escaping pass-through arguments is too eager

Background

When trying to use concurrently with --passthrough-arguments option, any passed arguments get escaped too eagerly.

The issue has been observed while developing an application when trying to concurrently run a local web server and gherkin-testcafe for testing with the latter requring tags to start with @ character.

Since that application can't be shared here for legal reasons I've tried a simpler scenario which is reproducing the issue, too.

Scenario

• windows platform
• npm 10.5.2
• node 20.13.1
• concurrently 8.2.2
• files:
  • package.json contains scripts:

    {"scripts": {
        "foo": "concurrently -k -n \"bar,baz\" -P npm:foo:bar \"npm:foo:baz -- {@}\"",
        "foo:bar": "node block.js",
        "foo:baz": "node log.js",
    }}
    

  • file block.js looks like this:

    setTimeout(() => console.log("delayed"), 1000);
    

  • file log.js looks like this:

    console.dir(process.argv);
    

Test

invoke without arguments

$ npm run foo

> logistics-client@0.0.0 foo
> concurrently -k -n "bar,baz" -P npm:foo:bar "npm:foo:baz -- {@}"

[bar] 
[bar] > logistics-client@0.0.0 foo:bar
[bar] > node block.js
[bar]
[baz]
[baz] > logistics-client@0.0.0 foo:baz
[baz] > node log.js
[baz]
[baz] [
[baz]   'C:\\Program Files\\nodejs\\node.exe',
[baz]   'C:\\Users\\cepharum\\PhpstormProjects\\UID\\Logistics\\WebClient\\Source\\UiNew\\log.js'
[baz] ]
[baz] npm run foo:baz --  exited with code 0
--> Sending SIGTERM to other processes..
[bar] npm run foo:bar exited with code 1

looks good ... setup is working as expected

invoke with arguments to pass

$ npm run foo -- -- --tags=@foo

> logistics-client@0.0.0 foo
> concurrently -k -n "bar,baz" -P npm:foo:bar "npm:foo:baz -- {@}" -- --tags=@foo

[bar]
[bar] > logistics-client@0.0.0 foo:bar
[bar] > node block.js
[bar]
[baz]
[baz] > logistics-client@0.0.0 foo:baz
[baz] > node log.js --tags\=\@foo
[baz]
[baz] [
[baz]   'C:\\Program Files\\nodejs\\node.exe',
[baz]   'C:\\Users\\cepharum\\PhpstormProjects\\UID\\Logistics\\WebClient\\Source\\UiNew\\log.js',
[baz]   '--tags\\=\\@foo'
[baz] ]
[baz] npm run foo:baz -- --tags\=\@foo exited with code 0
--> Sending SIGTERM to other processes..
[bar] npm run foo:bar exited with code 1

Problem here:

• the assignment operator gets escaped
• the @ gets escaped

Escaping seems to be eligible due to cmd.exe being involved. But eventually that escaping is found in invoked sub-process, too. Trying to fix it in that sub-process is not an option for it is a third-party application (gherkin-testcafe).

gherkin-testcafe illustrates the provision of tags without assignment operator, so I tried that one, too:

$ npm run foo -- -- --tags @foo

> logistics-client@0.0.0 foo
> concurrently -k -n "bar,baz" -P npm:foo:bar "npm:foo:baz -- {@}" -- --tags @foo

[baz] 
[baz] > logistics-client@0.0.0 foo:baz
[baz] > node log.js --tags \@foo
[baz] 
[bar] 
[bar] > logistics-client@0.0.0 foo:bar
[bar] > node block.js
[bar] 
[baz] [
[baz]   'C:\\Program Files\\nodejs\\node.exe',
[baz]   'C:\\Users\\cepharum\\PhpstormProjects\\UID\\Logistics\\WebClient\\Source\\UiNew\\log.js',
[baz]   '--tags',
[baz]   '\\@foo'
[baz] ]
[baz] npm run foo:baz -- --tags \@foo exited with code 0
--> Sending SIGTERM to other processes..
[bar] npm run foo:bar exited with code 1

The @ character still ends up escaped.

I've also tried using {*} on invoking concurrently. So, the script in package.json is now:

"foo": "concurrently -k -n \"bar,baz\" -P npm:foo:bar \"npm:foo:baz -- {*}\"",

Invoking as before prevents the escaping, but yields a different issue:

$ npm run foo -- -- --tags @foo

> logistics-client@0.0.0 foo
> concurrently -k -n "bar,baz" -P npm:foo:bar "npm:foo:baz -- {*}" -- --tags @foo

[baz] 
[baz] > logistics-client@0.0.0 foo:baz
[baz] > node log.js '--tags @foo'
[baz]
[bar]
[bar] > logistics-client@0.0.0 foo:bar
[bar] > node block.js
[bar]
[baz] [
[baz]   'C:\\Program Files\\nodejs\\node.exe',
[baz]   'C:\\Users\\cepharum\\PhpstormProjects\\UID\\Logistics\\WebClient\\Source\\UiNew\\log.js',
[baz]   "'--tags",
[baz]   "@foo'"
[baz] ]
[baz] npm run foo:baz -- '--tags @foo' exited with code 0
--> Sending SIGTERM to other processes..
[bar] npm run foo:bar exited with code 1

So, the {*} seems to wrap all additional arguments in a single pair quotes. This may be intentional, but it definitely doesn't help here:

$ npm run foo -- -- --tags @foo --debug-on-fail

> logistics-client@0.0.0 foo
> concurrently -k -n "bar,baz" -P npm:foo:bar "npm:foo:baz -- {*}" -- --tags @foo --debug-on-fail

[baz] 
[baz] > logistics-client@0.0.0 foo:baz
[baz] > node log.js '--tags @foo --debug-on-fail'
[baz]
[bar]
[bar] > logistics-client@0.0.0 foo:bar
[bar] > node block.js
[bar]
[baz] [
[baz]   'C:\\Program Files\\nodejs\\node.exe',
[baz]   'C:\\Users\\cepharum\\PhpstormProjects\\UID\\Logistics\\WebClient\\Source\\UiNew\\log.js',
[baz]   "'--tags",
[baz]   '@foo',
[baz]   "--debug-on-fail'"
[baz] ]
[baz] npm run foo:baz -- '--tags @foo --debug-on-fail' exited with code 0
--> Sending SIGTERM to other processes..
[bar] npm run foo:bar exited with code 1

Run the Windows reproduction from the package.json scripts using block.js and log.js, first comparing --passthrough-arguments with {*} and inspecting the resulting process.argv output. Trace the argument handling for the concurrently CLI entry point; done means pass-through arguments reach the child process without unwanted escaping or grouping.