Re: [PATCH] diff: don't read index when --no-index is given
[Sorry for not seeing this before sending out v2.]
Junio C Hamano writes:
> Thomas Gummerer writes:
>
>> git diff --no-index ... currently reads the index, during setup, when
>> calling gitmodules_config(). In the usual case this gives us some
>> performance drawbacks, but it's especially annoying if there is a broken
>> index file.
>>
>> Avoid calling the unnecessary gitmodules_config() when the --no-index
>> option is given. Also add a test to guard against similar breakages in the
>> future.
>>
>> Signed-off-by: Thomas Gummerer
>> ---
>> builtin/diff.c | 13 +++--
>> t/t4053-diff-no-index.sh | 6 ++
>> 2 files changed, 17 insertions(+), 2 deletions(-)
>>
>> diff --git a/builtin/diff.c b/builtin/diff.c
>> index adb93a9..47c0833 100644
>> --- a/builtin/diff.c
>> +++ b/builtin/diff.c
>> @@ -257,7 +257,7 @@ int cmd_diff(int argc, const char **argv, const char
>> *prefix)
>> int blobs = 0, paths = 0;
>> const char *path = NULL;
>> struct blobinfo blob[2];
>> -int nongit;
>> +int nongit, no_index = 0;
>> int result = 0;
>>
>> /*
>> @@ -282,9 +282,18 @@ int cmd_diff(int argc, const char **argv, const char
>> *prefix)
>> *
>> * Other cases are errors.
>> */
>> +for (i = 1; i < argc; i++) {
>> +if (!strcmp(argv[i], "--"))
>> +break;
>> +if (!strcmp(argv[i], "--no-index")) {
>> +no_index = 1;
>> +break;
>> +}
>> +}
>
> This seems to duplicate only half the logic at the beginning of
> diff_no_index(), right? E.g., running "git diff /var/tmp/[12]"
> inside a working tree that is controlled by a Git repository when
> /var/tmp/ is outside, we do want to behave as if the command line
> were "git diff --no-index /var/tmp/[12]", but this half duplication
> makes these two behave differently, no?
Yes you're right, I missed that. "git diff /var/tmp/[12]" inside a
working tree with a broken index has the same problems, which should be
fixed too. I'll try to fix that and send a new patch afterwards.
> I think the issue you are trying to address is worth tackling, but I
> wonder if a bit of preparatory refactoring is necessary to avoid the
> partial duplication.
>
>> prefix = setup_git_directory_gently(&nongit);
>> -gitmodules_config();
>> +if (!no_index)
>> +gitmodules_config();
>> git_config(git_diff_ui_config, NULL);
>>
>> init_revisions(&rev, prefix);
>> diff --git a/t/t4053-diff-no-index.sh b/t/t4053-diff-no-index.sh
>> index 979e983..a24ae4d 100755
>> --- a/t/t4053-diff-no-index.sh
>> +++ b/t/t4053-diff-no-index.sh
>> @@ -29,4 +29,10 @@ test_expect_success 'git diff --no-index relative path
>> outside repo' '
>> )
>> '
>>
>> +test_expect_success 'git diff --no-index with broken index' '
>> +cd repo &&
>> +echo broken >.git/index &&
>> +test_expect_code 0 git diff --no-index a ../non/git/a
>> +'
>> +
>> test_done
--
Thomas
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Re: [PATCH] diff: don't read index when --no-index is given
Thomas Gummerer writes:
> git diff --no-index ... currently reads the index, during setup, when
> calling gitmodules_config(). In the usual case this gives us some
> performance drawbacks, but it's especially annoying if there is a broken
> index file.
>
> Avoid calling the unnecessary gitmodules_config() when the --no-index
> option is given. Also add a test to guard against similar breakages in the
> future.
>
> Signed-off-by: Thomas Gummerer
> ---
> builtin/diff.c | 13 +++--
> t/t4053-diff-no-index.sh | 6 ++
> 2 files changed, 17 insertions(+), 2 deletions(-)
>
> diff --git a/builtin/diff.c b/builtin/diff.c
> index adb93a9..47c0833 100644
> --- a/builtin/diff.c
> +++ b/builtin/diff.c
> @@ -257,7 +257,7 @@ int cmd_diff(int argc, const char **argv, const char
> *prefix)
> int blobs = 0, paths = 0;
> const char *path = NULL;
> struct blobinfo blob[2];
> - int nongit;
> + int nongit, no_index = 0;
> int result = 0;
>
> /*
> @@ -282,9 +282,18 @@ int cmd_diff(int argc, const char **argv, const char
> *prefix)
>*
>* Other cases are errors.
>*/
> + for (i = 1; i < argc; i++) {
> + if (!strcmp(argv[i], "--"))
> + break;
> + if (!strcmp(argv[i], "--no-index")) {
> + no_index = 1;
> + break;
> + }
> + }
This seems to duplicate only half the logic at the beginning of
diff_no_index(), right? E.g., running "git diff /var/tmp/[12]"
inside a working tree that is controlled by a Git repository when
/var/tmp/ is outside, we do want to behave as if the command line
were "git diff --no-index /var/tmp/[12]", but this half duplication
makes these two behave differently, no?
I think the issue you are trying to address is worth tackling, but I
wonder if a bit of preparatory refactoring is necessary to avoid the
partial duplication.
> prefix = setup_git_directory_gently(&nongit);
> - gitmodules_config();
> + if (!no_index)
> + gitmodules_config();
> git_config(git_diff_ui_config, NULL);
>
> init_revisions(&rev, prefix);
> diff --git a/t/t4053-diff-no-index.sh b/t/t4053-diff-no-index.sh
> index 979e983..a24ae4d 100755
> --- a/t/t4053-diff-no-index.sh
> +++ b/t/t4053-diff-no-index.sh
> @@ -29,4 +29,10 @@ test_expect_success 'git diff --no-index relative path
> outside repo' '
> )
> '
>
> +test_expect_success 'git diff --no-index with broken index' '
> + cd repo &&
> + echo broken >.git/index &&
> + test_expect_code 0 git diff --no-index a ../non/git/a
> +'
> +
> test_done
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Re: [PATCH] diff: don't read index when --no-index is given
Thomas Gummerer wrote: > For example I would take one > version, use test-dump-cache-tree to dump the cache tree to a file, > change the format slightly, use test-dump-cache-tree again, and check > the difference with "git diff --no-index". Makes a lot of sense. Thanks for explaining. Regards, Jonathan -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] diff: don't read index when --no-index is given
Jonathan Nieder writes:
> Thomas Gummerer wrote:
>
>> git diff --no-index ... currently reads the index, during setup, when
>> calling gitmodules_config(). In the usual case this gives us some
>> performance drawbacks,
>
> Makes sense.
>
>>but it's especially annoying if there is a broken
>> index file.
>
> Is this really a normal case? It makes sense that as a side-effect it
> is easier to use "git diff --no-index" as a general-purpose tool while
> investigating a broken repo, but I would have thought that quickly
> learning a repo is broken is a good thing in any case.
>
> A little more information about the context where this came up would
> be helpful, I guess.
It came up while I was working on index-v5, where I had to investigate
quite a few repositories where the index was broken, especially when I
was changing the index format slightly. For example I would take one
version, use test-dump-cache-tree to dump the cache tree to a file,
change the format slightly, use test-dump-cache-tree again, and check
the difference with "git diff --no-index".
This might not be a very common use case, but maybe the patch might help
someone else too. (In addition to the performance improvements)
I'm not sure how much diff --no-index is used normally, but when the
index is broken that would be detected relatively soon anyway. I'm not
so worried about one more command working when it's broken.
> [...]
>> --- a/builtin/diff.c
>> +++ b/builtin/diff.c
> [...]
>> @@ -282,9 +282,18 @@ int cmd_diff(int argc, const char **argv, const char
>> *prefix)
>> *
>> * Other cases are errors.
>> */
>> +for (i = 1; i < argc; i++) {
>> +if (!strcmp(argv[i], "--"))
>> +break;
>> +if (!strcmp(argv[i], "--no-index")) {
>> +no_index = 1;
>> +break;
>> +}
>
> setup_revisions() uses the same logic that doesn't handle options that
> take arguments in their "unstuck" form (e.g., "--word-diff-regex --"),
> so this is probably not a regression, though I haven't checked. :)
The same logic is used in diff_no_index(), so I think it should be fine.
> [...]
>> prefix = setup_git_directory_gently(&nongit);
>> -gitmodules_config();
>> +if (!no_index)
>> +gitmodules_config();
>
> Perhaps we can improve performance and behavior by skipping the
> setup_git_directory_gently() call, too?
>
> That would help with the repairing-broken-repository case by
> working even if .git/config or .git/HEAD is broken, and I think
> it is more intuitive that the repository-local configuration is
> ignored by "git diff --no-index". It would also help with
> performance by avoiding some filesystem access.
Yes, I think that would make sense, thanks. I tested it, and it didn't
change the performance, but it's still a good change for the broken
repository case. Will change in the re-roll and add a test for that.
> [...]
>> +test_expect_success 'git diff --no-index with broken index' '
>> +cd repo &&
>> +echo broken >.git/index &&
>> +test_expect_code 0 git diff --no-index a ../non/git/a
>
> Clever. I wouldn't use "test_expect_code 0", since that's
> already implied by including the "git diff --no-index" call
> in the && chain.
Thanks, will change. Thanks a lot for your review. Will send a re-roll
soon.
> Thanks and hope that helps,
> Jonathan
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Thomas
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Re: [PATCH] diff: don't read index when --no-index is given
Jens Lehmann wrote: > Am 09.12.2013 16:16, schrieb Jonathan Nieder: >> Thomas Gummerer wrote: >>> git diff --no-index ... currently reads the index, during setup, when >>> calling gitmodules_config(). In the usual case this gives us some >>> performance drawbacks, >> >> Makes sense. > > Hmm, but this will disable the submodule specific ignore configuration > options defined in the .gitmodules file, no? (E.g. when diffing two > directories containing submodules) Yes. That seems like a good behavior. "git diff --no-index" was invented as just a fancy version of 'diff -uR", without any awareness of the current git repository. That means that at least in principle, .gitmodules and .gitignore should not affect it. [...] > Wouldn't adding a "gently" option (which > could then warn instead of dying) to gitmodules_config() be a better > solution here? I don't think so. Thanks and hope that helps, Jonathan -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] diff: don't read index when --no-index is given
Am 09.12.2013 16:16, schrieb Jonathan Nieder: > Thomas Gummerer wrote: > >> git diff --no-index ... currently reads the index, during setup, when >> calling gitmodules_config(). In the usual case this gives us some >> performance drawbacks, > > Makes sense. Hmm, but this will disable the submodule specific ignore configuration options defined in the .gitmodules file, no? (E.g. when diffing two directories containing submodules) >>but it's especially annoying if there is a broken >> index file. > > Is this really a normal case? It makes sense that as a side-effect it > is easier to use "git diff --no-index" as a general-purpose tool while > investigating a broken repo, but I would have thought that quickly > learning a repo is broken is a good thing in any case. But I agree that dying with "index file corrupt" is a bit strange when calling diff with --no-index. Wouldn't adding a "gently" option (which could then warn instead of dying) to gitmodules_config() be a better solution here? -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] diff: don't read index when --no-index is given
Thomas Gummerer wrote:
> git diff --no-index ... currently reads the index, during setup, when
> calling gitmodules_config(). In the usual case this gives us some
> performance drawbacks,
Makes sense.
>but it's especially annoying if there is a broken
> index file.
Is this really a normal case? It makes sense that as a side-effect it
is easier to use "git diff --no-index" as a general-purpose tool while
investigating a broken repo, but I would have thought that quickly
learning a repo is broken is a good thing in any case.
A little more information about the context where this came up would
be helpful, I guess.
[...]
> --- a/builtin/diff.c
> +++ b/builtin/diff.c
[...]
> @@ -282,9 +282,18 @@ int cmd_diff(int argc, const char **argv, const char
> *prefix)
>*
>* Other cases are errors.
>*/
> + for (i = 1; i < argc; i++) {
> + if (!strcmp(argv[i], "--"))
> + break;
> + if (!strcmp(argv[i], "--no-index")) {
> + no_index = 1;
> + break;
> + }
setup_revisions() uses the same logic that doesn't handle options that
take arguments in their "unstuck" form (e.g., "--word-diff-regex --"),
so this is probably not a regression, though I haven't checked. :)
[...]
> prefix = setup_git_directory_gently(&nongit);
> - gitmodules_config();
> + if (!no_index)
> + gitmodules_config();
Perhaps we can improve performance and behavior by skipping the
setup_git_directory_gently() call, too?
That would help with the repairing-broken-repository case by
working even if .git/config or .git/HEAD is broken, and I think
it is more intuitive that the repository-local configuration is
ignored by "git diff --no-index". It would also help with
performance by avoiding some filesystem access.
[...]
> +test_expect_success 'git diff --no-index with broken index' '
> + cd repo &&
> + echo broken >.git/index &&
> + test_expect_code 0 git diff --no-index a ../non/git/a
Clever. I wouldn't use "test_expect_code 0", since that's
already implied by including the "git diff --no-index" call
in the && chain.
Thanks and hope that helps,
Jonathan
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[PATCH] diff: don't read index when --no-index is given
git diff --no-index ... currently reads the index, during setup, when
calling gitmodules_config(). In the usual case this gives us some
performance drawbacks, but it's especially annoying if there is a broken
index file.
Avoid calling the unnecessary gitmodules_config() when the --no-index
option is given. Also add a test to guard against similar breakages in the
future.
Signed-off-by: Thomas Gummerer
---
builtin/diff.c | 13 +++--
t/t4053-diff-no-index.sh | 6 ++
2 files changed, 17 insertions(+), 2 deletions(-)
diff --git a/builtin/diff.c b/builtin/diff.c
index adb93a9..47c0833 100644
--- a/builtin/diff.c
+++ b/builtin/diff.c
@@ -257,7 +257,7 @@ int cmd_diff(int argc, const char **argv, const char
*prefix)
int blobs = 0, paths = 0;
const char *path = NULL;
struct blobinfo blob[2];
- int nongit;
+ int nongit, no_index = 0;
int result = 0;
/*
@@ -282,9 +282,18 @@ int cmd_diff(int argc, const char **argv, const char
*prefix)
*
* Other cases are errors.
*/
+ for (i = 1; i < argc; i++) {
+ if (!strcmp(argv[i], "--"))
+ break;
+ if (!strcmp(argv[i], "--no-index")) {
+ no_index = 1;
+ break;
+ }
+ }
prefix = setup_git_directory_gently(&nongit);
- gitmodules_config();
+ if (!no_index)
+ gitmodules_config();
git_config(git_diff_ui_config, NULL);
init_revisions(&rev, prefix);
diff --git a/t/t4053-diff-no-index.sh b/t/t4053-diff-no-index.sh
index 979e983..a24ae4d 100755
--- a/t/t4053-diff-no-index.sh
+++ b/t/t4053-diff-no-index.sh
@@ -29,4 +29,10 @@ test_expect_success 'git diff --no-index relative path
outside repo' '
)
'
+test_expect_success 'git diff --no-index with broken index' '
+ cd repo &&
+ echo broken >.git/index &&
+ test_expect_code 0 git diff --no-index a ../non/git/a
+'
+
test_done
--
1.8.4.2
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