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Date: Sun, 15 Sep 2019 18:55:19 +0000
From: Eric Wong <e@80x24.org>
To: Alyssa Ross <hi@alyssa.is>
Cc: meta@public-inbox.org
Subject: Re: [PATCH] t/spawn: fix with unusual env locations
Message-ID: <20190915185519.GA4891@dcvr>
References: <20190915134819.1406-1-hi@alyssa.is>
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Alyssa Ross <hi@alyssa.is> wrote:
> The call to spawn clears the environment, including PATH.  This means
> that an env in a non-default location wouldn't be found, while all the
> other tests work because they use PATH.  We can fix this by looking up
> which PATH to use beforehand.

Thanks for reporting this issue, but... is that it?
We also use spawn() for 'git', among other things...

> I ran into this when packaging public-inbox for Nixpkgs.  We build in
> a chroot, and in this case the env I wanted to use was at
> /nix/store/7rmjki86923bw1inx0czpp4wgy0kk687-coreutils-8.31/bin/env.

The Inline::C version of spawn (enabled by setting
PERL_INLINE_DIRECTORY) should already be using the result of
which() for every execve(2) call it does.

For the pure Perl codepath, this ought to be a more encompassing
alternative to your patch:

diff --git a/lib/PublicInbox/SpawnPP.pm b/lib/PublicInbox/SpawnPP.pm
index 25c8c87f..29b13371 100644
--- a/lib/PublicInbox/SpawnPP.pm
+++ b/lib/PublicInbox/SpawnPP.pm
@@ -38,11 +38,13 @@ sub pi_fork_exec ($$$$$$) {
 		}
 
 		if ($ENV{MOD_PERL}) {
-			exec qw(env -i), @$env, @$cmd;
+			exec which('env'), '-i', @$env, @$cmd;
 			die "exec env -i ... $cmd->[0] failed: $!\n";
 		} else {
 			local %ENV = map { split(/=/, $_, 2) } @$env;
-			exec @$cmd;
+			my @cmd = @$cmd;
+			$cmd[0] = $f;
+			exec @cmd;
 			die "exec $cmd->[0] failed: $!\n";
 		}
 	}

Can you confirm?  Thanks.