bug#38867: 27.0.60; fileloop-initialize-replace misses occurrences to be replaced

[Eric Michael Timmons]

Severity: normal
Tags: patch

When using fileloop-initialize-replace on files that already have open
buffers and points in arbitrary locations, occurrences of the regex to
replace can be missed. This appears to happen on my setup when
switch-to-buffer-preserve-window-point is non-nil. The call to
switch-buffer between the invocation of the scan- and operate-functions
can then cause the point to change to a different location than the
scan-function left it.

This can manifest itself by either missing occurrences of the regex in
the open files where point is beyond some occurrences or it can
completely miss files if some file early on in the iteration has its
point beyond all occurrences of the regex, causing the operate-function
to return nil, aborting the rest of the operation.

In GNU Emacs 27.0.60 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.13, cairo 
version 1.16.0)
 of 2019-12-27 built on rocinante
Repository revision: 8224ed7d406e8654a163b05c0c647a5d44c090ed
Repository branch: emacs-27
Windowing system distributor 'The X.Org Foundation', version 11.0.12006000
System Description: Gentoo/Linux

0001-Fix-fileloop-initialize-replace-with-buffers-that-ar.patch
Description: 0001-Fix-fileloop-initialize-replace-with-buffers-that-ar.patch