[1/1] add: Enable attr pathspec magic for git-add.

Commit Message

Joanna Wang Oct. 7, 2023, 12:28 a.m. UTC

This lets users limit added files or exclude files based on file
attributes. For example, the chromium project would like to use
this like "git add --all ':(exclude,attr:submodule)'", as submodules
are managed in a unique way and often results in submodule changes
that users do not want in their commits.

This does not change any attr magic implementation. It is only adding
attr as an allowed pathspec in git-add, which was previously
blocked by GUARD_PATHSPEC and a pathspec mask in parse_pathspec()).

With this patch, attr is supported. It is possible that when the attr
pathspec feature was first added in
b0db704652 (pathspec: allow querying for attributes, 2017-03-13), 
"PATHSPEC_ATTR" was just unintentionally left out of a few
GUARD_PATHSPEC() invocations. Later, to get a more user-friendly error
message when attr was used with git-add, PATHSPEC_ATTR was added as a
mask to git-add's invocation of parse_pathspec()
84d938b732 (add: do not accept pathspec magic 'attr', 2018-09-18).

git-stash which goes through the same GUARD_PATHSPEC(), currently
does not work with attr. So a PATHSPEC_ATTR mask has been added
to its parse_pathspec and parse_pathspec_file()

Signed-off-by: Joanna Wang <[e-mail]>
---

> (perhaps except for the commit title on the Subject: header).
Added 'add:' and specified it is 'patchpsec' magic, but lmk if i'm still missing something.

> This is rather a poor statement to make, as it hints that there are
> known breakages this change will reveal that you are not telling us,
>although I suspect that it is not the case.
Yes, sorry I did not mean to make this hint. I was trying to express that
if bugs did come up, we would not abandon this effort and expect someone
else to fix it. I have removed this line. I realized I also don't want
to say we will forever be on the hook for fixing every related bug that comes up.

> These are good things to add to the new test this patch adds.
Tests added.

>Hmph, is it a good idea in general to use ALL_MAGIC in guard?
My original reasoning was using ALL_MAGIC would prevent new magic pathspecs
from being unintentionally left out of commands and if a new magic does not
work with a command, whoever adds it should change ALL_MAGIC back to listing
them individually in the same patch. But yes, listing them individually seems
safer. Better to accidentally leave magic out that can be added with intention
later rather than make it easy to accidentally leave unsupported magic in.
I switched it back to listing individually.

>It is strongly preferrable, instead of butchering this test that
>guards these two mechanisms from being broken, to find a command
>that still has some restriction on the magic it allows, and use it
>to make sure they still trigger and give "magic not supported" error
>message.
I added the test back with git-stash, which, after more testing i discovered it
actually did not fully work with attr. More info below.

>Unless it matters that these files have recent timestamps, do not
>use "touch", merely to ensure presence of a file.  We often use a
>simple redirection.
Done

>A tangent (to the topic of testing, but relevant to the whole
>patch).  I notice 'stash' is mentioned on the topic, but I do not
>see changes to the codepath that is specific to 'stash', and changes
>to the tests do not demonstrate existing breakage.  The lack of code
>changes probably is because something shared, which is pretected
>with magic guard lifted by the patch, is called from 'stash' as well
>as 'add', or something?
Yes, the previous patch enabled attr with git-stash which was only blocked
at the shared dir.c GUARD_PATHSPEC level. I thought attr was working for git-stash
but I was wrong after a few more manual tests.
So I added PATHSPEC_ATTR as a mask to stash's parse_pathspec and parse_pathspec_file.

 builtin/add.c                  |   7 ++-
 builtin/stash.c                |   4 +-
 dir.c                          |  13 ++--
 t/t6135-pathspec-with-attrs.sh | 109 +++++++++++++++++++++++++++++++--
 4 files changed, 117 insertions(+), 16 deletions(-)

Comments

Joanna Wang Oct. 7, 2023, 12:50 a.m. UTC | #1

>+test_expect_success 'check that attr magic works for git' '
>+'
Sorry, i forgot to take this out. I can fix it in the next pathset after
the next round of review.

Junio C Hamano Oct. 7, 2023, 10:10 a.m. UTC | #2

Joanna Wang <[e-mail]> writes:

> Added 'add:' and specified it is 'patchpsec' magic, but lmk if i'm still missing something.

If you run

    $ git shortlog --no-merges v2.42.0..

or something on your branch to see how well its subject blends with
others, you'd start wanting to (1) downcase "Enable", and (2) omit
the full-stop after the title, to make it look similar to others.

> diff --git a/builtin/stash.c b/builtin/stash.c
> index 1ad496985a..9c77d3e4e4 100644
> --- a/builtin/stash.c
> +++ b/builtin/stash.c
> @@ -1760,7 +1760,7 @@ static int push_stash(int argc, const char **argv, const char *prefix,
>  		}
>  	}
>  
> -	parse_pathspec(&ps, 0, PATHSPEC_PREFER_FULL | PATHSPEC_PREFIX_ORIGIN,
> +	parse_pathspec(&ps, PATHSPEC_ATTR, PATHSPEC_PREFER_FULL | PATHSPEC_PREFIX_ORIGIN,
>  		       prefix, argv);

This becomes necessary because "stash" later goes through other
places this patch touches (e.g., dir.c::exclude_matches_pathspec()?)
that happened to be serving as a guard for another code "stash" has
that is not prepared to handle attribute magic?  Do you know what
exactly is not ready, so that perhaps others can help figuring out
how to make it ready for the attr magic?

> diff --git a/dir.c b/dir.c
> index 8486e4d56f..9bf9b53ca5 100644
> --- a/dir.c
> +++ b/dir.c
> @@ -2174,12 +2174,13 @@ static int exclude_matches_pathspec(const char *path, int pathlen,
>  		return 0;
>  
>  	GUARD_PATHSPEC(pathspec,
> -		       PATHSPEC_FROMTOP |
> -		       PATHSPEC_MAXDEPTH |
> -		       PATHSPEC_LITERAL |
> -		       PATHSPEC_GLOB |
> -		       PATHSPEC_ICASE |
> -		       PATHSPEC_EXCLUDE);
> +                       PATHSPEC_FROMTOP |
> +                       PATHSPEC_MAXDEPTH |
> +                       PATHSPEC_LITERAL |
> +                       PATHSPEC_GLOB |
> +                       PATHSPEC_ICASE |
> +                       PATHSPEC_EXCLUDE |
> +                       PATHSPEC_ATTR);

Why this reindent?

> @@ -239,16 +254,100 @@ test_expect_success 'fail on multiple attr specifie
>  	test_i18ngrep "Only one" actual
>  '
>  
> -test_expect_success 'fail if attr magic is used places not implemented' '
> +test_expect_success 'fail if attr magic is used in places not implemented' '
>  	# The main purpose of this test is to check that we actually fail
>  	# when you attempt to use attr magic in commands that do not implement
> -	# attr magic. This test does not advocate git-add to stay that way,
> -	# though, but git-add is convenient as it has its own internal pathspec
> -	# parsing.
> -	test_must_fail git add ":(attr:labelB)" 2>actual &&
> +	# attr magic. This test does not advocate stash push to stay that way.
> +	# When you teach the command to grok the pathspec, you need to find
> +	# another commnad to replace it for the test.

There is a typo here.  Please do not expect your reviewers to always
offer a perfect solution to your problem and blindly copy what they
fed you.  Instead, just like other project participants try to find
bugs and improvement opportunities in your patch, please lend them
sanity-checking eyeballs in return ;-)

Patch

diff --git a/builtin/add.c b/builtin/add.c
index c27254a5cd..2de83964a3 100644
--- a/builtin/add.c
+++ b/builtin/add.c
@@ -424,7 +424,7 @@  int cmd_add(int argc, const char **argv, const char *prefix)
 	 * Check the "pathspec '%s' did not match any files" block
 	 * below before enabling new magic.
 	 */
-	parse_pathspec(&pathspec, PATHSPEC_ATTR,
+	parse_pathspec(&pathspec, 0,
 		       PATHSPEC_PREFER_FULL |
 		       PATHSPEC_SYMLINK_LEADING_PATH,
 		       prefix, argv);
@@ -433,7 +433,7 @@  int cmd_add(int argc, const char **argv, const char *prefix)
 		if (pathspec.nr)
 			die(_("'%s' and pathspec arguments cannot be used together"), "--pathspec-from-file");
 
-		parse_pathspec_file(&pathspec, PATHSPEC_ATTR,
+		parse_pathspec_file(&pathspec, 0,
 				    PATHSPEC_PREFER_FULL |
 				    PATHSPEC_SYMLINK_LEADING_PATH,
 				    prefix, pathspec_from_file, pathspec_file_nul);
@@ -504,7 +504,8 @@  int cmd_add(int argc, const char **argv, const char *prefix)
 			       PATHSPEC_LITERAL |
 			       PATHSPEC_GLOB |
 			       PATHSPEC_ICASE |
-			       PATHSPEC_EXCLUDE);
+			       PATHSPEC_EXCLUDE |
+			       PATHSPEC_ATTR);
 
 		for (i = 0; i < pathspec.nr; i++) {
 			const char *path = pathspec.items[i].match;
diff --git a/builtin/stash.c b/builtin/stash.c
index 1ad496985a..9c77d3e4e4 100644
--- a/builtin/stash.c
+++ b/builtin/stash.c
@@ -1760,7 +1760,7 @@  static int push_stash(int argc, const char **argv, const char *prefix,
 		}
 	}
 
-	parse_pathspec(&ps, 0, PATHSPEC_PREFER_FULL | PATHSPEC_PREFIX_ORIGIN,
+	parse_pathspec(&ps, PATHSPEC_ATTR, PATHSPEC_PREFER_FULL | PATHSPEC_PREFIX_ORIGIN,
 		       prefix, argv);
 
 	if (pathspec_from_file) {
@@ -1773,7 +1773,7 @@  static int push_stash(int argc, const char **argv, const char *prefix,
 		if (ps.nr)
 			die(_("'%s' and pathspec arguments cannot be used together"), "--pathspec-from-file");
 
-		parse_pathspec_file(&ps, 0,
+		parse_pathspec_file(&ps, PATHSPEC_ATTR,
 				    PATHSPEC_PREFER_FULL | PATHSPEC_PREFIX_ORIGIN,
 				    prefix, pathspec_from_file, pathspec_file_nul);
 	} else if (pathspec_file_nul) {
diff --git a/dir.c b/dir.c
index 8486e4d56f..9bf9b53ca5 100644
--- a/dir.c
+++ b/dir.c
@@ -2174,12 +2174,13 @@  static int exclude_matches_pathspec(const char *path, int pathlen,
 		return 0;
 
 	GUARD_PATHSPEC(pathspec,
-		       PATHSPEC_FROMTOP |
-		       PATHSPEC_MAXDEPTH |
-		       PATHSPEC_LITERAL |
-		       PATHSPEC_GLOB |
-		       PATHSPEC_ICASE |
-		       PATHSPEC_EXCLUDE);
+                       PATHSPEC_FROMTOP |
+                       PATHSPEC_MAXDEPTH |
+                       PATHSPEC_LITERAL |
+                       PATHSPEC_GLOB |
+                       PATHSPEC_ICASE |
+                       PATHSPEC_EXCLUDE |
+                       PATHSPEC_ATTR);
 
 	for (i = 0; i < pathspec->nr; i++) {
 		const struct pathspec_item *item = &pathspec->items[i];
diff --git a/t/t6135-pathspec-with-attrs.sh b/t/t6135-pathspec-with-attrs.sh
index f70c395e75..531b4f4d5e 100755
--- a/t/t6135-pathspec-with-attrs.sh
+++ b/t/t6135-pathspec-with-attrs.sh
@@ -64,12 +64,24 @@  test_expect_success 'setup .gitattributes' '
 	fileSetLabel label
 	fileValue label=foo
 	fileWrongLabel label☺
+	newFileA* labelA
+	newFileB* labelB
 	EOF
 	echo fileSetLabel label1 >sub/.gitattributes &&
 	git add .gitattributes sub/.gitattributes &&
 	git commit -m "add attributes"
 '
 
+test_expect_success 'setup .gitignore' '
+	cat <<-\EOF >.gitignore &&
+	actual
+	expect
+	pathspec_file
+	EOF
+	git add .gitignore &&
+	git commit -m "add gitignore"
+'
+
 test_expect_success 'check specific set attr' '
 	cat <<-\EOF >expect &&
 	fileSetLabel
@@ -150,6 +162,7 @@  test_expect_success 'check specific value attr (2)' '
 test_expect_success 'check unspecified attr' '
 	cat <<-\EOF >expect &&
 	.gitattributes
+	.gitignore
 	fileA
 	fileAB
 	fileAC
@@ -175,6 +188,7 @@  test_expect_success 'check unspecified attr' '
 test_expect_success 'check unspecified attr (2)' '
 	cat <<-\EOF >expect &&
 	HEAD:.gitattributes
+	HEAD:.gitignore
 	HEAD:fileA
 	HEAD:fileAB
 	HEAD:fileAC
@@ -200,6 +214,7 @@  test_expect_success 'check unspecified attr (2)' '
 test_expect_success 'check multiple unspecified attr' '
 	cat <<-\EOF >expect &&
 	.gitattributes
+	.gitignore
 	fileC
 	fileNoLabel
 	fileWrongLabel
@@ -239,16 +254,100 @@  test_expect_success 'fail on multiple attr specifiers in one pathspec item' '
 	test_i18ngrep "Only one" actual
 '
 
-test_expect_success 'fail if attr magic is used places not implemented' '
+test_expect_success 'fail if attr magic is used in places not implemented' '
 	# The main purpose of this test is to check that we actually fail
 	# when you attempt to use attr magic in commands that do not implement
-	# attr magic. This test does not advocate git-add to stay that way,
-	# though, but git-add is convenient as it has its own internal pathspec
-	# parsing.
-	test_must_fail git add ":(attr:labelB)" 2>actual &&
+	# attr magic. This test does not advocate stash push to stay that way.
+	# When you teach the command to grok the pathspec, you need to find
+	# another commnad to replace it for the test.
+	test_must_fail git stash push ":(attr:labelB)" 2>actual &&
+	test_i18ngrep "magic not supported" actual
+'
+
+test_expect_success 'fail if attr magic is used in --pathspec-from-file when not implemented' '
+	# This is like the test above but for attr magic pass in via --pathspec-from-file.
+	cat <<-\EOF >pathspec_file &&
+	:(attr:labelB)
+	EOF
+	test_must_fail git stash push --pathspec-from-file=pathspec_file 2>actual &&
 	test_i18ngrep "magic not supported" actual
 '
 
+test_expect_success 'check that attr magic works for git add --all' '
+	cat <<-\EOF >expect &&
+	sub/newFileA-foo
+	EOF
+	>sub/newFileA-foo &&
+	>sub/newFileB-foo &&
+	git add --all ":(exclude,attr:labelB)" &&
+	git diff --name-only --cached >actual &&
+	git restore -W -S . &&
+	test_cmp expect actual
+'
+
+test_expect_success 'check that attr magic works for git add -u' '
+	cat <<-\EOF >expect &&
+	sub/fileA
+	EOF
+	>sub/newFileA-foo &&
+	>sub/newFileB-foo &&
+	>sub/fileA &&
+	>sub/fileB &&
+	git add -u ":(exclude,attr:labelB)" &&
+	git diff --name-only --cached  >actual &&
+	git restore -S -W . && rm sub/new* &&
+	test_cmp expect actual
+'
+
+test_expect_success 'check that attr magic works for git add <path>' '
+	cat <<-\EOF >expect &&
+	fileA
+	fileB
+	sub/fileA
+	EOF
+	>fileA &&
+	>fileB &&
+	>sub/fileA &&
+	>sub/fileB &&
+	git add ":(exclude,attr:labelB)sub/*" &&
+	git diff --name-only --cached >actual &&
+	git restore -S -W . &&
+	test_cmp expect actual
+'
+
+test_expect_success 'check that attr magic works for git -add .' '
+	cat <<-\EOF >expect &&
+	sub/fileA
+	EOF
+	>fileA &&
+	>fileB &&
+	>sub/fileA &&
+	>sub/fileB &&
+	cd sub &&
+	git add . ":(exclude,attr:labelB)" &&
+	cd .. &&
+	git diff --name-only --cached >actual &&
+	git restore -S -W . &&
+	test_cmp expect actual
+'
+
+test_expect_success 'check that attr magic works for git add --pathspec-from-file' '
+	cat <<-\EOF >pathspec_file &&
+	:(exclude,attr:labelB)
+	EOF
+	cat <<-\EOF >expect &&
+	sub/newFileA-foo
+	EOF
+	>sub/newFileA-foo &&
+	>sub/newFileB-foo &&
+	git add --all --pathspec-from-file=pathspec_file &&
+	git diff --name-only --cached >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'check that attr magic works for git' '
+'
+
 test_expect_success 'abort on giving invalid label on the command line' '
 	test_must_fail git ls-files . ":(attr:☺)"
 '