Re: Removing unneeded self joins

On Sat, Feb 24, 2024 at 12:36:59AM +0200, Alexander Korotkov wrote:
> On Thu, Feb 22, 2024 at 10:51 AM Andrei Lepikhov <a(dot)lepikhov(at)postgrespro(dot)ru> wrote:
> > On 21/2/2024 14:26, Richard Guo wrote:
> > > I think the right fix for these issues is to introduce a new element
> > > 'sublevels_up' in ReplaceVarnoContext, and enhance replace_varno_walker
> > > to 1) recurse into subselects with sublevels_up increased, and 2)
> > > perform the replacement only when varlevelsup is equal to sublevels_up.
> > This code looks good. No idea how we have lost it before.
>
> Thanks to Richard for the patch and to Andrei for review. I also find
> code looking good. Pushed with minor edits from me.

I feel this, commit 466979e, misses a few of our project standards:

- The patch makes many non-whitespace changes to existing test queries. This
makes it hard to review the consequences of the non-test part of the patch.
Did you minimize such edits? Of course, not every such edit is avoidable.

- The commit message doesn't convey whether this is refactoring or is a bug
fix. This makes it hard to write release notes, among other things. From
this mailing list thread, it gather it's a bug fix in 489072ab7a, hence
v17-specific. The commit message for 489072ab7a is also silent about that
commit's status as refactoring or as a bug fix.

- Normally, I could answer the previous question by reading the test case
diffs. However, in addition to the first point about non-whitespace
changes, the first three join.sql patch hunks just change whitespace.
Worse, since they move line breaks, "git diff -w" doesn't filter them out.

To what extent are those community standards vs. points of individual
committer preference? Please tell me where I'm wrong here.