threads / patch / 51767

patch, 2 partslist-objects-filter: handle unresolved sparse filter OID

Subject: [PATCH 2/2] list-objects-filter: handle unresolved sparse filter OID

## tl;dr

8 messages between Aug 28, 2019 and Aug 29, 2019. Diffs are folded; open one to read it.

replies: 7people: 4as markdown or json

Jon Simons· Aug 28, 2019, 20:18 UTC · lore

[PATCH 0/2] partial-clone: fix two issues with sparse filter handling

Included here are two fixes for partial cloning with sparse filters. These issues were uncovered in early testing internally at GitHub, where Taylor and Peff have provided early offlist review feedback.

Jon Simons (2):
  list-objects-filter: only parse sparse OID when 'have_git_dir'
  list-objects-filter: handle unresolved sparse filter OID
 list-objects-filter-options.c |  3 ++-
 list-objects-filter.c         |  6 +++++-
 t/t5616-partial-clone.sh      | 30 ++++++++++++++++++++++++++++++
 3 files changed, 37 insertions(+), 2 deletions(-)
-- 
2.23.0.37.g745f681289.dirty
Jon Simons· Aug 28, 2019, 20:18 UTC · re: Jon Simons · lore

Handle a potential NULL 'sparse_oid_value' when attempting to load sparse filter exclusions by blob, to avoid segfaulting later during 'add_excludes_from_blob_to_list'.

While here, uniquify the errors emitted to distinguish between the case that a given OID is NULL due to an earlier failure to resolve it, and when an OID resolves but parsing the sparse filter spec fails.

t5616 is updated to demonstrate the change.
Co-authored-by: Jeff King <peff@peff.net>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Jon Simons <jon@jonsimons.org>
---
 list-objects-filter.c    | 6 +++++-
 t/t5616-partial-clone.sh | 7 +++++++
 2 files changed, 12 insertions(+), 1 deletion(-)
Show changes to 2 files +12 −1

list-objects-filter.c, t/t5616-partial-clone.sh

diff --git a/list-objects-filter.c b/list-objects-filter.c
index 36e1f774bc..252fae5d4e 100644
--- a/list-objects-filter.c
+++ b/list-objects-filter.c
@@ -464,9 +464,13 @@ static void *filter_sparse_oid__init(
 {
 	struct filter_sparse_data *d = xcalloc(1, sizeof(*d));
 	d->omits = omitted;
+	if (!filter_options->sparse_oid_value)
+		die(_("unable to read sparse filter specification from %s"),
+		      filter_options->filter_spec);
 	if (add_excludes_from_blob_to_list(filter_options->sparse_oid_value,
 					   NULL, 0, &d->el) < 0)
-		die("could not load filter specification");
+		die(_("unable to parse sparse filter data in %s"),
+		      oid_to_hex(filter_options->sparse_oid_value));
 
 	ALLOC_GROW(d->array_frame, d->nr + 1, d->alloc);
 	d->array_frame[d->nr].defval = 0; /* default to include */
diff --git a/t/t5616-partial-clone.sh b/t/t5616-partial-clone.sh
index 6c3aa06973..0adb11f17b 100755
--- a/t/t5616-partial-clone.sh
+++ b/t/t5616-partial-clone.sh
@@ -264,6 +264,13 @@ test_expect_success 'partial clone with sparse filter succeeds' '
 	git clone --no-local --no-checkout --filter=sparse:oid=master:odd-files "file://$(pwd)/sparse-src" pc-odd
 '
 
+test_expect_success 'partial clone with unresolvable sparse filter fails cleanly' '
+	test_must_fail git clone --no-local --no-checkout --filter=sparse:oid=master:sparse-filter "file://$(pwd)/sparse-src" sc1 2>err &&
+	test_i18ngrep "unable to read sparse filter specification from sparse:oid=master:sparse-filter" err &&
+	test_must_fail git clone --no-local --no-checkout --filter=sparse:oid=master "file://$(pwd)/sparse-src" sc2 2>err &&
+	test_i18ngrep "unable to parse sparse filter data in $(git -C sparse-src rev-parse master)" err
+'
+
 . "$TEST_DIRECTORY"/lib-httpd.sh
 start_httpd
 

-- 
2.23.0.37.g745f681289.dirty
Derrick Stolee· Aug 29, 2019, 13:12 UTC · re: Jon Simons · lore

Re: [PATCH 2/2] list-objects-filter: handle unresolved sparse filter OID

On 8/28/2019 4:18 PM, Jon Simons wrote:
Show 7 quoted lines
> Handle a potential NULL 'sparse_oid_value' when attempting to load
> sparse filter exclusions by blob, to avoid segfaulting later during
> 'add_excludes_from_blob_to_list'.
> 
> While here, uniquify the errors emitted to distinguish between the
> case that a given OID is NULL due to an earlier failure to resolve it,
> and when an OID resolves but parsing the sparse filter spec fails.
Adding localization here also seems like a good idea. Thanks!
-Stolee
Show 5 quoted lines
> +test_expect_success 'partial clone with unresolvable sparse filter fails cleanly' '
> +	test_must_fail git clone --no-local --no-checkout --filter=sparse:oid=master:sparse-filter "file://$(pwd)/sparse-src" sc1 2>err &&
> +	test_i18ngrep "unable to read sparse filter specification from sparse:oid=master:sparse-filter" err &&
> +	test_must_fail git clone --no-local --no-checkout --filter=sparse:oid=master "file://$(pwd)/sparse-src" sc2 2>err &&
> +	test_i18ngrep "unable to parse sparse filter data in $(git -C sparse-src rev-parse master)" err

Just as a sanity check: when we use test_i18ngrep, how does it know how to separate the part that is translated and which part is not?

	translated: "unable to read sparse filter specification from"
	not translated: "sparse:oid=master"

Thanks, -Stolee

Jeff King· Aug 29, 2019, 13:44 UTC · re: Derrick Stolee · lore

Re: [PATCH 2/2] list-objects-filter: handle unresolved sparse filter OID

On Thu, Aug 29, 2019 at 09:12:38AM -0400, Derrick Stolee wrote:
Show 11 quoted lines
> > +test_expect_success 'partial clone with unresolvable sparse filter fails cleanly' '
> > +	test_must_fail git clone --no-local --no-checkout --filter=sparse:oid=master:sparse-filter "file://$(pwd)/sparse-src" sc1 2>err &&
> > +	test_i18ngrep "unable to read sparse filter specification from sparse:oid=master:sparse-filter" err &&
> > +	test_must_fail git clone --no-local --no-checkout --filter=sparse:oid=master "file://$(pwd)/sparse-src" sc2 2>err &&
> > +	test_i18ngrep "unable to parse sparse filter data in $(git -C sparse-src rev-parse master)" err
> 
> Just as a sanity check: when we use test_i18ngrep, how does it know how to
> separate the part that is translated and which part is not?
> 
> 	translated: "unable to read sparse filter specification from"
> 	not translated: "sparse:oid=master"

It doesn't know. By default we run the suite in LOCALE=C and it checks the whole string. Under a GETTEXT_POISON build, it checks nothing at all.

The poison stuff is really about helping people not accidentally mark a plumbing string (that we expect to get parsed by a machine) as translatable. So the idea is you'd build with GETTEXT_POISON and then run the test suite to see if anything breaks. But that means we also have to annotate the test suite with "yes, I know this will be gibberish in a poison build, but that's OK because it's meant for humans". And that's what test_i18ngrep is.

test_i18ngrep could be more clever about matching the gibberish, but there's not much point. The LOCALE=C run already covered the correctness of checking the message.

-Peff
Derrick Stolee· Aug 29, 2019, 14:28 UTC · re: Jeff King · lore

Re: [PATCH 2/2] list-objects-filter: handle unresolved sparse filter OID

On 8/29/2019 9:44 AM, Jeff King wrote:
Show 29 quoted lines
> On Thu, Aug 29, 2019 at 09:12:38AM -0400, Derrick Stolee wrote:
> 
>>> +test_expect_success 'partial clone with unresolvable sparse filter fails cleanly' '
>>> +	test_must_fail git clone --no-local --no-checkout --filter=sparse:oid=master:sparse-filter "file://$(pwd)/sparse-src" sc1 2>err &&
>>> +	test_i18ngrep "unable to read sparse filter specification from sparse:oid=master:sparse-filter" err &&
>>> +	test_must_fail git clone --no-local --no-checkout --filter=sparse:oid=master "file://$(pwd)/sparse-src" sc2 2>err &&
>>> +	test_i18ngrep "unable to parse sparse filter data in $(git -C sparse-src rev-parse master)" err
>>
>> Just as a sanity check: when we use test_i18ngrep, how does it know how to
>> separate the part that is translated and which part is not?
>>
>> 	translated: "unable to read sparse filter specification from"
>> 	not translated: "sparse:oid=master"
> 
> It doesn't know. By default we run the suite in LOCALE=C and it checks
> the whole string. Under a GETTEXT_POISON build, it checks nothing at
> all.
> 
> The poison stuff is really about helping people not accidentally mark a
> plumbing string (that we expect to get parsed by a machine) as
> translatable. So the idea is you'd build with GETTEXT_POISON and then
> run the test suite to see if anything breaks. But that means we also
> have to annotate the test suite with "yes, I know this will be gibberish
> in a poison build, but that's OK because it's meant for humans". And
> that's what test_i18ngrep is.
> 
> test_i18ngrep could be more clever about matching the gibberish, but
> there's not much point. The LOCALE=C run already covered the correctness
> of checking the message.
Thanks for clearing this up for me!
-Stolee
Jon Simons· Aug 28, 2019, 20:18 UTC · re: Jon Simons · lore

[PATCH 1/2] list-objects-filter: only parse sparse OID when 'have_git_dir'

Fix a bug in partial cloning with sparse filters by ensuring to check for 'have_git_dir' before attempting to resolve the sparse filter OID.

Otherwise the client will trigger:
    BUG: refs.c:1851: attempting to get main_ref_store outside of repository
when attempting to git clone with a sparse filter.

Note that this fix is the minimal one which avoids the BUG and allows for the clone to complete successfully:

There is an open question as to whether there should be any attempt to resolve the OID provided by the client in this context, as a filter for the clone to be used on the remote side. For cases where local and remote OID resolutions differ, resolving on the client side could be considered a bug. For now, the minimal approach here is used to unblock further testing for partial clones with sparse filters, while a more invasive fix could make sense to pursue as a future direction.

t5616 is updated to demonstrate the change.
Signed-off-by: Jon Simons <jon@jonsimons.org>
---
 list-objects-filter-options.c |  3 ++-
 t/t5616-partial-clone.sh      | 23 +++++++++++++++++++++++
 2 files changed, 25 insertions(+), 1 deletion(-)
Show changes to 2 files +25 −1

list-objects-filter-options.c, t/t5616-partial-clone.sh

diff --git a/list-objects-filter-options.c b/list-objects-filter-options.c
index 1cb20c659c..aaba312edb 100644
--- a/list-objects-filter-options.c
+++ b/list-objects-filter-options.c
@@ -71,7 +71,8 @@ static int gently_parse_list_objects_filter(
 		 * command, but DO NOT complain if we don't have the blob or
 		 * ref locally.
 		 */
-		if (!get_oid_with_context(the_repository, v0, GET_OID_BLOB,
+		if (have_git_dir() &&
+		    !get_oid_with_context(the_repository, v0, GET_OID_BLOB,
 					  &sparse_oid, &oc))
 			filter_options->sparse_oid_value = oiddup(&sparse_oid);
 		filter_options->choice = LOFC_SPARSE_OID;
diff --git a/t/t5616-partial-clone.sh b/t/t5616-partial-clone.sh
index 565254558f..6c3aa06973 100755
--- a/t/t5616-partial-clone.sh
+++ b/t/t5616-partial-clone.sh
@@ -241,6 +241,29 @@ test_expect_success 'fetch what is specified on CLI even if already promised' '
 	! grep "?$(cat blob)" missing_after
 '
 
+test_expect_success 'setup src repo for sparse filter' '
+	git init sparse-src &&
+	git -C sparse-src config --local uploadpack.allowfilter 1 &&
+	git -C sparse-src config --local uploadpack.allowanysha1inwant 1 &&
+	for n in 1 2 3 4
+	do
+		test_commit -C sparse-src "this-is-file-$n" file.$n.txt
+	done &&
+	echo "/file.1.txt" >> sparse-src/odd-files &&
+	echo "/file.3.txt" >> sparse-src/odd-files &&
+	echo "/file.2.txt" >> sparse-src/even-files &&
+	echo "/file.4.txt" >> sparse-src/even-files &&
+	echo "/*" >> sparse-src/all-files &&
+	git -C sparse-src add odd-files even-files all-files &&
+	git -C sparse-src commit -m "some sparse checkout files"
+'
+
+test_expect_success 'partial clone with sparse filter succeeds' '
+	git clone --no-local --no-checkout --filter=sparse:oid=master:all-files "file://$(pwd)/sparse-src" pc-all &&
+	git clone --no-local --no-checkout --filter=sparse:oid=master:even-files "file://$(pwd)/sparse-src" pc-even &&
+	git clone --no-local --no-checkout --filter=sparse:oid=master:odd-files "file://$(pwd)/sparse-src" pc-odd
+'
+
 . "$TEST_DIRECTORY"/lib-httpd.sh
 start_httpd
 

-- 
2.23.0.37.g745f681289.dirty
Eric Sunshine· Aug 28, 2019, 21:10 UTC · re: Jon Simons · lore

Re: [PATCH 1/2] list-objects-filter: only parse sparse OID when 'have_git_dir'

On Wed, Aug 28, 2019 at 4:27 PM Jon Simons <jon@jonsimons.org> wrote:
Show 15 quoted lines
> Fix a bug in partial cloning with sparse filters by ensuring to check
> for 'have_git_dir' before attempting to resolve the sparse filter OID.
> [...]
> Signed-off-by: Jon Simons <jon@jonsimons.org>
> ---
> diff --git a/t/t5616-partial-clone.sh b/t/t5616-partial-clone.sh
> @@ -241,6 +241,29 @@ test_expect_success 'fetch what is specified on CLI even if already promised' '
> +test_expect_success 'setup src repo for sparse filter' '
> +       git init sparse-src &&
> +       git -C sparse-src config --local uploadpack.allowfilter 1 &&
> +       git -C sparse-src config --local uploadpack.allowanysha1inwant 1 &&
> +       for n in 1 2 3 4
> +       do
> +               test_commit -C sparse-src "this-is-file-$n" file.$n.txt
> +       done &&

The way this is coded, a failure of the test_commit() invocation won't fail the test overall. You need to do so manually:

    for n in 1 2 3 4
    do
        test_commit -C sparse-src "this-is-file-$n" file.$n.txt || return 1
    done &&
> +       echo "/file.1.txt" >> sparse-src/odd-files &&
> +       echo "/file.3.txt" >> sparse-src/odd-files &&
> +       echo "/file.2.txt" >> sparse-src/even-files &&
> +       echo "/file.4.txt" >> sparse-src/even-files &&
Simpler:
    test_write_lines /file1.txt /file3.txt >sparse-src/odd-files &&
    test_write_lines /file2.txt /file4.txt >sparse-src/even-files &&
> +       echo "/*" >> sparse-src/all-files &&
Style nit: drop whitespace following redirection operator.

And, using >> rather than just > here makes the test more confusing than it need be; probably best to use >.

Jeff King· Aug 28, 2019, 23:35 UTC · re: Jon Simons · lore

Re: [PATCH 1/2] list-objects-filter: only parse sparse OID when 'have_git_dir'

On Wed, Aug 28, 2019 at 04:18:23PM -0400, Jon Simons wrote:
Show 19 quoted lines
> Fix a bug in partial cloning with sparse filters by ensuring to check
> for 'have_git_dir' before attempting to resolve the sparse filter OID.
> 
> Otherwise the client will trigger:
> 
>     BUG: refs.c:1851: attempting to get main_ref_store outside of repository
> 
> when attempting to git clone with a sparse filter.
> 
> Note that this fix is the minimal one which avoids the BUG and allows
> for the clone to complete successfully:
> 
> There is an open question as to whether there should be any attempt
> to resolve the OID provided by the client in this context, as a filter
> for the clone to be used on the remote side.  For cases where local
> and remote OID resolutions differ, resolving on the client side could
> be considered a bug.  For now, the minimal approach here is used to
> unblock further testing for partial clones with sparse filters, while
> a more invasive fix could make sense to pursue as a future direction.

Just to provide a little more of our findings to the list: I think the main thing going on here is that the filter options-parsing code is shared on the client and server side (and doesn't have any idea which it is). That's why we see the "do not complain" comment in the context below:

Show 10 quoted lines
> --- a/list-objects-filter-options.c
> +++ b/list-objects-filter-options.c
> @@ -71,7 +71,8 @@ static int gently_parse_list_objects_filter(
>  		 * command, but DO NOT complain if we don't have the blob or
>  		 * ref locally.
>  		 */
> -		if (!get_oid_with_context(the_repository, v0, GET_OID_BLOB,
> +		if (have_git_dir() &&
> +		    !get_oid_with_context(the_repository, v0, GET_OID_BLOB,
>  					  &sparse_oid, &oc))

and why it's OK to just quietly ignore this case. I don't think it's hurting anything in practice. Whether we resolve the name or not, we send the _original_ name to the other side (it would be a bug for us to resolve it ourselves and send the oid).

Show 5 quoted lines
> +test_expect_success 'partial clone with sparse filter succeeds' '
> +	git clone --no-local --no-checkout --filter=sparse:oid=master:all-files "file://$(pwd)/sparse-src" pc-all &&
> +	git clone --no-local --no-checkout --filter=sparse:oid=master:even-files "file://$(pwd)/sparse-src" pc-even &&
> +	git clone --no-local --no-checkout --filter=sparse:oid=master:odd-files "file://$(pwd)/sparse-src" pc-odd
> +'

Since you're using "--no-local", you should be able to just say "sparse-src" without the full path or file URL.

I think Eric's style suggestions elsewhere in the thread were sensible, too. And of course the code change itself looks good.

-Peff

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