[Language server] Signature Help feature doesn't work with "(" character

[SkorikSergey]

Reproduction Steps:

1. Create and start workspace from PHP stack with "web-php-simple" project.
2. Open index.php file and change text to:

<?php
function sum($x, $y) {
    return $x + $y;
}
echo "14 + 16 = " . sum(14,16)
?>

3. Create a new line in position 6 and type sum(.

Expected behavior:
Hover with (mixed $x, mixed $y) message appeared.

Observed behavior:
Nothing changes. The feature will work only with "," character.

Che version: 6.10.0
OS and version: Fedora 28
Language servers that supported this feature: PHP, Python, Clang, Type Script, Golang, C#.

Additional information:

• Problem can be reliably reproduced, doesn't happen randomly: [Yes]
• See the attachment:

Screencast:

Screenshot:
Hover will appear only after "," character.

[tsmaeder]

There is no code in the signature help provider that hard codes any particular trigger character. Most likely, the php language server does not provide "(" as a trigger character. That would be a problem with the PHP language server outside of our control.

[SkorikSergey]

[musienko-maxim]

So, as we've just clarified this feature works as well with Ctrl+P key. And we should implement this in our tests. But this one also is invoked by (( and , symbols. And this may be bring potential conflicts. We have to think how it should work together.
Also after invocation of ( symbol we have unexpected exceptions in the dev-machine console under TypeScript LS. So, we are going to check this under other language servers and report about this in this issue.

• The unexpected exceptions are actual for TypeScript LS only.

[dkuleshov]

ci-test