Process appear as online with wait_ready even when launch fails

What's going wrong?

An app started with:

"wait_ready":true,
"max_restarts":3,
"min_uptime": "2m"

Appear as online even if the app crashes at every launch and the ready signal is never emitted.

How could we reproduce this issue?

1 - Create a sample ecosystem.config.json file as

{
    "apps": [
        {
            "name": "mitown",
            "script": "index.js",
            "watch": false,
            "cwd": "someapp/",
            "exec_mode" : "cluster",
            "node_args": "--max_old_space_size=4096",
            "wait_ready":true,
            "kill_timeout": 12000,
            "listen_timeout": 100000,
            "max_memory_restart": "1536M",
            "restart_delay": 4000,
            "shutdown_with_message" : true,
            "max_restarts":3,
            "min_uptime": "2m",
            "instances":1
       }
   ]
}

2 - create someapp/index.js file with these contents:

undefinedFunctionCall()

3 - run pm2 start ecosystem.config.json

4 - wait for the app to crash 3 times, then launch pm2 list. The app appear as online with memory usage as 0b

Looks like the same issue of #4355

Supporting information

--- PM2 report ----------------------------------------------------------------
Date                 : Wed Mar 10 2021 14:33:04 GMT+0000 (Coordinated Universal Time)
===============================================================================
--- Daemon -------------------------------------------------
pm2d version         : 4.4.1
node version         : 12.20.1
node path            : /usr/bin/pm2
argv                 : /usr/bin/node,/usr/lib/node_modules/pm2/lib/Daemon.js
argv0                : node
user                 : onit
uid                  : 1001
gid                  : 1001
uptime               : 35min
===============================================================================
--- CLI ----------------------------------------------------
local pm2            : 4.4.1
node version         : 12.20.1
node path            : /usr/bin/pm2
argv                 : /usr/bin/node,/usr/bin/pm2,report
argv0                : node
user                 : onit
uid                  : 1001
gid                  : 1001
===============================================================================
--- System info --------------------------------------------
arch                 : x64
platform             : linux
type                 : Linux
cpus                 : Intel(R) Core(TM) i5-5300U CPU @ 2.30GHz
cpus nb              : 1
freemem              : 268554240
totalmem             : 1028964352
home                 : /home/onit
===============================================================================
--- PM2 list -----------------------------------------------
┌─────┬────────────────┬─────────────┬─────────┬─────────┬──────────┬────────┬──────┬───────────┬──────────┬──────────┬──────────┬──────────┐
│ id  │ name           │ namespace   │ version │ mode    │ pid      │ uptime │ ↺    │ status    │ cpu      │ mem      │ user     │ watching │
├─────┼────────────────┼─────────────┼─────────┼─────────┼──────────┼────────┼──────┼───────────┼──────────┼──────────┼──────────┼──────────┤
│ 2   │ mit-ray        │ default     │ 1.0.10  │ fork    │ 32273    │ 2m     │ 0    │ online    │ 0.2%     │ 43.3mb   │ onit     │ disabled │
│ 0   │ mitown         │ default     │ 1.0.0   │ cluster │ 0        │ 2m     │ 2    │ online    │ 0%       │ 0b       │ onit     │ disabled │
│ 1   │ nats-server    │ default     │ 1.0.1   │ fork    │ 32265    │ 2m     │ 0    │ online    │ 0.2%     │ 35.7mb   │ onit     │ disabled │
└─────┴────────────────┴─────────────┴─────────┴─────────┴──────────┴────────┴──────┴───────────┴──────────┴──────────┴──────────┴──────────┘
===============================================================================
--- Daemon logs --------------------------------------------
/home/onit/.pm2/pm2.log last 20 lines:
PM2        | 2021-03-10T14:30:37: PM2 log: App [nats-server:1] exited with code [0] via signal [SIGKILL]
PM2        | 2021-03-10T14:30:37: PM2 log: pid=20102 msg=process killed
PM2        | 2021-03-10T14:30:37: PM2 log: pid=20091 msg=process killed
PM2        | 2021-03-10T14:30:43: PM2 log: App [mitown:0] starting in -cluster mode-
PM2        | 2021-03-10T14:30:43: PM2 log: App [nats-server:1] starting in -fork mode-
PM2        | 2021-03-10T14:30:43: PM2 log: App [nats-server:1] online
PM2        | 2021-03-10T14:30:43: PM2 log: App [mit-ray:2] starting in -fork mode-
PM2        | 2021-03-10T14:30:43: PM2 log: App [mit-ray:2] online
PM2        | 2021-03-10T14:30:45: PM2 log: App name:mitown id:0 disconnected
PM2        | 2021-03-10T14:30:45: PM2 log: App [mitown:0] exited with code [0] via signal [SIGINT]
PM2        | 2021-03-10T14:30:49: PM2 log: App [mitown:0] starting in -cluster mode-
PM2        | 2021-03-10T14:30:49: PM2 log: App name:mitown id:0 disconnected
PM2        | 2021-03-10T14:30:49: PM2 log: App [mitown:0] exited with code [0] via signal [SIGINT]
PM2        | 2021-03-10T14:30:53: PM2 log: App [mitown:0] starting in -cluster mode-
PM2        | 2021-03-10T14:30:54: PM2 log: App name:mitown id:0 disconnected
PM2        | 2021-03-10T14:30:54: PM2 log: App [mitown:0] exited with code [0] via signal [SIGINT]
PM2        | 2021-03-10T14:30:54: PM2 log: Script /home/onit/apps/mitown/index.js had too many unstable restarts (3). Stopped. "errored"
PM2        | 2021-03-10T14:32:24: PM2 log: App [mitown:0] online
PM2        | 2021-03-10T14:32:29: PM2 log: App [mitown:0] online
PM2        | 2021-03-10T14:32:33: PM2 log: App [mitown:0] online

Start with the supplied ecosystem.config.json and someapp/index.js, reproduce the issue with pm2 start ecosystem.config.json, then check pm2 list and the daemon logs after three crashes. Trace why the stopped process is reported as online; done means a launch that never emits the ready signal is shown as errored or stopped rather than online.