threads / patch / 41266

patchoptionally disable gitattributes

Subject: [PATCH] optionally disable gitattributes

## tl;dr

4 messages between Jan 27, 2016 and Jan 27, 2016. Diffs are folded; open one to read it.

replies: 3people: 3as markdown or json

Clemens Buchacher· Jan 27, 2016, 09:50 UTC · lore

If committed files are not normalized, adding gitattributes has the side effect that such files are shown as modified, even though they were not actually modified by the user, and the work tree matches the committed file. This is because with gitattributes, the file is modified on the fly when git reads it from disk, before it compares with the index contents.

This is desirable in most situations, because it makes the user aware that files should be normalized. However, it can become an issue for automation. Since Git considers the work tree to be dirty, some operations such as git rebase or git cherry-pick refuse to operate. Those commands offer no flag to force overwrite work tree changes. The only options are to commit the changes, or to remove gitattributes, but that changes the repository state, which may be undesirable in a scripted context.

Introduce an environment variable GIT_ATTRIBUTES_DISABLED, which if set makes Git ignore any gitattributes.

Signed-off-by: Clemens Buchacher <drizzd@aon.at>
---
 Documentation/git.txt           |  4 ++++
 Documentation/gitattributes.txt |  6 ++++++
 attr.c                          |  3 +++
 t/t0003-attributes.sh           | 43 +++++++++++++++++++++++++++++++++++++++++
 4 files changed, 56 insertions(+)
Show changes to 4 files +56 −0

Documentation/git.txt, Documentation/gitattributes.txt, attr.c, t/t0003-attributes.sh

diff --git a/Documentation/git.txt b/Documentation/git.txt
index bff6302..00f4e3b 100644
--- a/Documentation/git.txt
+++ b/Documentation/git.txt
@@ -1132,6 +1132,10 @@ of clones and fetches.
 	  - any external helpers are named by their protocol (e.g., use
 	    `hg` to allow the `git-remote-hg` helper)
 
+'GIT_ATTRIBUTES_DISABLED'::
+	If set, attributes are disabled for all paths. See
+	linkgit:gitattributes[1] for more details on attributes.
+
 
 Discussion[[Discussion]]
 ------------------------
diff --git a/Documentation/gitattributes.txt b/Documentation/gitattributes.txt
index e3b1de8..f6a2b1d 100644
--- a/Documentation/gitattributes.txt
+++ b/Documentation/gitattributes.txt
@@ -996,6 +996,12 @@ frotz	unspecified
 ----------------------------------------------------------------
 
 
+ENVIRONMENT
+-----------
+
+GIT_ATTRIBUTES_DISABLED::
+	If set, attributes are disabled for all paths.
+
 SEE ALSO
 --------
 linkgit:git-check-attr[1].
diff --git a/attr.c b/attr.c
index 086c08d..0fa2f1a 100644
--- a/attr.c
+++ b/attr.c
@@ -547,6 +547,9 @@ static void prepare_attr_stack(const char *path, int dirlen)
 	int len;
 	const char *cp;
 
+	if (getenv("GIT_ATTRIBUTES_DISABLED"))
+		return;
+
 	/*
 	 * At the bottom of the attribute stack is the built-in
 	 * set of attribute definitions, followed by the contents
diff --git a/t/t0003-attributes.sh b/t/t0003-attributes.sh
index f0fbb42..26e6766 100755
--- a/t/t0003-attributes.sh
+++ b/t/t0003-attributes.sh
@@ -13,6 +13,14 @@ attr_check () {
 	test_line_count = 0 err
 }
 
+attr_check_disabled () {
+	(
+		GIT_ATTRIBUTES_DISABLED=t
+		export GIT_ATTRIBUTES_DISABLED
+		attr_check "$@" unspecified
+	)
+}
+
 test_expect_success 'setup' '
 	mkdir -p a/b/d a/c b &&
 	(
@@ -84,6 +92,41 @@ test_expect_success 'attribute test' '
 	attr_check a/b/d/yes unspecified
 '
 
+test_expect_success 'gitattributes disabled' '
+	attr_check_disabled f &&
+	attr_check_disabled a/f &&
+	attr_check_disabled a/c/f &&
+	attr_check_disabled a/g &&
+	attr_check_disabled a/b/g &&
+	attr_check_disabled b/g &&
+	attr_check_disabled a/b/h &&
+	attr_check_disabled a/b/d/g &&
+	attr_check_disabled onoff &&
+	attr_check_disabled offon &&
+	attr_check_disabled no &&
+	attr_check_disabled a/b/d/no &&
+	attr_check_disabled a/b/d/yes
+'
+
+test_expect_success 'no changes if gitattributes disabled' '
+	mkdir clean &&
+	git init clean &&
+	(
+		cd clean &&
+		printf "foo\r\n" >dos.txt &&
+		git add dos.txt &&
+		test_tick &&
+		git commit -q -m dos.txt &&
+		echo "*.txt text eol=lf" >.gitattributes &&
+		git add .gitattributes &&
+		test_tick &&
+		git commit -q -m .gitattributes &&
+		rm -f .git/index &&
+		git reset &&
+		GIT_ATTRIBUTES_DISABLED=t git diff --exit-code
+	)
+'
+
 test_expect_success 'attribute matching is case sensitive when core.ignorecase=0' '
 
 	test_must_fail attr_check F f "-c core.ignorecase=0" &&
-- 
2.7.0
Junio C Hamano· Jan 27, 2016, 11:59 UTC · re: Clemens Buchacher · lore

Re: [PATCH] optionally disable gitattributes

Clemens Buchacher <drizzd@aon.at> writes:
Show 21 quoted lines
> If committed files are not normalized, adding gitattributes has the
> side effect that such files are shown as modified, even though they
> were not actually modified by the user, and the work tree matches
> the committed file. This is because with gitattributes, the file is
> modified on the fly when git reads it from disk, before it compares
> with the index contents.
>
> This is desirable in most situations, because it makes the user
> aware that files should be normalized. However, it can become an
> issue for automation. Since Git considers the work tree to be
> dirty, some operations such as git rebase or git cherry-pick refuse
> to operate. Those commands offer no flag to force overwrite work
> tree changes. The only options are to commit the changes, or to
> remove gitattributes, but that changes the repository state, which
> may be undesirable in a scripted context.
>
> Introduce an environment variable GIT_ATTRIBUTES_DISABLED, which if
> set makes Git ignore any gitattributes.
>
> Signed-off-by: Clemens Buchacher <drizzd@aon.at>
> ---

Is the problem you are trying to solve related to the issue we discussed recently in a nearby thread?

That is, even after "reset --hard", if the result of converting the contents in the index to the working tree representation and then converting that result back to the normalized representation does not match what is in the index, Git would sometimes say that the working tree contents differ from the index?

I think the change in this patch has some uses, and I think the issue we discussed recently in a nearby thread indeed is a problem, but I do not think there is an impedance mismatch beween the two, so I'd like to first make sure you are trying to solve the problem I think you are trying to solve.

Torsten Bögershausen· Jan 27, 2016, 15:04 UTC · re: Junio C Hamano · lore

Re: [PATCH] optionally disable gitattributes

On 27.01.16 12:59, Junio C Hamano wrote:
Show 17 quoted lines
> Clemens Buchacher <drizzd@aon.at> writes:
> 
>> If committed files are not normalized, adding gitattributes has the
>> side effect that such files are shown as modified, even though they
>> were not actually modified by the user, and the work tree matches
>> the committed file. This is because with gitattributes, the file is
>> modified on the fly when git reads it from disk, before it compares
>> with the index contents.
>>
>> This is desirable in most situations, because it makes the user
>> aware that files should be normalized. However, it can become an
>> issue for automation. Since Git considers the work tree to be
>> dirty, some operations such as git rebase or git cherry-pick refuse
>> to operate. Those commands offer no flag to force overwrite work
>> tree changes. The only options are to commit the changes, or to
>> remove gitattributes, but that changes the repository state, which
>> may be undesirable in a scripted context.
It feels like a workaround for something that could be fixable, or is already ongoing.
Before going into more details,
could you tell us which attributes you are typically using (when having this problems) ?
Is it
* text=auto
or
*.sh text 
or something else?
Show 9 quoted lines
>>
>> Introduce an environment variable GIT_ATTRIBUTES_DISABLED, which if
>> set makes Git ignore any gitattributes.
>>
>> Signed-off-by: Clemens Buchacher <drizzd@aon.at>
>> ---
> 
> Is the problem you are trying to solve related to the issue we
> discussed recently in a nearby thread?
It seems that I missed the thread ?
Show 12 quoted lines
> 
> That is, even after "reset --hard", if the result of converting the
> contents in the index to the working tree representation and then
> converting that result back to the normalized representation does
> not match what is in the index, Git would sometimes say that the
> working tree contents differ from the index?
> 
> I think the change in this patch has some uses, and I think the
> issue we discussed recently in a nearby thread indeed is a problem,
> but I do not think there is an impedance mismatch beween the two, so
> I'd like to first make sure you are trying to solve the problem I
> think you are trying to solve.
Clemens Buchacher· Jan 27, 2016, 15:25 UTC · re: Torsten Bögershausen · lore

Re: [PATCH] optionally disable gitattributes

On Wed, Jan 27, 2016 at 04:04:39PM +0100, Torsten Bögershausen wrote:
Show 9 quoted lines
>
> It feels like a workaround for something that could be fixable, or is already ongoing.
> Before going into more details,
> could you tell us which attributes you are typically using (when having this problems) ?
> Is it
> * text=auto
> or
> *.sh text 
> or something else?

My concrete use case is the text attribute, as in your example: "*.sh text". But I think of the patch as a more general solution for cases where we want to work with the files as they are committed, without having to deal with not normalized files or other conversions due to gitattributes.

Please note that you may also want to read my reply to the other thread that Junio mentioned: [PATCH] travis-ci: run previously failed tests first, then slowest to fastest.

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