[DRE-maint] Bug#1122890: gem2deb: issue with version and syntax of file debian/watch

[Norwid Behrnd]

Package: gem2deb
Version: 2.2.6
Severity: normal
X-Debbugs-Cc: nbehrnd at yahoo.com

Dear Maintainer,

*** Reporter, please consider answering these questions, where appropriate ***

While updating ruby-mdl/markdownlint, I noticed current gem2deb creates a watch
file which is in sync with watch [documentation] (last modified 2025-08-31
19:44:00), i.e.

```
version=4
https://gemwatch.debian.net/mdl .*/mdl-(.*).tar.gz

# Use the regex below for github-based sources
# opts=uversionmangle=s/[_.+-]?(rc|pre|dev|beta|alpha|b|a)/~$1/i,\
# filenamemangle=s%(?:.+/)?v?@ANY_VERSION@(@ARCHIVE_EXT@)%@PACKAGE at -$1$2% \
#   https://github.com/<owner>/<repo>/tags .*/v?@ANY_VERSION@@ARCHIVE_EXT@
```

which so far was functional, too.  However, by the command of

```bash
uscan --update-watchfile
```

(with uscan version 2.25.28) the file is overwritten, incremented by one and of
slightly different syntax:

```
Version: 5

Source: https://gemwatch.debian.net/mdl
Matching-Pattern: .*/mdl-(.*).tar.gz
```

I interpret the reports by `lintian` of a newly assembled .deb, as well as by
running

```bash
uscan --no-download --verbose --debug
```

with either version of the watch file as if the newer version 5 were preferred.

My question: if version 5 is new standard to adhere to, will future versions of
`gem2deb` write the watch file right in this pattern?


-- System Information:
Debian Release: forky/sid
  APT prefers testing
  APT policy: (500, 'testing'), (500, 'stable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 6.9.10-amd64 (SMP w/4 CPU threads; PREEMPT)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages gem2deb depends on:
ii  debhelper [debhelper-compat]  13.28
ii  gem2deb-test-runner           2.2.6
ii  perl                          5.40.1-7
ii  rake                          13.2.1-1
ii  ruby                          1:3.3+b1
ii  ruby-all-dev                  1:3.3+b1

Versions of packages gem2deb recommends:
ii  apt-file         3.3
ii  build-essential  12.12
ii  debian-policy    4.7.2.0
ii  devscripts       2.25.28
ii  python3-debian   1.0.1

Versions of packages gem2deb suggests:
ii  git-buildpackage  0.9.39
ii  pristine-tar      1.50+nmu2

-- no debconf information