Subrocesses not being killed

[jsongerber]

I'm using PHPStan to lint PHP code.

My understanding is that each save should trigger an analyze command, and if a previous process is still running, it should terminate before a new one starts.

When checking the running processes via require('lint').get_running(), it only shows a single process, which seems correct. However, it appears that multiple processes are being spawned:

As you can see, only one command is phpstan analyze, others are subprocesses that seems to be orphans, and keep hanging for long minutes, and can take a lot of memory, affecting performance.
This behavior seems similar to issue #521, so I’m wondering if this might be a regression.

Please tell me if you need any more information.

[lukoshkin]

I experience the same with shellcheck and flake8
I think it's major bug that must be fixed sooner
I can't mend the throttling anyhow but rebooting the laptop which is annoying

[mfussenegger]

This behavior seems similar to #521, so I’m wondering if this might be a regression.

There are test cases for the cancellation:

nvim-lint/spec/lint_spec.lua

Lines 29 to 54 in c9aa44f

	it("get_running returns running linter", function()
	local linter = {
	name = "dummy",
	cmd = "python",
	args = {"tests/loop.py"},
	parser = require("lint.parser").from_errorformat("%f:%l: %m")
	}
	lint.linters.dummy = linter
	local orig_lint = lint.lint
	---@type lint.LintProc
	local captured_proc
	---@diagnostic disable-next-line: duplicate-set-field
	lint.lint = function(...)
	captured_proc = assert(orig_lint(...))
	return captured_proc
	end
	lint.try_lint("dummy")
	assert.are.same({"dummy"}, lint.get_running())
	assert(captured_proc)
	captured_proc:cancel()
	vim.wait(500, function() return #lint.get_running() == 0 end)
	assert.are.same({}, lint.get_running())
	assert.is_false(captured_proc.handle:is_active())
	end)

So I'm fairly sure it didn't regress.

Could you check if you can terminate the orphan phpstan processes using kill ? nvim-lint first sends a sigint signal and if that doesn't work for ~10 seconds it sends a sigkill

[jsongerber]

Thank you for your response and for taking time to investigate.

At the time of creating this issue I had 8gb of ram, I since bought more and the issue seems to have disappear (or is less visible).

I tried to reproduce but the processes are now finishing too quick to be able to kill orphan ones (there are still orphans but they seem to not last long, and I don't know if they die by themselves or are killed by the plugin).

When I have time this week I'll try to edit phpstan to add sleep functions to simulate longer processes, but I don't know if it will work.

Maybe @lukoshkin can help if he can reproduce the problem.