Conflict between Eclipse JGit and Cygwin HOME

[Brian Inglis]

On 2020-03-17 07:45, David Karr via Cygwin wrote:
> On Mon, Mar 16, 2020 at 11:20 PM Brian Inglis wrote:
>> On 2020-03-16 19:03, Andrey Repin wrote:
>>>> I've been running Cygwin on my Windows 10 laptop for quite a while.  I 
>>>> use git in Eclipse and in the shell.
>>>>
>>>> What I'm describing isn't really a bug with Cygwin, but it breaks 
>>>> because of the interaction with Cygwin, and I'm trying to find out a
>>>> reasonable way to fix this.
>>>>
>>>> Over the weekend, I upgraded Windows 10 from 1709 to 1809.  Somehow 
>>>> after that I have messed up how git is used in Eclipse.
>>>>
>>>> The Eclipse JGit framework figures out where my git config is by 
>>>> checking things in the following order:
>>>>
>>>> - 1. %HOME% if set,
>>>> - 2. %HOMEDRIVE%\%HOMEPATH%, if %HOMEDRIVE% is set,
>>>> - 3. %HOMESHARE% if set,
>>>> - 4. Java system property "user.home".
>>>>
>>>> The HOMEDRIVE, HOMEPATH, and HOMESHARE variables are set by my work
>>>> infrastructure, and I appear to have no control over them. The resulting
>>>> %HOMEDRIVE%\%HOMEPATH% doesn't even exist.
>>>
>>> It should, that's nonsense. File an issue with your infrastructure team.
>>>
>>>> The HOME variable is set by Cygwin, apparently.
>>>
>>> No, it only set HOME if it is not set yet, and even then only for login
>>> shells.
>>>
>>>> It is set to "/home/<myuid>".
>>>
>>> What "myid" is supposed to mean? HOME is set to /home/$USER by default, 
>>> but can be overridden with proper nsswitch configuration.
>>>
>>>> I'm guessing that JGit looks at that and can't do
>>>> anything with it, so it goes down the list and doesn't find anything
>>>> useful. I end up with bad git config values.
>>>
>>> Just install Git for Windows, but don't add it to %PATH% in any way, 
>>> shape or form. Then configure Eclipse to use that git instead of Cygwin
>>> one.
>>>
>>>> The workaround I've figured out is a batch file that sets HOME to the 
>>>> expected Windows HOME, and then executes its command-line parameters. I
>>>> changed the target property in the Eclipse shortcut to add the full 
>>>> path to this batch file at the front of the command line, and then I
>>>> have to find the eclipse.exe file and get the desktop icon from it.
>>>> I'll have to do this every time I install a new Eclipse distribution.>>>
>>> Start by solving the issue from its head.
>>> Fix your %HOMEDRIVE%/%HOMEPATH%/%HOMESHARE%, configure your nsswitch to 
>>> point to an existing profile path.
>>
>> Your problem seems to be with your Windows network profile and Windows 
>> programs, nothing to do with Cygwin.
>> Fixing the former will probably fix the latter.
> 
> If it wasn't obvious, I'm trying to find a solution, not assign blame.  Of 
> course it has "something to do with Cygwin", because I'm using it, and Cygwin
> and WIndows are using a shared resource, the "HOME" variable. Cygwin and
> Windows try to use it for different purposes.  There's nothing I can do about
> the "Windows network profile".

Andrey and myself are trying to point you towards solving your problem, which
appears to be from your Windows network profile, which is set up by your Windows
support team, and is broken under your upgraded release.

You need to contact your corporate Windows support team and have them help to
fix your profile problem.

You can try to do so yourself by renaming your profile folder and immediately
restarting your system.
You will of course lose your settings, but this is a standard corporate Windows
support approach, as is reimaging your system.
To that end, restoring your system, by rolling back the upgrade, to its
pre-upgrade state, would also be a viable approach for you to try.

We are unconcerned about blame, only pointing at the likely cause, and your
denial that anything can be done about your broken profile settings.

>> But if your work infrastructure does not yet support W10 1809 (do you 
>> really mean that release, not the current 1909 release?) you should not
>> have upgraded, and any breakage is down to you.
> 
> Again, you took this as me trying to assign blame, which is pointless.
> 
> Yes, I meant 1809, and although I performed the upgrade manually, it would
> have been done automatically in the near future if I hadn't, so there was
> no choice there.

Your corporate upgrade would have been applied using a different approach, with
relevant settings saved and restored, or replaced in a way compatible with your
corporate environment. A lot of work and testing is done by corporate Windows
support groups to minimize problems and their subsequent support load after
upgrades.

>> For Cygwin options see:
>>
>> https://cygwin.com/cygwin-ug-net/ntsec.html#ntsec-mapping-nsswitch-desc
> 
> Yes, I've seen that, and considered my options there, but I don't think
> that will address this situation.  The problem is the contents of the
> "HOME" variable. It doesn't matter where my Cygwin HOME directory actually
> resides.

That section shows how to override HOME under Cygwin using an XML like SAM Comment:

    $ net user $USER /comment:"<cygwin home=\"/home/$USER\" />"

which may need some extra quoting to get the quotes into the comment:
you may then symlink your effective home directory to /home/$USER.

The docs are available locally if you install cygwin-doc and use:

    $ cygstart /usr/share/doc/cygwin-doc/html/cygwin-ug-net/ntsec.html

but cygstart does not support fragments in file URLs.

-- 
Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada

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