Test command for PHP Language Server returns true when lsp-clients-php-server-command is nil.

[AlexanderSeto]

Thank you for the bug report

• I am using the latest version of lsp-mode related packages.
• I checked FAQ and Troubleshooting sections
• You may also try reproduce the issue using clean environment using the following command: M-x lsp-start-plain

Bug description

The test command for the PHP Language Server (php-ls) returns true when lsp-clients-php-server-command is nil.

When invoking lsp for the first time, lsp--filter-clients will check all available clients for lsp--supports-buffer? and server-binary-present?. When it checks php-ls, server-binary-present? will rely on the output of the test-command passed to lsp-stdio-connection. I

Since the test-command runs before the command, lsp-clients-php-server-command is never set. This means that it will fail the first condition here, and then will return t.

This results in php-ls appearing in the list of available servers despite not being installed. All the other servers (save for phpactor) have a higher priority. So php-ls will only be run if either no other server is installed, or if only phpactor is installed.

---

Subsequent invocations of lsp will behave as expected, since the command for php-ls sets lsp-clients-php-server-command.

Steps to reproduce

1. Fresh emacs
2. Don't install Intelephense or Serenata
3. Don't install PHP Language Server
4. Install phpactor(Optional)
5. Open a php file

Expected behavior

php-ls shouldn't appear in the available servers list if the PHP language server isn't installed.

Which Language Server did you use?

lsp-php

OS

MacOS

Error callstack

First Invocation:
Command "semgrep lsp" is not present on the path.                                                                                                                                                                                             
Command "/usr/local/bin/phpactor language-server" is present on the path.                                                                                                                                                                     
Command "serenata.phar -u 0" is not present on the path.                                                                                                                                                                                      
Command "semgrep lsp" is not present on the path.                                                                                                                                                                                             
Command "/usr/local/bin/phpactor language-server" is present on the path.                                                                                                                                                                     
Command "serenata.phar -u 0" is not present on the path.                                                                                                                                                                                      
Found the following clients for [php file]: (server-id phpactor, priority -4), (server-id php-ls, priority -3)                                                                                     
The following clients were selected based on priority: (server-id php-ls, priority -3)


Second Invocation:                                                                                                                                        
Command "semgrep lsp" is not present on the path.                                                                                                                                                                                             
Command "/usr/local/bin/phpactor language-server" is present on the path.                                                                                                                                                                     
Command "serenata.phar -u 0" is not present on the path.                                                                                                                                                                                      
[home dir]/.composer/vendor/felixfbecker/language-server/bin/php-language-server.php is not present.                                                                                                                                        
Command "semgrep lsp" is not present on the path.                                                                                                                                                                                             
Command "/usr/local/bin/phpactor language-server" is present on the path.                                                                                                                                                                     
Command "serenata.phar -u 0" is not present on the path.                                                                                                                                                                                      
[home dir]/.composer/vendor/felixfbecker/language-server/bin/php-language-server.php is not present.                                                                                                                                        
Found the following clients for [php file]: (server-id phpactor, priority -4)                                                                                                                      
The following clients were selected based on priority: (server-id phpactor, priority -4)                                                                                                                                                      
Creating watchers for following 25 folders:

Anything else?

I believe I've identified the issue and will be submitting a PR shortly.