# How to rewrite change with dependents

**URL:** <https://discourse.pijul.org/t/how-to-rewrite-change-with-dependents/1060>\
**Category:** Question\
**Created:** [June 5, 2023, 3:57am UTC](https://discourse.pijul.org/t/how-to-rewrite-change-with-dependents/1060 "2023-06-05T03:57:49Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Rosuavio](https://avatars.discourse-cdn.com/v4/letter/r/958977/32.png) [@Rosuavio](https://discourse.pijul.org/u/Rosuavio)\
**Post date:** [June 5, 2023, 3:57am UTC](https://discourse.pijul.org/t/how-to-rewrite-change-with-dependents/1060/1 "2023-06-05T03:57:49Z")

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I am having trouble finding a way to easily rewrite a change and reapply all of its dependents on top of the new change (like using `git rebase -i` to rewrite a non-HEAD commit in the history).

I know pijul works fundamentally differently than git, and this is not a common use case. But there are scenarios that I see myself needing to rewrite history (like removing secrets from a repo before publishing it to somewhere public).

I would like to rewrite a change that has dependent changes, while easily regenerating and applying dependent changes (I am expecting they would have new hashes). Also, flattening all the changes is not a suitable option for me.

I tried to store the changes of the dependents and then reapply them after applying the modified root change. But when I do this the dependent changes seem to reapply the original root change.

```auto
With original
A->B->C

# pijul change C > C.diff && pijul unrecord --reset C
# pijul change B > B.diff && pijul unrecord --reset B
A

# Make new changes...
# pijul record
A -> D

# pijul apply < C.diff
A -> D -> B -> C
Or probably something like
A -> D 
 \-> B -> C

Expecting
A -> D -> E
(Where E is C.diff applied on-top of D)

```

I really thought applying the output of `C.diff` would only apply the diff and not bring its dependencies along after reading

> You don’t need to worry about the `# Dependencies` block, it just needs to be there. The dependencies themselves will be re-computed by pijul when you record the change.

From [Splitting and combining changes - The Pijul manual](https://pijul.org/manual/workflows/splitting_and_combining_changes.html#splitting-a-change)

Also this might be related…

> [@Dependency Removal](https://discourse.pijul.org/t/dependency-removal/989):
>
> In Pijul, could it ever be possible to unrecord patches on which other patches inadvertently depend? Under a mental model where normal conflict resolution is completing a square by producing a combined O+A+B for a given O+A and O+B, for unrecording a dependency you could similarly provide an O+B for a given O+A and O+A+B.

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<div class="post-metadata">

**Author:** ![Rosuavio](https://avatars.discourse-cdn.com/v4/letter/r/958977/32.png) [@Rosuavio](https://discourse.pijul.org/u/Rosuavio)\
**Post date:** [June 6, 2023, 1:38am UTC](https://discourse.pijul.org/t/how-to-rewrite-change-with-dependents/1060/2 "2023-06-06T01:38:46Z")

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After some investigation it seems reusing a change on-top of different change then the original parent is very delicate, but possible.  
Given changes  
`A -> B - C`  
When I ran something like…

```auto
pijul change C > ".stash/C.diff" && pijul unrecord --reset C
pijul change B > ".stash/B.diff" && pijul unrecord --reset B

```

I was able to change `.stash/B.diff` in only a very minor way (in my testing changing a single character) and apply it `pijul apply < .stash/B.diff`. If I made such a minor change and then updated `C.diff` with the new change ID (from applying the modified `stash/B.diff`) in the place of the old one, then `C.diff` could be applied without an issue. Of course this would me that if any other subsequent changes would also need the change IDs of there dependencies updated too (more than okay in my case).

If I changed `B.diff` to add a different amount of characters, it seems to lead to a (seemingly) unnecessary conflict when trying to apply `C.diff`.

If I leave any old change IDs in `C.diff`s dependencies then they will get applied with the original C.diff.

I think using `pijul apply` on the output of a `pijul change` is maybe preserving much more than I am asking for. `pijul apply` seems to preserve the `message` `timestamp` `authors` `dependencies` and the `hunks`. If there was a way to preserve only the `message` and apply the `hunks` to the local tree and record the remaining changes for a new `change`. Then the `dependencies` could be recalculated, as well the `authors` and `timestamp`.

I have been trying to write a script to automate this, but I am falling short. Maybe if there was an easy way to apply the hunks in a change to the working tree.

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<div class="post-metadata">

**Author:** ![stellarpower](https://yyz1.discourse-cdn.com/flex031/user_avatar/discourse.pijul.org/stellarpower/32/489_2.png) [@stellarpower](https://discourse.pijul.org/u/stellarpower)\
**Post date:** [June 28, 2023, 11:45pm UTC](https://discourse.pijul.org/t/how-to-rewrite-change-with-dependents/1060/3 "2023-06-28T23:45:01Z")

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I feel the ability to edit changes after the fact more easily is probably an important requirement for me for r1. I get work is needed, but this is where the theory of pijul shines over other VCSs, so I reckon it’s really a selling point to have the implementation. In my case I’m wanting to split a change into smaller subchanges, and so I guess on this basis it should be possible to respect the dependencies. In fact maybe this solves the original question, as if the subchange representing the secrets can be separated from the other subchanges, then perhaps the changes that depend on it can be pulled out and then anything that depends on the secrets would need sorting before it could be dropped, or if it has no dependents then it can be safely removed.

Given changes consist of individual hunks, for a first pass would it at least be not too difficult in practice to separate out individual hunks into separate changes, which then would allow us potentially to edit one of those hunks?

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<div class="post-metadata">

**Author:** ![stellarpower](https://yyz1.discourse-cdn.com/flex031/user_avatar/discourse.pijul.org/stellarpower/32/489_2.png) [@stellarpower](https://discourse.pijul.org/u/stellarpower)\
**Post date:** [June 29, 2023, 12:40am UTC](https://discourse.pijul.org/t/how-to-rewrite-change-with-dependents/1060/4 "2023-06-29T00:40:10Z")

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Also, I guess this is slightly different, but at the minimum I think it should be possible to edit the change message, even if the change itself can’t be edited at the moment.