Git merge - to squash or not to squash?
[S]hould we merge feature/ticket branches back into their respective origins with the
--squashoption?
It all depends how fine-grained you want the history of your repo to be. Keep in mind that version control, via commit messages, is a form of code documentation. Squashing willy-nilly is certainly not good practice. It may be fine for a hotfix branch, but rarely is for a substantial feature branch.
As an analogy, imagine if you asked me for a lend of my Lost DVD boxset (i.e. you cloned my repo), and I just gave you the box, no DVDs, and told you
Here, just read the summary of the series on the backcover. That should tell you enough about the plot.
So, by all means, squash your commits when you want to get rid of intermediate steps that are needlessly detailed or not self-contained enough, but not to the point that it obscures the evolution of your repository.
(I discuss this matter further in this Twitter thread.)
Don’t squash: the small commits are useful especially for later tracking down of bugs with git bisect, and anyway you don’t want to change the history much. Just use a merge commit (git merge --no-ff) to keep the history organized.