Git, diffs, and patches
I learned a few things when working on the key management patch that I
want to share here in case it helps anyone:
* git diff effectively creates a squashed diff of all commits/changes
* git format-patch wants to retain each commit (no squash)
* git format-patch has information about file name changes
(add/rename/remove) that git diff does not
* git apply and git am cannot process context diffs, only unified diffs
* git apply only applies changes to the files and therefore cannot
record file name changes in git, e.g., git add
* git am applies and merges changes, including file name changes
* to create a squashed format-patch, you have to create a new branch
and merge --squash your changed branch into that, then use git
format-patch
* to create a squashed git format-patch on top of a lower branch
you have to make a copy of the lower branch, merge --squash on the
upper branch on top of that, and then use git format-patch comparing
the lower branch to the upper one
Maybe everyone else knew these things, but I didn't. I can provide more
details if desired.
--
Bruce Momjian <bruce@momjian.us> https://momjian.us
EnterpriseDB https://enterprisedb.com
The usefulness of a cup is in its emptiness, Bruce Lee
On Fri, Jan 15, 2021 at 01:39:49PM -0500, Bruce Momjian wrote:
I learned a few things when working on the key management patch that I
want to share here in case it helps anyone:
...
Maybe everyone else knew these things, but I didn't. I can provide more
details if desired.
One more learning is that git diff compares two source trees and outputs
a diff, while format-patch compares two trees with a common commit and
outputs a diff for each commit. This is why format-patch can output
file name changes.
--
Bruce Momjian <bruce@momjian.us> https://momjian.us
EDB https://enterprisedb.com
The usefulness of a cup is in its emptiness, Bruce Lee