$ arc diff --trace
 ARGV  "c:/Users/Utkarsh/phabricator/arcanist/bin/../scripts/arcanist.php" "diff" "--trace"
 LOAD  Loaded "phutil" from "C:\Users\Utkarsh\phabricator\libphutil\src".
 LOAD  Loaded "arcanist" from "C:\Users\Utkarsh\phabricator\arcanist\src".
Config: Reading user configuration file "C:\Users\Utkarsh\AppData\Roaming/.arcrc"...
Config: Did not find system configuration at "C:\ProgramData\Phabricator/Arcanist/config".
Working Copy: Reading .arcconfig from "C:\mozilla-unified/.arcconfig".
Working Copy: Path "c:\mozilla-unified" is part of `hg` working copy "C:\mozilla-unified".
Working Copy: Project root is at "C:\mozilla-unified".
Config: Did not find local configuration at "C:\mozilla-unified\.hg\arc/config".
>>> [0] (+0) <http> https://phabricator.services.mozilla.com/api/user.whoami
<<< [0] (+2,819) <http> 2,819,438 us
>>> [1] (+2,823) <exec> $ set HGPLAIN=1 & hg status
<<< [1] (+3,759) <exec> 936,726 us
>>> [2] (+3,762) <event> diff.didCollectChanges <listeners = 0>
<<< [2] (+3,762) <event> 95 us
>>> [3] (+3,762) <exec> $ set HGPLAIN=1 & hg help phase
<<< [3] (+4,176) <exec> 414,118 us
>>> [4] (+4,176) <exec> $ set HGPLAIN=1 & hg branch
<<< [4] (+4,656) <exec> 479,484 us
>>> [5] (+4,656) <exec> $ set HGPLAIN=1 & hg log --branch "default" -r "draft()" --style default
<<< [5] (+5,336) <exec> 679,378 us
>>> [6] (+5,336) <exec> $ set HGPLAIN=1 & hg parents --style default --rev "."
<<< [6] (+5,906) <exec> 570,230 us
>>> [7] (+5,907) <exec> $ set HGPLAIN=1 & hg log --template "{node}<...binary data...>" --rev "('ea8190021659'::. - 'ea8190021659')" --branch "default" --
<<< [7] (+6,687) <exec> 780,255 us
>>> [8] (+6,691) <exec> $ set HGPLAIN=1 & hg log --template "{node}<...binary data...>{date|rfc822date}<...binary data...>" --rev "('ea8190021659'::. - 'ea8190021659')" --branch "default" --
<<< [8] (+7,358) <exec> 666,640 us
>>> [9] (+7,361) <exec> $ set HGPLAIN=1 & hg parents --template "{node}\n" --rev "f61671f593a8abbb9570521d95b64fbfbe7800d4"
<<< [9] (+8,034) <exec> 673,470 us
>>> [10] (+8,034) <http> https://phabricator.services.mozilla.com/api/differential.query
<<< [10] (+8,384) <http> 349,193 us
>>> [11] (+8,385) <http> https://phabricator.services.mozilla.com/api/differential.parsecommitmessage
<<< [11] (+8,808) <http> 422,206 us
>>> [12] (+8,808) <event> diff.willBuildMessage <listeners = 0>
<<< [12] (+8,815) <event> 7,106 us
>>> [13] (+8,823) <http> https://phabricator.services.mozilla.com/api/differential.getcommitmessage
<<< [13] (+9,169) <http> 346,464 us
>>> [14] (+9,177) <exec> $ "C:\Program Files (x86)\Notepad++\notepad++.exe" -multiInst -nosession "C:\Users\Utkarsh\AppData\Local\Temp\edit.8stcdx6gtpoogcg0\new-commit"

[2019-02-24 19:45:29] EXCEPTION: (Exception) Failed to passthru proc_open(): proc_open(): CreateProcess failed, error code - 2 at [<phutil>\src\future\exec\PhutilExecPassthru.php:103]
arcanist(head=master, ref.master=9581dd0f5272), phutil(head=master, ref.master=671ec8fb8f7a)
  #0 PhutilExecPassthru::execute() called at [<phutil>\src\future\exec\execx.php:50]
  #1 phutil_passthru(string, PhutilCommandString) called at [<phutil>\src\console\PhutilInteractiveEditor.php:122]
  #2 PhutilInteractiveEditor::invokeEditor(string, string, integer) called at [<phutil>\src\console\PhutilInteractiveEditor.php:77]
  #3 PhutilInteractiveEditor::editInteractively() called at [<arcanist>\src\workflow\ArcanistDiffWorkflow.php:1658]
  #4 ArcanistDiffWorkflow::getCommitMessageFromUser() called at [<arcanist>\src\workflow\ArcanistDiffWorkflow.php:1501]
  #5 ArcanistDiffWorkflow::buildCommitMessage() called at [<arcanist>\src\workflow\ArcanistDiffWorkflow.php:469]
  #6 ArcanistDiffWorkflow::run() called at [<arcanist>\scripts\arcanist.php:394]