Re: [PATCH] Remove unused #include's in src/backend/commands/*

Hi Nathan,

> Seems reasonable to me. Most of these seem to be recent additions since
> last year's round of IWYU commits. Any reason to limit this to
> src/backend/commands? Why not tackle the whole tree at once?

The main problem here is that clangd is a language server, which means
I see errors reported by it when I open a particular file in a text
editor. To go manually over ~2500 .c/.h files we have and then see
what will break on CI because of an #ifdef (as it was with the patch
v1) doesn't strike me as a great idea :)

In theory there is a way to get clangd warnings for a given file using
a command like this:

# use meson; make sure build/compile_commands.json exists
path/to/bin/clangd --enable-config \
--log=error \
--compile-commands-dir=build \
--check="src/backend/commands/collationcmds.c"

... which can be executed in a loop for all the existing files.
Unfortunately it doesn't work. The command outputs multiple errors,
something about:

```
FAIL: The new replacement overlaps with an existing replacement.
```

¯\_(ツ)_/¯ So far I haven't figured out how to make it work.

Alternatively we could prioritize ~100 .c files which can be checked
manually. Or we can make changes iteratively, as with patches v1/v2.

Personally I prefer multiple small changes to a single but huge one to
be honest.

--
Best regards,
Aleksander Alekseev