[Lldb-commits] [lldb] b4a6e63 - [lldb/Target] Rework the way the inferior environment is created

[Adrian McCarthy via lldb-commits]

On Wed, Mar 25, 2020 at 9:49 AM Adrian McCarthy <amccarth at google.com> wrote:

>
>
> On Wed, Mar 25, 2020 at 9:10 AM Pavel Labath <pavelo at centrum.sk> wrote:
>
>> On 25/03/2020 01:04, Adrian McCarthy wrote:
>> > I took a stab at this, but I'm not seeing any new test failures.
>>
>> That is odd.
>>
>> I was doing some stuff on windows today, so I figured I'd take a stab at
>> this. I was kind of right that the check in ProcessLauncher windows
>> prevents us from passing an empty environment.
>>
>> However, the interesting part starts when I tried to remove that check.
>> Then the test started behaving nondeterministically -- sometimes passing
>> and sometimes failing due to ERROR_INVALID_PARAMETER being returned from
>> CreateProcessW. I can see how windows might need some environment
>> variables to start up a process correctly, but I do not understand why
>> this should be nondeterministic...
>>
>
> Oh, I have a guess.  CreateProcessW takes a pointer to an environment
> block.  If that pointer is null, the process will inherit the parent
> environment.  If you want to pass it an empty environment, you have to have
> a valid pointer to an empty string (or possibly to a string with TWO
> terminating '\0's).
>

Scratch the "or possibly."  You definitely need two terminating zeros.
Since it's in UTF-16, it wants two L'\0', which is four consecutive zero
bytes.


>
>
>> This is beyond my knowledge of windows. It might be interesting to
>> reduce this to a simple test case (independent of lldb) and show it to
>> some windows expert.
>>
>> I am attaching a patch with the lldb changes I've made, in case you want
>> to play around with it.
>>
>> > I assume
>> > the problem you're seeing is in TestSettings.py, but I've never figured
>> > out how to run individual Python-based lldb tests since all the
>> > dotest.py stuff was re-written.
>>
>> These days we have multiple ways of achieving that. :)
>>
>> One way would be via the "check-lldb-api-commands-settings" target which
>> would run all tests under api/commands/settings (i.e. TestSettings.py
>> and TestQuoting.py).
>>
>> Another option would be via the lldb-dotest script.
>> "python bin\lldb-dotest -p TestSettings.py" would just run that single
>> file. That script passes all of its options to dotest, so you can use
>> any of the dotest options that you used to use.
>>
>
> I would be thrilled if either of those worked for me.  Somehow, check-lldb
> works, but the check-lldb-... doesn't.
>
> The lldb-dotest solution always fails for me because I can't figure out
> WTF it wants for PYTHONHOME and PYTHONPATH.
>
>
>>
>> pl
>>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/lldb-commits/attachments/20200325/a17ee25d/attachment-0001.html>