbuf) before doing this?

> +		slash_pos = strrchr(pathbuf.buf, '/');

And start from the deepest directory, going one level up per iteration, ...

Show 7 quoted lines
> +		while (slash_pos > pathbuf.buf) {
> +			struct pathmap_entry needle;
> +
> +			strbuf_setlen(&pathbuf, slash_pos - pathbuf.buf);
> +
> +			needle.path = pathbuf.buf;
> +			hashmap_entry_init(&needle.ent, fspathhash(pathbuf.buf));
... see if the path being moved falls within that subdirectory.
> +			if (!hashmap_get_entry(&moved_dirs, &needle, ent, NULL))
> +				continue;
If there is no overlap, we need to do anything special.
> +			if (!ignore_errors)
> +				die(_("cannot move both parent directory '%s' and its child '%s'"),
> +				    pathbuf.buf, sources.v[i]);
Otherwise we are in trouble.
Show 10 quoted lines
> +			if (--argc > 0) {
> +				int n = argc - i;
> +				strvec_remove(&sources, i);
> +				strvec_remove(&destinations, i);
> +				MOVE_ARRAY(modes + i, modes + i + 1, n);
> +				MOVE_ARRAY(submodule_gitfiles + i,
> +					   submodule_gitfiles + i + 1, n);
> +				i--;
> +				break;
> +			}
So with
	$ git mv a/ a/b x y z/

then a/ is left in the argv[]/sources[]/destinations[] arrays, and upon inspecting a/b, we come here and in order to ignore a/b, we shift it out; the resulting arrays would have a/, x, and y being moved to z/.

It somehow feels troubling that it would lead to a different result if I give a morally equivalent arguments, i.e.

	$ git mv a/b a/ x y z/
where a/b survives and a/ gets omitted.

One thing that came to my mind (without concrete "here is the right way to solve it" that I am myself convinced) is this.

 * Should this code path even have its own ignore-errors handling?
   "git mv a b z/", when 'a' does not exist, may ignore 'a' and move
   only 'b', which may make sense.  But the original command line in
   that case is a plausibly correct one if there weren't missing or
   unmovable paths.  The command line "git mv a/ a/b z/" seems to
   fall into a different category (aka "total nonsense"); no matter
   how you fix the items in your working tree files, you cannot make
   it plausibly correct.

a totally unrelated tangent that made me scratch my head while reading the original ocde is the dest_paths variable. It is never used as a collection to hold potentially multiple paths; it is a strvec only to be able to call internel_prefix_pathspec() with, and used only once with only one element in the vector. At least it should lose the plural 's' suffix to unconfuse its readers, I would think.

Previous: Patrick SteinhardtNext: Patrick Steinhardt
Message 6 of 17 in “ci(win+Meson): build in Release mode, avoiding t7001-mv hangs”
  1. ci(win+Meson): build in Release mode, avoiding t7001-mv hangsJohannes Schindelin via GitGitGadget, Apr 25, 2025
  2. Junio C HamanoApr 25, 2025
  3. Patrick SteinhardtApr 28, 2025
  4. Junio C HamanoApr 28, 2025
  5. Patrick SteinhardtApr 29, 2025
  6. Junio C HamanoApr 29, 2025
  7. Patrick SteinhardtApr 30, 2025
  8. Patrick SteinhardtApr 30, 2025
  9. Kristoffer HaugsbakkApr 29, 2025
  10. ci(win+Meson): build in Release modeJohannes Schindelin via GitGitGadget, May 3, 2025
  11. Patrick SteinhardtMay 5, 2025
  12. Johannes SchindelinMay 5, 2025
  13. Patrick SteinhardtMay 5, 2025
  14. Junio C HamanoMay 5, 2025
  15. Patrick SteinhardtMay 6, 2025
  16. Johannes SchindelinMay 6, 2025
  17. Junio C HamanoMay 8, 2025

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