1200862 - Add a command line option to not copy the profile specified in --profile each time a build is started

Status: RESOLVED FIXED

(Testing :: mozregression, enhancement)

Description

[Loic]

The current behaviour of Mozregression when --profile is specified consumes a lot of resources and time (at least on my machine) during a bisection (which should be fast!), because each time a build is started, the tool duplicates the custom profile to load a copy with the build.

Could you add an option to disable the copy of the profile specified in --profile and use it directly.

Comment 1

[Henrik Skupin [:whimboo][⌚️UTC+1]]

This is similar to what I have reported for Marionette via bug 1199588.

Comment 2

[Loic]

Another side issue is I need occasionally to modify the custom profile directly from the build loaded by Mozreg to keep some changes for a retry or for the next build (e.g.: e10s which is sometimes not fully disabled with builds from 2014 due to old prefs in about:config). If Mozreg duplicates the profile each time, I'm not able do that because the "primary" profile can't be modified.

Comment 3

[Julien Pagès (:parkouss)]

Attachment: WIP

Thanks for the bug report and the described use case, this looks like a great feature to have!

Well, this should be pretty good. I added a --profile-persistence option that can take three values:

'clone': the actual default
'clone-first': only clone one time, then every builds in the bisection will share that pofile
'reuse': no clone at all. may be quite dangerous because mozprofile (and so, mozregression) make some changes in the profile. That is, if a user uses that option with a custom profile, it will be modified forever.

The patch needs a bit more testing (e.g, check that we have no profile dirs not deleted at the end of mozregression run) but so far it looks good to me.

Comment 4

[Loic]

Just one question: with 'clone-first', if I enter "retry" for the 1st built launched, does Mozreg clone the profile a 2nd time or use the 1st clone?

Comment 5

[Julien Pagès (:parkouss)]

hm, it would reuse the same profile.

I think this is quite an advanced use case, maybe here it would be better to just close mozreg and run it again if you want a new profile.

If you are using the persist option anyway (this is recommended) you won't download the build again, the already downloaded one will be reused.

Comment 6

[Julien Pagès (:parkouss)]

Comment on attachment 8655990 [details] [review]
WIP

So I tested it pretty well, this looks all good to me!

Comment 7

[Julien Pagès (:parkouss)]

Comment on attachment 8655990 [details] [review]
WIP

As discussed on irc, wlach is quite busy, so I will r+ myslef here. Looks good to me and seems to works well.

Comment 8

[Julien Pagès (:parkouss)]

Landed in https://github.com/mozilla/mozregression/commit/6bce91d6da49178faee958463cfc1c81297570bd.