1491408 - testing/geckodriver/build.rs is very slow if your hg config defaults to |--follow|

Status: RESOLVED FIXED

(Testing :: geckodriver, defect, P1)

Description

[Alex Gaynor [:Alex_Gaynor]]

In my system-wide hg config I make |hg log| default to |--follow|.

This causes: https://searchfox.org/mozilla-central/source/testing/geckodriver/build.rs#35 to be incredibly slow, since it prints the node for _every single commit_.

A solution would be to pass |--no-follow| in the invocation of |hg log|.

Comment 1

[Augie Fackler]

build.rs should set HGPLAIN=1 in the environment to avoid this.

Comment 2

[Andreas Tolfsen ❲:ato❳]

Looking at this I discovered another bug with build.rs.  For Mercurial
we use "hg log -r." in the CWD which selects the last commit in the
current working directory, but for git we just do "git log -1" which
picks the latest commit to the repository, whatever that may be.

Comment 3

[Andreas Tolfsen ❲:ato❳]

Disregard what I just said about "hg log -r.": it apparently selects
the parent/tip commit of the entire repository.

Comment 4

[Andreas Tolfsen ❲:ato❳]

Attachment: bypass local vcs config when invoking build script

This sets HGPLAIN and GIT_CONFIG_NOSYSTEM to bypass local user
version control system configuration when the build script is invoked.

If not set, the version control system's output could be influenced
by configuration settings.  It was for example discovered that if
you have "hg log" default to --follow, this slows down the Gecko
build significantly since it prints the node for every single commit.

According to hg(1) it is highly recommended for programs invoking
hg to set this.

Comment 5

[Henrik Skupin [:whimboo][⌚️UTC+1]]

Comment on attachment 9009588 [details] [diff] [review]
bypass local vcs config when invoking build script

Review of attachment 9009588 [details] [diff] [review]:
-----------------------------------------------------------------

::: testing/geckodriver/build.rs
@@ +53,5 @@
>      S: AsRef<OsStr>,
>      I: IntoIterator<Item = S>,
>  {
>      let mut cmd = Command::new(program);
> +    cmd.env("HGPLAIN", "1");

Note that this doesn't actually disable any configuration for Mercurial but only those which change the default output.

Comment 6

[Alex Gaynor [:Alex_Gaynor]]

Thanks for jumping on this!

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/mozilla-central/rev/b7f409bd51c8
bypass local vcs config when invoking build script. r=whimboo a=Aryx

Comment 8

[Sebastian Hengst [:aryx] (needinfo me if it's about an intermittent or backout)]

https://hg.mozilla.org/mozilla-central/rev/b7f409bd51c8