[Process] A command containing slashes instead of backslashes should be quoted on Windows

[maryo]

Q	A
Bug report?	yes
Feature request?	no
BC Break report?	yes
RFC?	no
Symfony version	3.3

On Windows it is possible to use / directory separator instead of \ to run a command inside CLI. But to be able to run such a command the path needs to be quoted.

I am using SF 3.3 now but I guess this commit caused the BC break which is merged to many versions.
3779f3f#diff-bfb5d7f8e7485d053a135b3692e8a0ca

Thus also the example in this test is not correct. It would not work on Windows.
https://github.com/symfony/symfony/blob/master/src/Symfony/Component/Process/Tests/ProcessBuilderTest.php#L94

D:\Program Files>php\php -r "echo 'hello';"
hello
D:\Program Files>php/php -r "echo 'hello';"
Could not open input file: /php

D:\Program Files>"php/php" -r "echo 'hello';"
hello
D:\Program Files>

[nicolas-grekas]

Can you provide a reproducer test that we could add to the test suite?
The linked commit is applicable to non-Windiws OSes so that's really strange that you found it to have introduced the issue...

[maryo]

@nicolas-grekas You're right. I missed the last return inside the Windows condition and the ProcessUtils::escapeArgument is actually not used anymore since SF 3.3. That's the problem. OK, I'll send a PR in few minutes.