#3658 PR `open`: Use extglob instead of brace expansion in FILES_TO_PATCH_PATTERNS¶

Labels: enhancement, minor bug, ready-to-merge?

svlv opened issue at 2026-10-29 11:23:¶

Type: Bug Fix
Impact: Normal
Reference to related issue (URL):
How was this pull request tested?
Verified that files.md5sum contains hash for /boot/grub2/grub.cfg
Description of the changes in this pull request:

Bash does not perform brace expansion on variable values, so the {...} lists in FILES_TO_PATCH_PATTERNS were passed to pathname expansion literally, matched nothing, and were dropped by nullglob. As a result the GRUB files (grub.conf, grub.cfg, menu.lst, device.map) were excluded from checksum generation and from UUID and device name migration. The bug introduced by 7f61a4f4283e403ba3e44db9ee6bd52bd45d9519.

Reproduce in a terminal:
```
$ mkdir -p boot/grub2
$ touch boot/grub2/grub.cnf
$ shopt -s nullglob

$ for file in [b]oot/grub2/{grub.cnf,grub.conf} ; do echo "$file" ; done
boot/grub2/grub.cnf <=== expected output, since boot/grub2/grub.cnf exists

$ GLOB="[b]oot/grub2/{grub.cnf,grub.conf}" ; for file in $GLOB ; do echo "$file" ; done
                  <=== nothing, which is unexpected and indicates the issue
```
Replace brace expansion in FILE_TO_PATCH_PATTERNS with Bash extended globbing, which is implicitly enabled in ReaR.

codacy-production commented at 2026-10-29 11:25:¶

Up to standards ✅¶

🟢 Issues 0 issues

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pcahyna commented at 2026-10-30 10:42:¶

The bug introduced by https://github.com/rear/rear/commit/7f61a4f4283e403ba3e44db9ee6bd52bd45d9519.

Oops :-( thank you for spotting it. Will have a look.

jsmeix commented at 2026-11-02 14:55:¶

It works
(at least for me with GNU bash, version 5.2.37)
but I fail to understand why.

When reading "man bash" which reads

    @(pattern-list)
        Matches one of the given patterns

I falsely thought that e.g.

@(grub.conf|grub.cfg|grubenv|menu.lst|device.map)

would match only one of the listed patterns.

But actually it matches all that exist:

# ls /boot/grub2
fonts  grub.cfg  grubenv  locale  themes  x86_64-efi

# ( shopt -s nullglob extglob ; \
  for f in /[b]oot/grub2/{grub.conf,grub.cfg,grubenv,menu.lst,device.map} ; \
  do echo "$f" ; done )
/boot/grub2/grub.cfg
/boot/grub2/grubenv

# ( shopt -s nullglob extglob ; \
  g="/[b]oot/grub2/{grub.conf,grub.cfg,grubenv,menu.lst,device.map}" ; \
  for f in $g ; do echo "$f" ; done )

# ( shopt -s nullglob extglob ; \
  g="/[b]oot/grub2/@(grub.conf|grub.cfg|grubenv|menu.lst|device.map)" ; \
  for f in $g ; do echo "$f" ; done )
/boot/grub2/grub.cfg
/boot/grub2/grubenv

Can one explain how that works?

svlv commented at 2026-11-02 15:07:¶

It's better to think about it keeping the following in the head:

@( … ) | Only one occurrence
*( … ) | Zero or more occurrences
+( … ) | One or more occurrences
?( … ) | Zero or one occurrences
!( … ) | Not these occurrences, but anything else

@(a|b).jpeg will match a.jpeg or b.jpeg but not aa.jpeg or bb.jpeg. I think this short explanation will be enough

gdha commented at 2026-11-05 13:30:¶

@rear/contributors if there are no objection would like to merge this PR around Nov.11th

[Export of Github issue for rear/rear.]

#3658 PR open: Use extglob instead of brace expansion in FILES_TO_PATCH_PATTERNS¶