change PIDFile default from /var/run/gitea.pid to /run/gitea.pid

[flokli]

On most modern distributions, /var/run is deprecated and only kept for backwards compat according to
https://refspecs.linuxfoundation.org/FHS_3.0/fhs/ch05s13.html, and is a symlink to /run/ on modern distributions.

Old Distros that still don't have /run can update the gitea default as described in from-source.en-us.md to point to the old location.

Follow-up on #12391 (comment) and #12485.

[6543]

lable: kind/breaking

do we realy have to change this default?

[codecov-commenter]

Codecov Report

Merging #12500 into master will increase coverage by 0.03%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master   #12500      +/-   ##
==========================================
+ Coverage   43.49%   43.53%   +0.03%     
==========================================
  Files         642      642              
  Lines       71003    71003              
==========================================
+ Hits        30886    30910      +24     
+ Misses      35108    35092      -16     
+ Partials     5009     5001       -8     

Impacted Files	Coverage Δ
modules/setting/setting.go	45.80% <ø> (ø)
modules/queue/workerpool.go	58.77% <0.00%> (-1.23%)	⬇️
services/pull/pull.go	42.03% <0.00%> (+0.46%)	⬆️
models/error.go	35.66% <0.00%> (+0.85%)	⬆️
models/notification.go	67.04% <0.00%> (+0.91%)	⬆️
modules/log/event.go	57.54% <0.00%> (+0.94%)	⬆️
modules/queue/unique_queue_disk_channel.go	55.38% <0.00%> (+1.53%)	⬆️
modules/notification/ui/ui.go	83.33% <0.00%> (+2.77%)	⬆️
services/pull/check.go	50.76% <0.00%> (+3.07%)	⬆️
modules/notification/mail/mail.go	36.25% <0.00%> (+3.75%)	⬆️
... and 1 more

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[flokli]

do we realy have to change this default?

I'm not sure why gitea would need to still point to a long-deprecated location (and if so, for how long?)
The burden of using outdated paths should really be on those outdated distros, not applications.

Most userspace tools have defaulted to use /run these days (so packagers of such distros are used to having to change this).

Gitea provides a documented way to change the default, and it would be part of the release notes, too.

[silverwind]

Kind of unrelated, but I question if we even need to have a PID file in the default configuration. Service managers like systemd can do without one and by not having one, we can eliminate a whole class of potential errors related to stale pid files.

[zeripath]

@silverwind We don't create a pid file by default - it is only if the user requests one.

[silverwind]

Is that an undocumented option? I can't find anything related to pid files in app.example.ini or the cheat sheet docs.

[zeripath]

That's because it's not an app.ini option. It's a command line option:

https://docs.gitea.io/en-us/command-line/#web