conformance.md

PM2 conformance

tests/conformance/run.js runs the same ecosystem file under PM2 and under Vexor, each in an isolated home, and compares what a probe app experienced (runs, argv, cwd, environment, instance numbers, stop signal) with what each tool reported (status, restart count). Run it in a throwaway container with pm2 and vexor on PATH:

docker run --rm -v "$PWD/dist":/bin2 -v "$PWD/tests/conformance":/c:ro node:22-alpine \
  sh -c 'npm i -g pm2@7.1.0 && cp /bin2/vexor /usr/local/bin/ && node /c/run.js --out /bin2/report.md'

Summary

Latest run: PM2 7.1.0 vs Vexor 0.1.1, 11 scenarios, 10 identical, 1 intentional difference.

The harness found two real incompatibilities in 0.1.0, both fixed for 0.1.1:

• max_restarts: N allowed N + 1 runs before errored; PM2 allows N. max_restarts: 0 now means PM2's default, 16.
• Graceful stop sent SIGTERM; PM2 sends SIGINT. Vexor now sends SIGINT by default, and the new kill_signal setting chooses another signal.

Intentional difference: wait_ready without a ready signal

When listen_timeout expires and the app never called process.send('ready'), PM2 marks the app online anyway. Vexor treats it as a failed start (stopped, counted against max_restarts, restarted with backoff; errored when the budget runs out), so a broken app is never reported healthy and a reload never retires a working process in favour of one that never became ready.

Not compared

Vexor limits automatic restarts to one per second per instance, while PM2 restarts immediately with restart_delay: 0. The final counts match (see crash-budget-0), but Vexor reaches them more slowly; the harness waits long enough for both.

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Results

Generated by tests/conformance/run.js: PM2 7.1.0 vs vexor 0.1.1, Node v22.23.4, linux/arm64, 2026-10-23.

Each scenario runs the same ecosystem file under both tools. Rows show what the probe app saw and what each tool reported; bold rows differ.

crash-budget

How many runs before errored with max_restarts 3?

	PM2	Vexor
runs	3	3
statuses	["errored"]	["errored"]
restarts	[2]	[2]
argv	[]	[]
cwd	"."	"."
mode	–	–
a	–	–
insts	["0"]	["0"]
signal	–	–

crash-budget-0

How many runs before errored with max_restarts 0?

	PM2	Vexor
runs	16	16
statuses	["errored"]	["errored"]
restarts	[15]	[15]
argv	[]	[]
cwd	"."	"."
mode	–	–
a	–	–
insts	["0"]	["0"]
signal	–	–

crash-budget-1

How many runs before errored with max_restarts 1?

	PM2	Vexor
runs	1	1
statuses	["errored"]	["errored"]
restarts	[0]	[0]
argv	[]	[]
cwd	"."	"."
mode	–	–
a	–	–
insts	["0"]	["0"]
signal	–	–

vexor said: crash-budget-1 0 errored - - 0

paths

Relative cwd and script resolution

	PM2	Vexor
runs	1	1
statuses	["online"]	["online"]
restarts	[0]	[0]
argv	[]	[]
cwd	"sub"	"sub"
mode	–	–
a	–	–
insts	["0"]	["0"]
signal	"SIGINT"	"SIGINT"

env-args

env + env_production with --env production; args string splitting; instance var

	PM2	Vexor
runs	2	2
statuses	["online","online"]	["online","online"]
restarts	[0,0]	[0,0]
argv	["x","y z","w"]	["x","y z","w"]
cwd	"."	"."
mode	"prod"	"prod"
a	"1"	"1"
insts	["0","1"]	["0","1"]
signal	"SIGINT"	"SIGINT"

stop-exit-codes

Exit 0 with stop_exit_codes [0]

	PM2	Vexor
runs	1	1
statuses	["stopped"]	["stopped"]
restarts	[0]	[0]
argv	[]	[]
cwd	"."	"."
mode	–	–
a	–	–
insts	["0"]	["0"]
signal	–	–

autorestart-false

Crash with autorestart false

	PM2	Vexor
runs	1	1
statuses	["stopped"]	["stopped"]
restarts	[0]	[0]
argv	[]	[]
cwd	"."	"."
mode	–	–
a	–	–
insts	["0"]	["0"]
signal	–	–

stop-signal

Which signal does stop send?

	PM2	Vexor
runs	1	1
statuses	["stopped"]	["stopped"]
restarts	[0]	[0]
argv	[]	[]
cwd	"."	"."
mode	–	–
a	–	–
insts	["0"]	["0"]
signal	"SIGINT"	"SIGINT"

wait-ready-missing

wait_ready with no ready signal (listen_timeout 1500)

	PM2	Vexor
runs	1	1
statuses	["online"]	["errored"]
restarts	[0]	[0]
argv	[]	[]
cwd	"."	"."
mode	–	–
a	–	–
insts	["0"]	["0"]
signal	"SIGINT"	"SIGINT"

wait-ready-ok

wait_ready with a ready signal

	PM2	Vexor
runs	1	1
statuses	["online"]	["online"]
restarts	[0]	[0]
argv	[]	[]
cwd	"."	"."
mode	–	–
a	–	–
insts	["0"]	["0"]
signal	"SIGINT"	"SIGINT"

cluster-instances

Cluster mode with 2 instances: instance numbers

	PM2	Vexor
runs	2	2
statuses	["online","online"]	["online","online"]
restarts	[0,0]	[0,0]
argv	[]	[]
cwd	"."	"."
mode	–	–
a	–	–
insts	["0","1"]	["0","1"]
signal	"SIGINT"	"SIGINT"