Lua fails to initialize due to error in dt 5.6 on Windows 11

[lefth]

Symptom: panels/buttons that are created by lua scripts no longer exist. The "Lua options" section is not present in the application preferences. And the log file contains:

3.9410 LUA ERROR : ...table\share\darktable/lua-scripts/lib/dtutils\string.lua:641: attempt to concatenate a nil value (local 'HOME')

It looks like this line tries to get the path from variable "HOMEPATH", which is not a normal windows path. It should be "USERPROFILE":

lua-scripts/lib/dtutils/string.lua

Line 640 in b24dd18

local HOME = dt.configuration.running_os == "windows" and os.getenv("HOMEPATH") or os.getenv("HOME")

I tested locally by changing the variable name in C:/Program Files/Darktable/share/darktable/lua-scripts/lib/dtutils/string.lua, and it fixed the problem.

I am using darktable, based on commit b3c41a1ee272642eb96a9eba46e2fcbda6fa9ad9, which is a few commits past version 5.6, with some additional commits. I don't think there are lua changes in the tree.

I think this problem started occurring when darktable started using internally bundled scripts, which effectively updated my scripts. However the scripts in my user directory were only a few months old, and I can't find a recent change that looks like it would trigger this error.

[wpferguson]

I think this problem started occurring when darktable started using internally bundled scripts, which effectively updated my scripts

If the user has installed the lua-scripts, or already had them installed, then the bundled scripts are not used. The script search path is always user lua directory first. If the lua-scripts are installed in the user config directory, then the version of the scripts is checked against the latest version of the scripts, and the user installed lua-scripts are updated if there is a newer version available.

HOMEPATH has been the variable used to get the windows user's home directory for more than 3 years and it's worked without a problem.

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You can run a quick test to see if there is an issue with your installed scripts. Simply rename your lua directory. When darktable starts and doesn't find it then the bundled scripts will be used instead.