Not rebasing does not affect reviewing a branch in the least, unless your diff software is seriously broken.
Comparing a branch to trunk shoudl only shows the actual difference. That you merged trunk multiple times shoudl have zero bearing.
The only way it could ever confuse anyone is if they review every commit and somehow fail to pass over merge commits.
The single most aggravating thing in git are its self-appointed super-users who /almost always/ properly use its power until one day they don't. Then they make life miserable for everyone else while we all "just wait, I'm fixing it".
Feature branches really should be rebased to have clean self-contained logical commits prior to merging, and this goes beyond just making it easier to review (although that is an important point). It's good git hygiene!
No individual commit should break the build; one reason is to keep git-bisect working well for future users bug-hunting, without getting stopped because someone didn't keep the commits on their dev branch clean prior to merging (N.B., a maintainer should also reject such PRs). And keeping commits clean usually means needing to rebase occasionally to organize the commits.
And each commit should be reviewed individually, in addition to the whole of the branch / PR.
Not to mention that each commit should be logically laid out, with well-defined changes and well-written commit messages. This usually means needing to rebase a branch when developing non-trivial features or bug fixes, to fold in review feedback.
But as mentioned elsewhere, generally on feature / dev branches, the expectation is that the commits are unstable, subject to change, and should not be built upon (without prior coordination, at least).
Master and stable release branches, on the other hand, should never change or be rebased.
Absolutely. Personally, I like to spam commits while I'm developing, just to make sure I keep track of what I've done while I'm iterating, but none of this is relevant to the final merge. Any individual commit on my feature branch may not even compile, but when that feature is applied to master, I want it to be a clean atomic commit that can easily be reverted or applied to other branches.
1. I didn't say this affects branch diffing, but rather trawling through history on a single branch.
2. "self-appointed super-users [...] [who break everything]" is a strawman and borderline ad-hominem. If you follow the guidelines I put forth, there won't be any issues collaborating with others.
Also, as a general note, it's actually very difficult to completely destroy information that's been committed at some point. If you're really running into issues with this, don't let fear direct you away from enjoying the greatest features of git. Experiment! Keep trying. Read a good git book (https://git-scm.com/book/en/v2). And learn to use the reflog. Everything you've committed is backed up for a long time even if you've removed all named references to those commits.
> I didn't say this affects branch diffing, but rather trawling through history on a single branch.
Exactly. What's the point of all the "oops, a typo" or "applying code review remarks, part III" commits. Just rewrite. This is the workflow you get eg. with Gerrit.
Comparing a branch to trunk shoudl only shows the actual difference. That you merged trunk multiple times shoudl have zero bearing.
The only way it could ever confuse anyone is if they review every commit and somehow fail to pass over merge commits.
The single most aggravating thing in git are its self-appointed super-users who /almost always/ properly use its power until one day they don't. Then they make life miserable for everyone else while we all "just wait, I'm fixing it".