1032484 - mach can't find objdir when using GECKO_PATH in a b2g build

Status: RESOLVED FIXED

(Firefox Build System :: General, defect)

Description

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

I was trying to use mach to run the b2g emulator tests, since it's supposed to be the way to run things.  I'm doing this in a b2g tree located in /home/dbaron/builds/B2G-master-emulator with a .userconfig file that looks like this:

=====
export B2G_DEBUG=1

# use my mozilla-central tree, with patches
export GECKO_PATH=/home/dbaron/builds/ssd/mozilla-central/mozilla

if [ "$B2G_DEBUG" ]
then
    GECKO_OBJDIR=objdir-gecko-debugopt
else
    GECKO_OBJDIR=objdir-gecko
fi
=====

However, trying to use mach in this directory (B2G-master-emulator) gives the error:
=====

$ ./mach mochitest-remote
It looks like you tried to run a mach command from an invalid context. The mochitest-remote
command failed to meet the following conditions: 

  is_b2g - Must have a Boot to Gecko build.

Run |mach help| to show a list of all commands available to the current context.
=====

(Note that the is_emulator condition passed.)

Some debugging shows that the underlying problem is the os.path.join call here:
https://hg.mozilla.org/mozilla-central/file/606848e8adfc/python/mozbuild/mozbuild/base.py#l206
which is combining the variables:

topsrcdir = /home/dbaron/builds/ssd/mozilla-central/mozilla
topobjdir = objdir-gecko-debugopt

In this build setup, these aren't the right things to combine.

It's not (yet, anyway) clear to me how this ought to be fixed.

Comment 1

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Attachment: my workaround for now (diff against B2G repo)

Horrible hack, I think.

Comment 2

[Andrew Halberstadt [:ahal]]

Comment on attachment 8448323 [details] [diff] [review]
my workaround for now (diff against B2G repo)

Review of attachment 8448323 [details] [diff] [review]:
-----------------------------------------------------------------

::: tools/mach_b2g_bootstrap.py
@@ +192,5 @@
> +    # Absolutize GECKO_OBJDIR here, since otherwise mach will try to
> +    # absolutize it relative to the topsrcdir, which might be different
> +    # if GECKO_PATH is in use.
> +    if os.environ.get('GECKO_OBJDIR') is not None:
> +       os.environ['GECKO_OBJDIR'] = os.path.join(b2g_home, os.environ['GECKO_OBJDIR'])

Hackiness is relative ;). This makes sense, and as far as I've been able to determine should do the right thing in all cases. I don't think there's a better way of fixing this that won't break other obscure corner cases somewhere else. Let me know if you need help getting this landed.

Comment 3

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

OK; I created a pull request at https://github.com/mozilla-b2g/B2G/pull/363 , but I'm not sure what the procedures for landing are (or who the set of people with permission to merge pull requests are).

Comment 4

[Andrew Halberstadt [:ahal]]

Since this is only touching the mach bootstrap script, I don't think we need anyone else's review. Merged:
https://github.com/mozilla-b2g/B2G/commit/159e5bcbe7c8594322a43f13f7cd53de012fd026