Currently, git patches are blindly applied with -p1 and then -p0 if that fails. There are scenarios such as core:
/README.txt
/modules/README.txt

and more commonly addition of files that could cause this approach to behave inappropriately.

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Comments

rfay’s picture

There are two areas that need improvement:
* Patch application
* Determining what files were changed

We can improve patch application by doing a git apply --check or a patch -p1 --dry-run and seeing whether it will apply before actually trying it.

We can improve the determination of what files were changed rather dramatically by using git apply -v --check and parsing the result rather than doing what we're currently doing.

There is still some risk, particularly when just adding files, that this will make a mistake. But for the time being I think it's worth the risk. I'd like to phase out -p0 patches within the next year or so and then remove the code that handles this.

rfay’s picture

Title: Make git patch application more robust » Make git patch application more robust and use git for patch application

We definitely need to use git apply for actual application. See #22336: Move all core Drupal files under a /core folder to improve usability and upgrades.

Also, need to see what will happen with binary patches.

rfay’s picture

Priority: Normal » Critical
rfay’s picture

Here are the basics of what needs to happen with this patch:

1. Test patch application instead of just applying the patch.
2. Use git apply to apply the patch
3. Change to using the results of git apply --dry-run -v to determine what files are changed; much simpler.
4. Determine the consequences or implications of binary patches.

scor’s picture

Priority: Critical » Normal

subscribe. this should help to make the infrastructure more consistent, and once we figure out if #1116900: git format-patch displays file moves as whole verbose diffs is possible, make patches smaller :)

scor’s picture

Priority: Normal » Critical

oops

rfay’s picture

Assigned: Unassigned » rfay

I'm going to see if I can take a look at this tonight.

If it can be done and tested, it's easy to deploy because it just means deploying it on the testbots.

rfay’s picture

Status: Active » Needs review
FileSize
6.43 KB

I believe this is going to work. I'm testing it now, and will try it out on the scratch servers.

Status: Needs review » Needs work

The last submitted patch, pifr.apply_patches_with_git_1107552_08.patch, failed testing.

pillarsdotnet’s picture

+1

rfay’s picture

Status: Needs work » Fixed

I guess we'll have to fix the tests someday.

I committed this to 6.x-2.x: 5e8508

I tested it with binary patches and with moves. I also tested it with a number of -p0 and -p1 patches. It seems OK, although I wouldn't be surprised if there are a few patches that applied with patch that don't apply.

To create a binary patch: git format-patch --binary --full-index --stdout

To create a moves-and-copies patch (one that magically moves and copies): git format-patch -C -M --stdout

pillarsdotnet’s picture

Yay! (rfay++)

Question for rfay:

What do I need to put in my .gitconfig file so that the "--binary --full-index -C -C -M" options are the default?

I tried reading the git docs and couldn't figure it out. Or if there's a tutorial anywhere that you think answers the question, a link would be awesome.

For now I'm just using a bash alias...

rfay’s picture

Created 6.x-2.4 release containing this and requested deployment in #1122890: Deploy 6.x-2.4 of PIFR on qa.drupal.org

rfay’s picture

@pillarsdotnet, git help format-patch is the fastest way to the options. git help config is the fastest way to "how to set up .gitconfig".

It looks to me like git config --global diff.renames copy is what you want for automatic rename and copy detection.

I don't see instructions in there about using binary. I haven't experimented with it, but it may not be something you want on all the time. Seems relatively unusual that we want binary handling.

pillarsdotnet’s picture

Hmm.. maybe git config --global format.attach true allows binary?

Thanks anyway. I was hoping/expecting that "git config" could add any arbitrary command-line options, but I guess it can't. Back to bash aliases again.

chx’s picture

pillarsdotnet’s picture

chx++

Status: Fixed » Closed (fixed)

Automatically closed -- issue fixed for 2 weeks with no activity.