Bazel: git_repository skylark rule regression in bazel 0.10.0rc7

Created on 29 Jan 2018 · 29Comments · Source: bazelbuild/bazel

Description of the problem / feature request:

git_repository pointing at a commit which is not the latest commit in the repo causes error because of git clone --depth 1. This is currently blocking us from upgrading to bazel 0.10.0.

Bugs: what's the simplest, easiest way to reproduce this bug? Please provide a minimal example if possible.

Clone https://github.com/wix-playground/repoA
Run bazel build //... (with 0.10.0rc7)

Note this line points at a non-HEAD commit of repoB.

What operating system are you running Bazel on?

MacOS 10.12.6 & Debian8

What's the output of `bazel info release`?

release 0.10.0rc7

Have you found anything relevant by searching the web?

https://github.com/bazelbuild/bazel/commit/4f51c0849305e9bfff2af4d80792fc69c02dfa08#diff-837a9f01631c2638001dbb9c581868ad

Any other information, logs, or outputs that you want to share?

▶ bazel build //...
ERROR: error loading package '': Encountered error while reading extension file 'whatever.bzl': no such package '@repoB//': Traceback (most recent call last):
    File "/private/var/tmp/_bazel_alonbl/46478dd6ac03b1b47726754e0c4e0fa0/external/bazel_tools/tools/build_defs/repo/git.bzl", line 69
        _clone_or_update(ctx)
    File "/private/var/tmp/_bazel_alonbl/46478dd6ac03b1b47726754e0c4e0fa0/external/bazel_tools/tools/build_defs/repo/git.bzl", line 44, in _clone_or_update
        fail(("error cloning %s:\n%s" % (ctx....)))
error cloning repoB:
+ cd /private/var/tmp/_bazel_alonbl/46478dd6ac03b1b47726754e0c4e0fa0/external
+ rm -rf /private/var/tmp/_bazel_alonbl/46478dd6ac03b1b47726754e0c4e0fa0/external/repoB
+ git clone --depth=1 [email protected]:wix-playground/repoB.git /private/var/tmp/_bazel_alonbl/46478dd6ac03b1b47726754e0c4e0fa0/external/repoB
Cloning into '/private/var/tmp/_bazel_alonbl/46478dd6ac03b1b47726754e0c4e0fa0/external/repoB'...
+ cd /private/var/tmp/_bazel_alonbl/46478dd6ac03b1b47726754e0c4e0fa0/external/repoB
+ git reset --hard 735e089f501c182560c4df2451bd16011fd09113
fatal: Could not parse object '735e089f501c182560c4df2451bd16011fd09113'.
+ git fetch --depth=1 origin 735e089f501c182560c4df2451bd16011fd09113:735e089f501c182560c4df2451bd16011fd09113
ERROR: error loading package '': Encountered error while reading extension file 'whatever.bzl': no such package '@repoB//': Traceback (most recent call last):
    File "/private/var/tmp/_bazel_alonbl/46478dd6ac03b1b47726754e0c4e0fa0/external/bazel_tools/tools/build_defs/repo/git.bzl", line 69
        _clone_or_update(ctx)
    File "/private/var/tmp/_bazel_alonbl/46478dd6ac03b1b47726754e0c4e0fa0/external/bazel_tools/tools/build_defs/repo/git.bzl", line 44, in _clone_or_update
        fail(("error cloning %s:\n%s" % (ctx....)))
error cloning repoB:
+ cd /private/var/tmp/_bazel_alonbl/46478dd6ac03b1b47726754e0c4e0fa0/external
+ rm -rf /private/var/tmp/_bazel_alonbl/46478dd6ac03b1b47726754e0c4e0fa0/external/repoB
+ git clone --depth=1 [email protected]:wix-playground/repoB.git /private/var/tmp/_bazel_alonbl/46478dd6ac03b1b47726754e0c4e0fa0/external/repoB
Cloning into '/private/var/tmp/_bazel_alonbl/46478dd6ac03b1b47726754e0c4e0fa0/external/repoB'...
+ cd /private/var/tmp/_bazel_alonbl/46478dd6ac03b1b47726754e0c4e0fa0/external/repoB
+ git reset --hard 735e089f501c182560c4df2451bd16011fd09113
fatal: Could not parse object '735e089f501c182560c4df2451bd16011fd09113'.
+ git fetch --depth=1 origin 735e089f501c182560c4df2451bd16011fd09113:735e089f501c182560c4df2451bd16011fd09113
INFO: Elapsed time: 5.505s
FAILED: Build did NOT complete successfully (0 packages loaded)

P1 release blocker bug

Source

barlevalon

All 29 comments

When this happened previously (see #4405, #4358) the root cause was that the output base was itself inside a git repository, and this confused git as to where the root of the git repository was located. Could that be the issue you are seeing?

I had thought that 0ba8307ff46746864e357d0b7834b3c4247421d0 was in the 0.10.0rc7 branch, I'll go verify that now.

Can you please run the test //src/test/shell/bazel:skylark_git_repository_test and see if that shows the same failure?

katre on 29 Jan 2018

$ git branch --contains 0ba8307ff46746864e357d0b7834b3c4247421d0
  master
* release-0.10.0

So yes, the fix for the previous issue is already in the 0.10.0 rc, so the problem you are seeing may be slightly different.

katre on 29 Jan 2018

My output base is _not_ itself inside a git repository and //src/test/shell/bazel:skylark_git_repository_test passes for me.

barlevalon on 29 Jan 2018

So, testing the git commands manually, I see the same error:

jcater@jcater:~/repos$ git clone --depth=1 [email protected]:wix-playground/repoB.git
Cloning into 'repoB'...
remote: Counting objects: 5, done.
remote: Compressing objects: 100% (2/2), done.
remote: Total 5 (delta 0), reused 4 (delta 0), pack-reused 0
Receiving objects: 100% (5/5), done.
jcater@jcater:~/repos$ cd repoB/
jcater@jcater:~/repos/repoB:master$ git reset --hard 735e089f501c182560c4df2451bd16011fd09113
fatal: Could not parse object '735e089f501c182560c4df2451bd16011fd09113'.

If I remove the --depth=1 flag from the git clone command, then the git reset works. It looks like this was added in 512b9b9b353bcabc436a87329fadd449c684c44b.

I'll take a look at a quick fix, and if that doesn't work I'll see if we can revert the commit entirely.

katre on 29 Jan 2018

👍1

@edbaunton Can you explain the purpose of the --depth=1 flag? It looks like it's to limit the amount of history downloaded, but it's stopping git_repository from using any commit older than the first, so I plan to just remove it until we can find a better solution.

katre on 29 Jan 2018

Sent https://bazel-review.googlesource.com/c/bazel/+/35091 to fix this.

katre on 29 Jan 2018

It was to improve performance; the related issue was https://github.com/bazelbuild/bazel/issues/4359 since you download a lot of unneeded data which is especially painful for large repositories.

There was obviously not a test case to catch this, so will introduce a test case and then try and find a fix for the issue.

edbaunton on 29 Jan 2018

Thanks, my patch just removes the depth flag, which obviously isn't great long term.

I tried to add a test, but it appears that depth is only used with actual network downloads. Even using file:// urls didn't take --depth=1 into account.

katre on 29 Jan 2018

The patch looks good.

edbaunton on 29 Jan 2018

btw, important to say we really want @edbaunton's change since it can be a significant gain.
Just need to think how to do it.
I'd guess that if we can not fail when the git reset fails but fallback to the fetch then the flow should work.
@katre re testing- have you considered starting a lean git server for the test?

ittaiz on 30 Jan 2018

Is there a workaround for this? The patch doesn't seem to be the solution here. I wanted to release tomorrow, but if another cherry pick is needed to fix this issue I would like to cherry pick it ASAP.

cc: @aehlig any ideas?

iirina on 30 Jan 2018

Why do you think the patch doesn't seem to be the solution?

ittaiz on 30 Jan 2018

Because the --depth flag fixes https://github.com/bazelbuild/bazel/issues/4359, which is something that people want in 0.10.0.

iirina on 30 Jan 2018

I know. What @katre did was effectively a revert of 4f51c0849305e9bfff2af4d80792fc69c02dfa08. I guess it's up to you if you'd rather delay the release or lose the feature.
As I said we're also interested in the feature so if we can get both I'd be a happy camper :)

ittaiz on 30 Jan 2018

I can't see any easy fix to get this feature back so not worth delaying the release IMO. Reading https://stackoverflow.com/questions/31278902/how-to-shallow-clone-a-specific-commit-with-depth-1 there is no way to get away with using a specific sha without cloning the entire repository (that isn't server-side dependent).

In this specific instance you can use the github interface to grab https://github.com/wix-playground/repoB/archive/735e089f501c182560c4df2451bd16011fd09113.tar.gz without the interim use of git but obviously that isn't generic (but would solve the speed issue that @ittaiz is having).

In the future we might want to use the --no-local flag on the clone which I think would have found this issue here during testing (but would impose a small performance overhead when cloning local repositories).

edbaunton on 30 Jan 2018

On Tue, Jan 30, 2018 at 10:56:34AM +0000, Ed Baunton wrote:

Reading https://stackoverflow.com/questions/31278902/how-to-shallow-clone-a-specific-commit-with-depth-1 there is no way to get away with using a specific sha without cloning the entire repository (that isn't server-side dependent).

If we knew the commit date of the commit in question, a significant amount of traffic could be saved using --shallow-since, fetching only changes since the day of the commit. Maybe adding the commit date as an optional argument (used to shallow clone, if given) could be a good interim solution?

--
Klaus Aehlig
Google Germany GmbH, Erika-Mann-Str. 33, 80636 Muenchen
Registergericht und -nummer: Hamburg, HRB 86891
Sitz der Gesellschaft: Hamburg
Geschaeftsfuehrer: Paul Terence Manicle, Halimah DeLaine Prado

aehlig on 30 Jan 2018

One other solution is to first attempt a --depth 1 and if that fails fallback to a full clone and fetch. This would make you pay a price on doing a full clone of a failed low depth attempt.

edbaunton on 30 Jan 2018

One other solution is to first attempt a --depth 1 and if that fails fallback to a full clone and fetch. This would make you pay a price on doing a full clone of a failed low depth attempt.

If retrying on failure, we could also try deepen the shallow clone until it is deep enough to contain the commit we need...

aehlig on 30 Jan 2018

I just did a very unscientific test of that approach to get to the first commit in the wix repo (about 10 commits from the tip):

time $( i=1; while [ 1 ]; do rm -rf repoB;  git clone --depth $i https://github.com/wix-playground/repoB.git && git -C repoB checkout 4bfc06f0054c430f6468fe3e3c5fa523efcafe7f; if [ $? -eq 0 ]; then break; fi; i=$((i+1)); done)

which took approximately the same amount of time as cloning the entire repo alone (2 seconds). That is, repeatedly searching the history for the commit in question degenerates in performance as you have to go further back in time.

I guess we could have a heuristic and give n attempts and otherwise fallback to cloning the entire repo.

edbaunton on 30 Jan 2018

Release update: since #4359 was not a regression issue but a feature request, it shouldn't have priority over a regression issue which blocks users to upgrade to bazel 0.10.0.

That said, I will merge and cherry pick the revert of --depth flag. After that, you are free to solve this another way.

iirina on 30 Jan 2018

Fine with me, apologies for the bug.

edbaunton on 30 Jan 2018

Sounds good to me.

On Tue, Jan 30, 2018 at 9:11 AM Ed Baunton notifications@github.com wrote:

Fine with me, apologies for the bug.

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katre on 30 Jan 2018

With 0.10.0rc8 I get the following:

▶ ~/bin/bazel build //...
ERROR: error loading package '': Encountered error while reading extension file 'whatever.bzl': no such package '@repoB//': Traceback (most recent call last):
    File "/private/var/tmp/_bazel_alonbl/46478dd6ac03b1b47726754e0c4e0fa0/external/bazel_tools/tools/build_defs/repo/git.bzl", line 69
        _clone_or_update(ctx)
    File "/private/var/tmp/_bazel_alonbl/46478dd6ac03b1b47726754e0c4e0fa0/external/bazel_tools/tools/build_defs/repo/git.bzl", line 27, in _clone_or_update
        ctx.execute(["bash", "-c", "\nset -ex\n( cd ...)])
    File "/private/var/tmp/_bazel_alonbl/46478dd6ac03b1b47726754e0c4e0fa0/external/bazel_tools/tools/build_defs/repo/git.bzl", line 27, in ctx.execute
        "\nset -ex\n( cd {working_dir} &&\n    if ! ( cd '{dir_link}' && [[ \"$(git rev-parse --git-dir)\" == '.git' ]] ) >/dev/null 2>&1; then\n      rm -rf '{directory}' '{dir_link}'\n      git clone '{remote}' '{directory}'\n    fi\n    cd '{directory}'\n    git reset --hard {ref} || (git fetch origin {ref}:{ref} && git reset --hard {ref})\n    git clean -xdf )\n  ".format(working_dir = ctx.path(".").dirn..., <3 more arguments>)
Missing argument 'dir_link'
ERROR: error loading package '': Encountered error while reading extension file 'whatever.bzl': no such package '@repoB//': Traceback (most recent call last):
    File "/private/var/tmp/_bazel_alonbl/46478dd6ac03b1b47726754e0c4e0fa0/external/bazel_tools/tools/build_defs/repo/git.bzl", line 69
        _clone_or_update(ctx)
    File "/private/var/tmp/_bazel_alonbl/46478dd6ac03b1b47726754e0c4e0fa0/external/bazel_tools/tools/build_defs/repo/git.bzl", line 27, in _clone_or_update
        ctx.execute(["bash", "-c", "\nset -ex\n( cd ...)])
    File "/private/var/tmp/_bazel_alonbl/46478dd6ac03b1b47726754e0c4e0fa0/external/bazel_tools/tools/build_defs/repo/git.bzl", line 27, in ctx.execute
        "\nset -ex\n( cd {working_dir} &&\n    if ! ( cd '{dir_link}' && [[ \"$(git rev-parse --git-dir)\" == '.git' ]] ) >/dev/null 2>&1; then\n      rm -rf '{directory}' '{dir_link}'\n      git clone '{remote}' '{directory}'\n    fi\n    cd '{directory}'\n    git reset --hard {ref} || (git fetch origin {ref}:{ref} && git reset --hard {ref})\n    git clean -xdf )\n  ".format(working_dir = ctx.path(".").dirn..., <3 more arguments>)
Missing argument 'dir_link'
INFO: Elapsed time: 0.459s
FAILED: Build did NOT complete successfully (0 packages loaded)

barlevalon on 30 Jan 2018

Yes, I didn't resolve a conflict well. Will fix that...

iirina on 30 Jan 2018

@barlevalon do you mind trying again with RC8? https://releases.bazel.build/0.10.0/rc8/index.html

iirina on 30 Jan 2018

Irina,
Did you override rc8 somehow? Because Alon said he tested with rc8
On Tue, 30 Jan 2018 at 19:55 Irina Iancu notifications@github.com wrote:

@barlevalon https://github.com/barlevalon do you mind trying again with
RC8? https://releases.bazel.build/0.10.0/rc8/index.html

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ittaiz on 30 Jan 2018

Never mind. Saw the other thread.
On Tue, 30 Jan 2018 at 20:44 ittai zeidman ittaiz@gmail.com wrote:

Irina,
Did you override rc8 somehow? Because Alon said he tested with rc8
On Tue, 30 Jan 2018 at 19:55 Irina Iancu notifications@github.com wrote:

@barlevalon https://github.com/barlevalon do you mind trying again
with RC8? https://releases.bazel.build/0.10.0/rc8/index.html

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ittaiz on 30 Jan 2018

Yes I did. There was no point in having a broken RC.

iirina on 30 Jan 2018

Looks good now. 👌

barlevalon on 30 Jan 2018

🎉1

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Bazel: git_repository skylark rule regression in bazel 0.10.0rc7

Description of the problem / feature request:

Bugs: what's the simplest, easiest way to reproduce this bug? Please provide a minimal example if possible.

What operating system are you running Bazel on?

What's the output of bazel info release?

Have you found anything relevant by searching the web?

Any other information, logs, or outputs that you want to share?

All 29 comments

Related issues

What's the output of `bazel info release`?