node aborts with --debug when it self-exits

[sam-github]

• Version: 7.x, 6.x, 4.x (there is no --debug in master)
• Platform: Linux (at least)
• Subsystem: debugger

node --debug test/fixtures/printA.js (node's test/fixtures), node --debug -p process.features, `node --debug -e "console.log('hi')", all abort on https://github.com/nodejs/node/blob/610ac7d8581012e627a4f4b67450b423ddbda415/src/debug-agent.cc#L147 with UV_EBUSY, because there is still work.

The check seems invalid to me, uv_run() runs with NOWAIT, so its not guaranteed to run til the loop is empty, just until there is nothing that would involve blocking, IIRC.

I tried adding setTimeout() and setImmediate() into printA.js, same thing. I think the debugger just doesn't expect to be used to debug a node process which is not long-lived.

core/node (v8.x *$% u=) % ./node --debug test/fixtures/printA.js
(node:27775) [DEP0062] DeprecationWarning: node --debug is deprecated. Please use node --inspect instead.
Debugger listening on 127.0.0.1:5858
A
err -16/home/sam/w/core/node/out/Release/node[27775]: ../src/debug-agent.cc:148:void node::debugger::Agent::Stop(): Assertion `(err) == (0)' failed.
 1: node::Abort() [./node]
 2: node::Assert(char const* const (*) [4]) [./node]
 3: 0x5645e6a64394 [./node]
 4: node::debugger::Agent::~Agent() [./node]
 5: node::Environment::~Environment() [./node]
 6: node::Start(uv_loop_s*, int, char const* const*, int, char const* const*) [./node]
 7: node::Start(int, char**) [./node]
 8: __libc_start_main [/lib/x86_64-linux-gnu/libc.so.6]
 9: _start [./node]
zsh: abort (core dumped)  ./node --debug test/fixtures/printA.js

[sam-github]

/to @indutny

[gireeshpunathil]

Unable to reproduce this on v6.x on Linux:

$ node --debug -e "console.log('hi')"
Debugger listening on [::]:5858
hi
^C

$ node --debug -p process.features

Debugger listening on [::]:5858
{ debug: false,
  uv: true,
  ipv6: true,
  tls_npn: true,
  tls_alpn: true,
  tls_sni: true,
  tls_ocsp: true,
  tls: true }
^C

Does anyone know what fixed this? (Sam is on an year-long vacation)

[gireeshpunathil]

basically uv_loop_close returned error when tearing down the Environment and then the agent was the issue, and that seem to work now.

[bnoordhuis]

The inspector has been significantly reworked, there's probably no single commit that's responsible. I'll go ahead and close this out since it's working now.