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by aidenn0 2086 days ago
Contrary to that article, squashing aids bisection rather than hurts it.

One simple example:

commit 1: things work

commit 2: Feature X, regress

commit 4: Feature Y, break things by accident

commit 5: oops, fix commit #4

...

You land on commit 4 breaking your commit, but if #5 and #4 had been squashed then you would find commit #3 much more easily.

With a tiny history like this it's not a big deal, but with a larger one, it becomes an issue.
2 comments
progval 2086 days ago
On personal projects (using git), I use squashing only for small bug fixes like the one you mentioned or when the author of a PR made a big mess of commits (usually because they are a git beginner). Best of both worlds.
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aidenn0 2086 days ago
Do you not make a big mess of commits, then selectively squash before submitting a PR?
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wyoung2 2086 days ago
I don't see why you would bisect in this situation in the first place. The problem's fixed now, as of commit 5.

But okay, let's take your example as-is: you determine the "good" point is commit 1, and the ...um, other good point is commit 5?

Well, that doesn't work. I guess we have to arbitrarily ignore commit 5 and say commit 4 is bad. A bisect will show that. Then in Fossil, if you visit the /info page for commit 4, it will show its child commit 5 as fixing the problem.

Try again. Squashing doesn't solve anything here.

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aidenn0 2085 days ago
I'm rebasing because the problem from commit #2 isn't fixed. We have a test that shows the problem from commit #2. However commit #4 breaks things in some way that the test we are running can't run. Squashing the commits together fixes this. If commits #4 and #5 were both on a feature branch before merging, squashing would be done by rebasing in the feature branch.

I'm not saying all commits from a feature branch should be squashed to a single commit, but commits like "oops forgot to update header file" or some such are noise.

Rewriting history is about improving the signal-to-noise ratio. You may lose some signal (the Fossil argument against it), but if you lose more noise than signal it may be worth it (the git argument for it).

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