Implement rebase --skip-empty #2609
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
PhilipMetzger
requested changes
Nov 21, 2023
There was a problem hiding this comment.
Hi, thanks for implementing your feature request.
I left a bunch of comments and I want to remind you that we prefer a linear history in this project, so you'll need to squash this into two or three commits. See https://github.com/martinvonz/jj/blob/main/docs/contributing.md#code-reviews
martinvonz
reviewed
Nov 22, 2023
matts1
force-pushed
the
skip-empty
branch
2 times, most recently
from
dd50d9a to
85ff2f0
Compare
yuja
reviewed
Nov 22, 2023
PhilipMetzger
approved these changes
Nov 22, 2023
ilyagr
added a commit
to ilyagr/jj
that referenced
this pull request
Nov 26, 2023
This follows up on @matts1 's jj-vcs#2609. We still allow the `-r` commit to become empty. I would be more comfortable if there was a test for that, but I haven't done that (yet?) and it seems pretty safe. If that's a problem, I'm happy to forbid `-r --skip-empty` entirely, since it is far less useful than `-s --skip-empty` or `-b --skip-empty`. I think it is reasonable not to empty descendants, since as far as descendants of `A` are concerned, `jj rebase -r A` should be equivalent to `jj abandon A`, and `jj abandon` does not empty anything. Moreover, if we did want -r to empty descendants of `A`, we'd have to improve the algorithm and add thorough tests. For example, if we have root -> A -> B -> C and `jj rebase -r A -d C` empties commit `B` (or `C`), I do not believe the current algorithm will work correctly.
ilyagr
added a commit
to ilyagr/jj
that referenced
this pull request
Nov 26, 2023
This follows up on @matts1 's jj-vcs#2609. We still allow the `-r` commit to become empty. I would be more comfortable if there was a test for that, but I haven't done that (yet?) and it seems pretty safe. If that's a problem, I'm happy to forbid `-r --skip-empty` entirely, since it is far less useful than `-s --skip-empty` or `-b --skip-empty`. I think it is reasonable not to empty descendants, since as far as descendants of `A` are concerned, `jj rebase -r A` should be equivalent to `jj abandon A`, and `jj abandon` does not empty anything. Moreover, if we did want -r to empty descendants of `A`, we'd have to improve the algorithm and add thorough tests. For example, if we have ``` root -> A -> B -> C ``` and `jj rebase -r A -d C` empties commit `B` (or `C`), I do not believe the current algorithm will work correctly.
ilyagr
added a commit
to ilyagr/jj
that referenced
this pull request
Nov 26, 2023
This follows up on @matts1 's jj-vcs#2609. We still allow the `-r` commit to become empty. I would be more comfortable if there was a test for that, but I haven't done that (yet?) and it seems pretty safe. If that's a problem, I'm happy to forbid `-r --skip-empty` entirely, since it is far less useful than `-s --skip-empty` or `-b --skip-empty`. I think it is reasonable not to empty descendants, since as far as descendants of `A` are concerned, `jj rebase -r A` should be equivalent to `jj abandon A`, and `jj abandon` does not remove emptid commits. It also doesn't seem very useful to do that to descendant commits. Moreover, if we did want -r to empty descendants of `A`, we'd have to improve the algorithm and add thorough tests. For example, if we have ``` root -> A -> B -> C ``` and `jj rebase -r A -d C` empties commit `B` (or `C`), I do not know whether the current algorithm will work correctly. It seems possible that it would, but that depends on the fact that empty merge commits are not abandoned. That seems dangerous to rely on without tests.
ilyagr
added a commit
to ilyagr/jj
that referenced
this pull request
Nov 26, 2023
This follows up on @matts1 's jj-vcs#2609. We still allow the `-r` commit to become empty. I would be more comfortable if there was a test for that, but I haven't done that (yet?) and it seems pretty safe. If that's a problem, I'm happy to forbid `-r --skip-empty` entirely, since it is far less useful than `-s --skip-empty` or `-b --skip-empty`. I think it is undesired to abandon emptied descendants, since as far as descendants of `A` are concerned, `jj rebase -r A` should be equivalent to `jj abandon A`, and `jj abandon` does not remove emptied commits. It also doesn't seem very useful to do that to descendant commits, since I think they'd only become empty in pathological cases. Additionally, if we did want -r to empty descendants of `A`, we'd have to add thorough tests and possibly improve the algorithm. I want to refactor `rebase -r` and add features to it, and considering these cases makes everything harder. For example, if we have ``` root -> A -> B -> C ``` and `jj rebase -r A -d C` empties commit `B` (or `C`), I do not know whether the current algorithm will work correctly. It seems possible that it would, but that depends on the fact that empty merge commits are not abandoned. That seems dangerous to rely on without tests.
ilyagr
added a commit
to ilyagr/jj
that referenced
this pull request
Nov 26, 2023
This follows up on @matts1 's jj-vcs#2609. We still allow the `-r` commit to become empty. I would be more comfortable if there was a test for that, but I haven't done that (yet?) and it seems pretty safe. If that's a problem, I'm happy to forbid `-r --skip-empty` entirely, since it is far less useful than `-s --skip-empty` or `-b --skip-empty`. I think it is undesired to abandon emptied descendants, since as far as descendants of `A` are concerned, `jj rebase -r A` should be equivalent to `jj abandon A`, and `jj abandon` does not remove emptied commits. It also doesn't seem very useful to do that to descendant commits, since I think they'd only become empty in pathological cases. Additionally, if we did want -r to empty descendants of `A`, we'd have to add thorough tests and possibly improve the algorithm. I want to refactor `rebase -r` and add features to it, and considering these cases makes everything harder. For example, if we have ``` root -> A -> B -> C ``` and `jj rebase -r A -d C` empties commit `B` (or `C`), I do not know whether the current algorithm will work correctly. It seems possible that it would, but that depends on the fact that empty merge commits are not abandoned for descendants. That seems dangerous to rely on without tests. Making DescendantRebaser return more information (which I am likely to do as part of implementing `-r --after`) should help make such code more obviously correct.
ilyagr
added a commit
to ilyagr/jj
that referenced
this pull request
Nov 26, 2023
This follows up on @matts1 's jj-vcs#2609. We still allow the `-r` commit to become empty. I would be more comfortable if there was a test for that, but I haven't done that (yet?) and it seems pretty safe. If that's a problem, I'm happy to forbid `-r --skip-empty` entirely, since it is far less useful than `-s --skip-empty` or `-b --skip-empty`. I think it is undesired to abandon emptied descendants. As far as descendants of `A` are concerned, `jj rebase -r A` should be equivalent to `jj abandon A`, and `jj abandon` does not remove emptied commits. It also doesn't seem very useful to do that, since I think descendant commits of an abandoned (or moved with `-r`) commit only become empty in pathological cases. Additionally, if we did want -r to empty descendants of `A`, we'd have to add thorough tests and possibly improve the algorithm. I want to refactor `rebase -r` and add features to it, and having to consider cases of commits becoming abandoned makes everything harder. For example, if we have ``` root -> A -> B -> C ``` and `jj rebase -r A -d C` empties commit `B` (or `C`), I do not know whether the current algorithm will work correctly. It seems possible that it would, but that depends on the fact that empty merge commits are not abandoned for descendants. That seems dangerous to rely on without tests. I hope (but can't promise) that in the near future, making DescendantRebaser return more information should help make it possible to create such functionality in a more robust way. I am likely to attempt this as part of implementing `-r --after`.
ilyagr
added a commit
to ilyagr/jj
that referenced
this pull request
Nov 26, 2023
This follows up on @matts1 's jj-vcs#2609. We still allow the `-r` commit to become empty. I would be more comfortable if there was a test for that, but I haven't done that (yet?) and it seems pretty safe. If that's a problem, I'm happy to forbid `-r --skip-empty` entirely, since it is far less useful than `-s --skip-empty` or `-b --skip-empty`. I think it is undesired to abandon emptied descendants. As far as descendants of `A` are concerned, `jj rebase -r A` should be equivalent to `jj abandon A`, and `jj abandon` does not remove emptied commits. It also doesn't seem very useful to do that, since I think descendant commits of an abandoned (or moved with `-r`) commit only become empty in pathological cases. Additionally, if we did want -r to empty descendants of `A`, we'd have to add thorough tests and possibly improve the algorithm. I want to refactor `rebase -r` and add features to it, and having to consider cases of commits becoming abandoned makes everything harder. For example, if we have ``` root -> A -> B -> C ``` and `jj rebase -r A -d C` empties commit `B` (or `C`), I do not know whether the current algorithm will work correctly. It seems possible that it would, but that depends on the fact that empty merge commits are not abandoned for descendants. That seems dangerous to rely on without tests. I hope (but can't promise) that in the near future, making DescendantRebaser return more information should help make it possible to create such functionality in a more robust way. I am likely to attempt this as part of implementing `-r --after`.
ilyagr
added a commit
to ilyagr/jj
that referenced
this pull request
Nov 26, 2023
This follows up on @matts1 's jj-vcs#2609. We still allow the `-r` commit to become empty. I would be more comfortable if there was a test for that, but I haven't done that (yet?) and it seems pretty safe. If that's a problem, I'm happy to forbid `-r --skip-empty` entirely, since it is far less useful than `-s --skip-empty` or `-b --skip-empty`. I think it is undesired to abandon emptied descendants. As far as descendants of `A` are concerned, `jj rebase -r A` should be equivalent to `jj abandon A`, and `jj abandon` does not remove emptied commits. It also doesn't seem very useful to do that, since I think descendant commits of an abandoned (or moved with `-r`) commit only become empty in pathological cases. Additionally, if we did want -r to empty descendants of `A`, we'd have to add thorough tests and possibly improve the algorithm. I want to refactor `rebase -r` and add features to it, and having to consider cases of commits becoming abandoned makes everything harder. For example, if we have ``` root -> A -> B -> C ``` and `jj rebase -r A -d C` empties commit `B` (or `C`), I do not know whether the current algorithm will work correctly. It seems possible that it would, but that depends on the fact that empty merge commits are not abandoned for descendants. That seems dangerous to rely on without tests. I hope (but can't promise) that in the near future, making DescendantRebaser return more information should help make it possible to create such functionality in a more robust way. I am likely to attempt this as part of implementing `-r --after`.
ilyagr
added a commit
that referenced
this pull request
Nov 26, 2023
This follows up on @matts1 's #2609. We still allow the `-r` commit to become empty. I would be more comfortable if there was a test for that, but I haven't done that (yet?) and it seems pretty safe. If that's a problem, I'm happy to forbid `-r --skip-empty` entirely, since it is far less useful than `-s --skip-empty` or `-b --skip-empty`. I think it is undesired to abandon emptied descendants. As far as descendants of `A` are concerned, `jj rebase -r A` should be equivalent to `jj abandon A`, and `jj abandon` does not remove emptied commits. It also doesn't seem very useful to do that, since I think descendant commits of an abandoned (or moved with `-r`) commit only become empty in pathological cases. Additionally, if we did want -r to empty descendants of `A`, we'd have to add thorough tests and possibly improve the algorithm. I want to refactor `rebase -r` and add features to it, and having to consider cases of commits becoming abandoned makes everything harder. For example, if we have ``` root -> A -> B -> C ``` and `jj rebase -r A -d C` empties commit `B` (or `C`), I do not know whether the current algorithm will work correctly. It seems possible that it would, but that depends on the fact that empty merge commits are not abandoned for descendants. That seems dangerous to rely on without tests. I hope (but can't promise) that in the near future, making DescendantRebaser return more information should help make it possible to create such functionality in a more robust way. I am likely to attempt this as part of implementing `-r --after`.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Fixes issue #229. See the issue for discussions.
Checklist
If applicable:
CHANGELOG.md