test: make a test path-independent

[vsemozhetbyt]

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• commit message follows commit guidelines

Affected core subsystem(s)

test, child_process

This is the first step to fix the #12773.

I've decided to start from the most whimsical one (section 4 in the #12773): parallel/test-spawn-cmd-named-pipe.js fails if spaces exist both in node.exe and the test paths. If there are no spaces or there are spaces only in one of the paths (either), the test passes.

If I get it right, the cause is the very complicated rules for cmd.exe command line syntax concerning spaces and quotes: see "Quote Characters in a command" here and "Examples:" here.

The fixed test passes with all 4 paths variants (spaceless + spaceless, spacy + spaceless, spaceless + spacy, and spacy + spacy).

Please, test in more environments and propose better fixes if you have some)

cc @nodejs/testing, @nodejs/platform-windows, @bnoordhuis, @cjihrig

[vsemozhetbyt]

CI: https://ci.nodejs.org/job/node-test-pull-request/7983/

[vsemozhetbyt]

The test runs only on Windows and Windows is OK in CI. One Linux fail must be irrelevant.

[cjihrig]

If we go this route, the test may need to be renamed since it no longer uses spawn().

[cjihrig]

Would quoting the args and specifying the shell work with spawn()?

[vsemozhetbyt]

I've tried and failed. It seems the args are re-quoted internally in an inappropriate way for this case. But I may miss some variants. Can anybody else test?

[cjihrig]

Does windowsVerbatimArguments make a difference?

[vsemozhetbyt]

Is this documented? I can't find.

[vsemozhetbyt]

I've found out a way with spawn():

  const args = ['/c', `""${process.execPath}"`, `"${__filename}"`, 'child',
                '<', stdinPipeName, '>', `${stdoutPipeName}"`];

  const child = spawn(comspec, args, { shell: true });

But it seems strange. And we execute cmd.exe with cmd.exe first, if I get this right. Is this way better?

[cjihrig]

windowsVerbatimArguments is not documented. See

node/lib/child_process.js

Lines 424 to 428 in cfe7b34

	if (process.platform === 'win32') {
	file = typeof options.shell === 'string' ? options.shell :
	process.env.comspec || 'cmd.exe';
	args = ['/d', '/s', '/c', '"' + command + '"'];
	options.windowsVerbatimArguments = true;

.

When you run exec() or spawn() with shell: true, this code path is hit. It's probably what you're looking for.

[vsemozhetbyt]

Another way:

  const args =
    [`"${__filename}"`, 'child', '<', stdinPipeName, '>', stdoutPipeName];

  const child = spawn(`"${process.execPath}"`, args, { shell: true });

Slightly better maybe than the previous one.

[vsemozhetbyt]

This does not work:

  const args = ['/c', `"${process.execPath}"`, `"${__filename}"`, 'child',
                '<', stdinPipeName, '>', stdoutPipeName];

  const child = spawn(comspec, args,
                      { shell: true, windowsVerbatimArguments: true });

Should I prefer one of the beforementioned variants with spawn()?

[cjihrig]

The variant in #12945 (comment) seems reasonable enough.

[vsemozhetbyt]

@cjihrig Done. CI: https://ci.nodejs.org/job/node-test-pull-request/7995/

[refack]

LGTM if CI is green

[refack]

@vsemozhetbyt you could update the first comment, since you eventually found a way to use spawn
IMHO you could also change title to something simpler like: test: make test path-robust or path agnostic

[cjihrig]

LGTM pending CI

[vsemozhetbyt]

@refack I've unified with the #12812

[vsemozhetbyt]

Windows CI is green.

[vsemozhetbyt]

Landed in 529e4f2