Sometime theme chooser downloads trunk themes instead of correct version

[Peter Bennett]

See this thread
​https://lists.gt.net/mythtv/users/607576#607576
In the build that this user has, the mythtv versions are as follows

MythTV Version : 3543e74
MythTV Branch : tag: v0.28

We need to fix the build to have correct version and fix the theme selector to select correct theme versions.

[Peter Bennett]

The user says

I am using the official ArchLinux packages. However mythfrontend version says:

 MythTV Version : 3543e74
 MythTV Branch : tag: v0.28
 Network Protocol : 88
 Library API : 0.28.20160309-1
 QT Version : 5.7.0

If I check out a tag name I get

MythTV Version : v0.28
MythTV Branch : (HEAD detached at v0.28)

I do not understand what type of build results in the MythTV version being the commit hash and the branch being a string like "tag: v0.28". I tried creating a branch with name "tag: v0.28" and the name was invalid, so that is not what they did. Perhaps I should force the build to fail on an invalid Version (i.e. not starting with v).

[Jonatan Lindblad]

It seems to happen when you download the source from GitHub, for example ​https://github.com/MythTV/mythtv/archive/v0.28.tar.gz.

[Peter Bennett]

Thank you Jonatan. That is it.

I am changing the compile to construct a valid version in that case, using the tag in the branch, and where that is not present, the VERSION file in the source, and appending the hash. The version will be formatted similar to below examples, whether you export from a tag, master or a branch:

v29-30d8a96 or v29-Pre-30d8a96 or v29.1-30d8a96

It is not quite the same as the git describe used when building from a checkout, but is a lot better than just the plain hash, and will work with theme download.

[Peter Bennett]

Proposed fix

[Peter Bennett <pbennett@…>]

In 7723e5e844c0a19f66825385baa99d595336f396/mythtv:

Fix for wrong theme version being downloaded

. This fix only works for version 29 and up, it does not work for versions numbered 0.xx.
. Construct correct version for mythtv in all cases including build from git export zip.
. Download correct themes based on the version and not the branch.
. Only download themes from trunk when version is named with -pre, for example v29-pre.

Fixes #13020