When executing a repository passthru command via CommandEngine, don't set a timeout

Summary:
Ref T13541. The passthru future does not have time limit behavior, so if we reach this code we currently fail.

Phabricator never reaches this code normally, but this code is reachable during debugging if you try to foreground a slow fetch to inspect it.

Passthru commands generally only make sense to run interactively, and the caller or control script can enforce their own timeouts (usually by pressing "^C" with their fingers).

Test Plan: Used a debugging script to run ref-by-ref fetches in the foreground.

Maniphest Tasks: T13541

Differential Revision: https://secure.phabricator.com/D21284

Author: epriestley

src/applications/diffusion/protocol/DiffusionCommandEngine.php

@@ -120,14 +120,15 @@ public function getSudoAsDaemon() {
   public function newFuture() {
     $argv = $this->newCommandArgv();
     $env = $this->newCommandEnvironment();
+    $is_passthru = $this->getPassthru();
 
     if ($this->getSudoAsDaemon()) {
       $command = call_user_func_array('csprintf', $argv);
       $command = PhabricatorDaemon::sudoCommandAsDaemonUser($command);
       $argv = array('%C', $command);
     }
 
-    if ($this->getPassthru()) {
+    if ($is_passthru) {
       $future = newv('PhutilExecPassthru', $argv);
     } else {
       $future = newv('ExecFuture', $argv);
@@ -139,7 +140,9 @@ public function newFuture() {
     // to try to avoid cases where `git fetch` hangs for some reason and we're
     // left sitting with a held lock forever.
     $repository = $this->getRepository();
-    $future->setTimeout($repository->getEffectiveCopyTimeLimit());
+    if (!$is_passthru) {
+      $future->setTimeout($repository->getEffectiveCopyTimeLimit());
+    }
 
     return $future;
   }