build problem with git worktree linked to main worktree (repo) (was: strange build problem with missing -by.el and -wy.el files)

[Gregor Zattler]

Hi Eli, emacs users,
* Eli Zaretskii <eliz@gnu.org> [2022-11-01; 18:48 +02]:
>> From: Gregor Zattler <telegraph@gmx.net>
>> Date: Tue, 01 Nov 2022 16:38:53 +0100
>>
>> > You need to understand why c-by.el is not generated as part of the
>> > build.  It's supposed to be generated by the rules in
>> > admin/grammars/Makefile.in, which run early on during the build.  It
>> > is run via the rule in lisp/Makefile.in for the target "semantic",
>> > look around line 415 in that file.  Why doesn't that happen in your
>> > case?
>>
>> Because I get "Args out of range: "master", 0, 7"
>> errors when building these files:
>
> So you need to understand why this happens.

I do not understand why this happens.

> Perhaps some stale files from previous builds, or some
> other problem?

This is from pristine sources.

But I found how to avoid it: Not using a git worktree linked
to a main worktree with .git directory:

The problem arises when the tree from which to build Emacs
is actually a linked git worktree as opposed to a fully
fletched git repo (main worktree in git parlance).

Building in a linked worktree linked to a bare repo works
without problems, though.

I described my findings in bug#59064.

I now will use git worktrees linked to a bare repo.

Thanks to Eli fro the hints, Gregor