fix: Exit code 1 warning at the end of a debug session on Windows

[Aeceon]

On Windows, when using a server type debug adapter that is executed (in this case codelldb) I received the following warning after a debug session ended:

...codelldb.CMD exited with code 1

Changing "sigterm" to "SIGTERM" in the client close function fixes this.

[Aeceon]

I've jumped the gun here. I should have opened an issue first.

After receiving the exit code 1 warning, I read the Neovim documentation on kill and noticed that sigterm was in uppercase here. I made this change and the debug adapter correctly exited with code 0. I should have looked into it further because It correctly exits with code 0 on Windows for everything but "sigterm" (lowercase). For instance:

handle:kill("blah")

This sees the debug adapter exit with code 0 as well.

Steps to reproduce the original issue on Windows (not WSL):

1. The following adapter configuration automatically provided by mason-nvim-dap:

local dap = require('dap')

dap.adapters.codelldb = {
	type = 'server',
	port = '${port}',
	executable = {
		command = vim.fn.exepath('codelldb'),
		args = { '--port', '${port}' },
	},
}

if vim.fn.has('win32') == 1 then
	dap.adapters.codelldb.executable.detached = false
end

dap.configurations.cpp = {
  {
    name = 'Launch',
    type = 'codelldb',
    request = 'launch',
    program = function()
      return vim.fn.input('Path to executable: ', vim.fn.getcwd() .. '/', 'file')
    end,
    cwd = '${workspaceFolder}',
    stopOnEntry = false,
    args = {},
}

dap.configurations.c = dap.configurations.cpp
dap.configurations.rust = dap.configurations.cpp

2. Compile a standard hello world program in C with MSVC ("cl /Zi main.c").
3. Open the hello world source file in Neovim.
4. Set a breakpoint before print.
5. Start a debug session with the compiled program.
6. Hit continue once the breakpoint has been reached.

I then receive the following warning when the debug session ends (generated on line 1152 of session.lua):

...codelldb.CMD exited with code 1

This doesn't happen if handle:kill is passed anything other than "sigterm" (lowercase).

[mfussenegger]

Could you try with sigint ?

Changing it to SIGTERM prevents it from terminating the process on linux, and it again leaks processes if they don't stop by themselves after a debug session (which vscode-js-debug doesn't).

[mfussenegger]

@Aeceon did you have a chance to try with sigint?

[Aeceon]

Sorry, I forgot I hadn't updated this. sigint gave the same "exited with code 1" error. sighup, however, works. I changed the code to only use this on Windows and stick to sigterm otherwise.