bug #34848 [Process] change the syntax of portable command lines (nic…

…olas-grekas)

This PR was merged into the 4.4 branch.

Discussion
----------

[Process] change the syntax of portable command lines

| Q             | A
| ------------- | ---
| Branch?       | 4.4
| Bug fix?      | yes
| New feature?  | no
| Deprecations? | no
| Tickets       | Fix #34838
| License       | MIT
| Doc PR        | symfony/symfony-docs#12772

An alternative to #34845

Right now, portable command lines use `"$FOO"` for placeholders.
But because we validate that a corresponding variable exists before running the command, this fails with `Command line is missing a value for key "$FOO"` when `FOO` is not defined.

This PR proposes to use `"${:FOO}"` instead. The difference with the previous syntax is that this cannot collide with existing shell scripts as it is invalid for them.

When this is merged, we'll have to update https://symfony.com/blog/new-in-symfony-4-1-prepared-commands too.

Commits
-------

3c7b775 [Process] change the syntax of portable prepared command lines

src/Symfony/Component/Process/Process.php

@@ -1643,12 +1643,12 @@ private function escapeArgument(?string $argument): string
 
     private function replacePlaceholders(string $commandline, array $env)
     {
-        return preg_replace_callback('/"\$([_a-zA-Z]++[_a-zA-Z0-9]*+)"/', function ($matches) use ($commandline, $env) {
+        return preg_replace_callback('/"\$\{:([_a-zA-Z]++[_a-zA-Z0-9]*+)\}"/', function ($matches) use ($commandline, $env) {
             if (!isset($env[$matches[1]]) || false === $env[$matches[1]]) {
-                throw new InvalidArgumentException(sprintf('Command line is missing a value for key %s: %s.', $matches[0], $commandline));
+                throw new InvalidArgumentException(sprintf('Command line is missing a value for parameter "%s": %s.', $matches[1], $commandline));
             }
 
-            return '\\' === \DIRECTORY_SEPARATOR ? $this->escapeArgument($env[$matches[1]]) : $matches[0];
+            return $this->escapeArgument($env[$matches[1]]);
         }, $commandline);
     }
 

src/Symfony/Component/Process/Tests/ProcessTest.php

@@ -1463,23 +1463,23 @@ public function provideEscapeArgument()
 
     public function testPreparedCommand()
     {
-        $p = Process::fromShellCommandline('echo "$abc"DEF');
+        $p = Process::fromShellCommandline('echo "${:abc}"DEF');
         $p->run(null, ['abc' => 'ABC']);
 
         $this->assertSame('ABCDEF', rtrim($p->getOutput()));
     }
 
     public function testPreparedCommandMulti()
     {
-        $p = Process::fromShellCommandline('echo "$abc""$def"');
+        $p = Process::fromShellCommandline('echo "${:abc}""${:def}"');
         $p->run(null, ['abc' => 'ABC', 'def' => 'DEF']);
 
         $this->assertSame('ABCDEF', rtrim($p->getOutput()));
     }
 
     public function testPreparedCommandWithQuoteInIt()
     {
-        $p = Process::fromShellCommandline('php -r "$code" "$def"');
+        $p = Process::fromShellCommandline('php -r "${:code}" "${:def}"');
         $p->run(null, ['code' => 'echo $argv[1];', 'def' => '"DEF"']);
 
         $this->assertSame('"DEF"', rtrim($p->getOutput()));
@@ -1488,16 +1488,16 @@ public function testPreparedCommandWithQuoteInIt()
     public function testPreparedCommandWithMissingValue()
     {
         $this->expectException('Symfony\Component\Process\Exception\InvalidArgumentException');
-        $this->expectExceptionMessage('Command line is missing a value for key "$abc": echo "$abc".');
-        $p = Process::fromShellCommandline('echo "$abc"');
+        $this->expectExceptionMessage('Command line is missing a value for parameter "abc": echo "${:abc}".');
+        $p = Process::fromShellCommandline('echo "${:abc}"');
         $p->run(null, ['bcd' => 'BCD']);
     }
 
     public function testPreparedCommandWithNoValues()
     {
         $this->expectException('Symfony\Component\Process\Exception\InvalidArgumentException');
-        $this->expectExceptionMessage('Command line is missing a value for key "$abc": echo "$abc".');
-        $p = Process::fromShellCommandline('echo "$abc"');
+        $this->expectExceptionMessage('Command line is missing a value for parameter "abc": echo "${:abc}".');
+        $p = Process::fromShellCommandline('echo "${:abc}"');
         $p->run(null, []);
     }