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The git history command

lalitm.com

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Re: The git history command

#31
I don’t consider myself a coder or programmer, but learning git was like an organizational superpower for my particular brain wiring. I use it for websites, design projects, electronics engineering, music composition, personal knowledge bases, remote administration scripts, config management, snippets, so many applications and so many features for one system. It’s not always perfect, but I tell everyone I work with they should learn it.

Re: The git history command

#32
post #28

Earlier quoted context omitted.

Such as? When you merge a commit in that changed a file that has been already changed since the common ancestor, Git runs a tool of your choice on this file. If the tool fails, it marks the file as needing a merge and doesn't let you commit it until you unmark it to confirm that you have merged it manually. In case of octopus merges, it will just abort early. That's basically its whole behavior when it comes to confl…

Such as moving down a fixup during interactive rebase when it's going to conflict with parents, or I've added more commits mid-rebase, or the rebase started in a tool and now I need to think about the tool's command and understand how many times the rebase point is view is backwards to interpret which is "ours" and which is "theirs" and whether it's the tool, my editor, or my own experience I should ignore because it…

There's nothing "backwards" in "rebase point of view". It's just automated cherry-picking - it's like applying patches, it's as forwards as it gets. People who think it's "backwards" usually just have holes in their mental model of the repository. And yes, I find tools doing what you're asking them to do to be rather fine. In fact, Git makes it easy to notice when you're adding commits mid-rebase, which is something I often do intentionally, as it tells you what the HEAD is (and even shows a detailed state of the in-progress rebase) while authoring the commit message.

Re: The git history command

#33
post #17

> That last part goes further than git rebase --update-refs, which only moves refs sitting inside the range you’re actively rebasing. git history instead finds and rewrites every local branch descended from the commit (while also having an option to limit it to only the current branch). I'm reading that to mean that when I use `git rebase --update-refs` in this situation, where I've currently checked out `D` and upda…

> I'll end up with this state, where `E` remains untouched? Can't, because a commit's hash takes into account the parent hashes. Haven't used --update-refs, but reading it, it should result in your third graph. So, > is there a way to get `git rebase` to have the same behavior? is already the case.

> Haven't used --update-refs, but reading it, it should result in your third graph.

I don't think it does. I tried locally:

  mkdir test; cd test; git init
  touch a; git add a; git commit -m 'a'
  touch b; git add b; git commit -m 'b'
  touch c; git add c; git commit -m 'c'
  git checkout -b branched-feature HEAD~
  touch d; git add d; git commit -m 'd'
  git checkout main
  echo 'change' > b; git add b; git commit -m 'fix b'
  git rebase -i --root --update-refs
And ended up with this graph (`git log --graph --all`)

  * commit (HEAD -> main)
  |
  |     c
  |
  * commit 
  |
  |     b
  |
  | * commit (branched-feature)
  | |
  | |     d
  | |
  | * commit
  |/  
  |       b
  |
  * commit 
  
        a
Replacing the `git commit -m 'fix b'; git rebase -i --root --update-refs` with `git history fixup HEAD~` produces what I'd like:

  * commit (branched-feature)
  |
  |     d
  |
  | * commit (HEAD -> main)
  |/
  |       c
  |
  * commit
  |
  |     b
  |
  * commit 
  
        a

Re: The git history command

#34
post #25
post #6

> scary rebase -i commands that can leave your tree in a half-broken state if you so much as sneeze `git rebase --abort` exists. One can also set a tag or something before doing the rebase, do whatever, then `git reset --hard $set_tag` to go back. Nothing to be scared of. Not like the prior state is lost.

I have so many branches named `temp` or `before-rebase` for exactly that reason; I'm using them effectively as tags, but branches can be moved around with less ceremony than tags (since tags are designed to be for things like v1.2.3, placed once and then almost never moved again), so I usually just do `git branch before-rebase/some-feature` before running a big `rebase -i`. I've almost never needed to run `get reset…

> but branches can be moved around with less ceremony than tags

`git tag -f` to move a tag.

Personally, I just do `git show` when I'm feeling cautious, but I can generally just scroll up to find the last `git commit` I did with the hash in the output. `git reflog` should also have record of it, so everything else is kind of extra.

Re: The git history command

#35
post #17

Earlier quoted context omitted.

> I'll end up with this state, where `E` remains untouched? Can't, because a commit's hash takes into account the parent hashes. Haven't used --update-refs, but reading it, it should result in your third graph. So, > is there a way to get `git rebase` to have the same behavior? is already the case.

> Haven't used --update-refs, but reading it, it should result in your third graph. I don't think it does. I tried locally: mkdir test; cd test; git init touch a; git add a; git commit -m 'a' touch b; git add b; git commit -m 'b' touch c; git add c; git commit -m 'c' git checkout -b branched-feature HEAD~ touch d; git add d; git commit -m 'd' git checkout main echo 'change' > b; git add b; git commit -m 'fix b' git r…

Huh.. That's a shame :(. Maybe what it refers to is if you had a branch on B rather than D, it might update that.

EDIT: Yeah, this seems to be it. `git branch b` on b, then `git rebase -i --update-ref @~3` from main caused branch ref `b` to move from d86229e to 02fcaf7:

  * 1e354fb (HEAD -> main) fix b
  * 40e6f70 c
  * 02fcaf7 (b) b
  | * f4188e0 (branched-feature) d
  | * d86229e b
  |/  
  * 5fe78fa a

Re: The git history command

#36
post #12

I like to be like an accountant. No editing history. Create a new "journal entry" (i.e. commit) to fix.

Commit graph is just a data structure. Sometimes it represents a "history", sometimes other things. Personally, I like it when project's repository represents the history of the project rather than the history of random things developers do on their machines, but you do you.

[deleted]

Re: The git history command

#37
post #34
post #25

Earlier quoted context omitted.

I have so many branches named `temp` or `before-rebase` for exactly that reason; I'm using them effectively as tags, but branches can be moved around with less ceremony than tags (since tags are designed to be for things like v1.2.3, placed once and then almost never moved again), so I usually just do `git branch before-rebase/some-feature` before running a big `rebase -i`. I've almost never needed to run `get reset…

> but branches can be moved around with less ceremony than tags `git tag -f` to move a tag. Personally, I just do `git show` when I'm feeling cautious, but I can generally just scroll up to find the last `git commit` I did with the hash in the output. `git reflog` should also have record of it, so everything else is kind of extra.

Good point, that's no more ceremony than moving a branch. I guess I've just gotten "branches are movable tags" so deep into my hindbrain that I absorbed "tags are hard to move". But that's not actually true, and for what I'm doing (save this point in history for a while) a tag makes slightly more sense, semantically, than a branch.

Re: The git history command

#38
post #12

I like to be like an accountant. No editing history. Create a new "journal entry" (i.e. commit) to fix.

Commit graph is just a data structure. Sometimes it represents a "history", sometimes other things. Personally, I like it when project's repository represents the history of the project rather than the history of random things developers do on their machines, but you do you.

I am thinking of remote. Edits before pushing OK with me (they ate equivalent of recloning and redoing anyway)

Re: The git history command

#39
post #20
post #12

I like to be like an accountant. No editing history. Create a new "journal entry" (i.e. commit) to fix.

You probably shouldn’t be committing things that are broken…

Commit yes you absolutely can. Merge to trunk? Probably not, depends on your strategy.

Re: The git history command

#40
post #28

Earlier quoted context omitted.

Such as? When you merge a commit in that changed a file that has been already changed since the common ancestor, Git runs a tool of your choice on this file. If the tool fails, it marks the file as needing a merge and doesn't let you commit it until you unmark it to confirm that you have merged it manually. In case of octopus merges, it will just abort early. That's basically its whole behavior when it comes to confl…

Such as moving down a fixup during interactive rebase when it's going to conflict with parents, or I've added more commits mid-rebase, or the rebase started in a tool and now I need to think about the tool's command and understand how many times the rebase point is view is backwards to interpret which is "ours" and which is "theirs" and whether it's the tool, my editor, or my own experience I should ignore because it…

> which is "ours" and which is "theirs"

"ours" is always HEAD, usually meaning the state of the working_tree, "theirs" is always the commit that is going to change the working_tree.

When merging, you are taking change from another branch (theirs) to create a new commit on the current branch (ours) that ties the two together. When rebasing interactively, you switch to the new base (ours) and replay the changes of the branch (theirs) according to the edit file.

Etymology matters. The conceptual model of git is simple, but people only focus on the operations. That's like trying to learn algorithm and data structures and focusing on the words "insert", "remove", "find", without trying to learn "list", "stack", "tree",... first.

Instead learn about Git's glossary [0], then how the operations use and modify those concepts.

[0] https://git-scm.com/docs/gitglossary

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