[cerved]

Don't squash. If you insist on it, I can't imagine why you wouldn't squash the commit messages

You're not supposed to change commit messages.

The correct lines to blame are the ones right there, not exactly rocket science

[josephg]

If your git squash contains all the commit messages, it’s a pain to figure out which commit message refers to which line of code.

A comment goes right there. No tools needed. Mutable. Readable. Contextually in place. And you can even add comments while coding without waiting for the commit.

Is typing // really so much effort?

[cerved]

No it's not and neither is writing a proper commit message. That's why you do both, but most of it goes in the commit. Like in the Git project