Show blame information for a line from the *magit* buffer

Question

There's a workflow I tend to do fairly often and I wonder if Magit could help me. I've made a bunch of git commits on a branch, I haven't pushed them yet, and I notice a small mistake in my unpushed work which I'd like to fix by amending the commit that introduced it rather than making a new commit.

I can use blame to find the offending commit, do an interactive rebase and edit the offending commit. But that's not always convenient. For example, if I run a validation process and find multiple minor issues, then I need to fix multiple commits. What I do is to make all the fixes, commit them separately, and then do an interactive rebase to apply them as fixups. (For the sake of this question, assume that this won't lead to a conflict.) So my workflow is, for each fix:

1. Stage the fix.
2. Use blame to locate the commit that needs to be amended. I do this from vc-annotate, because it shows me the commit ID for each line in a very handy way.

3. Commit the fix with the message fixup 1234567 where 1234567 is the commit ID.

4. Then I do an interactive rebase to apply the fixup NNNNNNN as fixups to their respective NNNNNNN.

Can Magit help me with step 2? I'm in the *magit* buffer, looking at a deleted or unchanged line, and I want the blame information for that line, i.e. the commit ID that introduced that line.

modified   myfile
@@ -1,3 +1,3
 foo
-bat               ←My cursor is here. What commit introduced `bat`?
+bar
 qux

Answer 1

Since I have started using git autofixup I have saved a lot of time determining "the commit where I should have done that in the first place".

Magit wraps that as magit-commit-absorb, but this command isn't available from the committing popup by default yet.

Here's a typical workflow.

1. Do not stage your changes. (git autofixup operates on all unstaged changes and refuses to do anything if there are staged changes. I think it should instead operate on the staged changes and ignore the unstaged ones. Maybe in a future version.)

2. Type c x. (After having added that binding for magit-commit-absorb.)

3. Briefly look at the generated fixup commits.

4. r f to join the fixup commits with their targets.