Add PHP language support

pre_commit/languages/all.py

@@ -2,6 +2,7 @@ from __future__ import unicode_literals
 
 from pre_commit.languages import node
 from pre_commit.languages import pcre
+from pre_commit.languages import php
 from pre_commit.languages import python
 from pre_commit.languages import ruby
 from pre_commit.languages import script
@@ -42,6 +43,7 @@ from pre_commit.languages import system
 languages = {
     'node': node,
     'pcre': pcre,
+    'php': php,
     'python': python,
     'ruby': ruby,
     'script': script,

pre_commit/languages/php.py

@@ -0,0 +1,131 @@
+from __future__ import unicode_literals
+
+import contextlib
+import json
+import os
+
+from pre_commit.envcontext import envcontext
+from pre_commit.envcontext import Var
+from pre_commit.languages import helpers
+from pre_commit.util import clean_path_on_failure
+from pre_commit.util import resource_filename
+from pre_commit.xargs import xargs
+
+
+ENVIRONMENT_DIR = 'virtphpenv'
+VIRT_PHP_PATH = resource_filename('virtphp.phar')
+# It's currently impossible to move this file out of homedir
+VIRT_PHP_ENVIRONMENTS = os.path.join(
+    os.path.expanduser('~'),
+    '.virtphp',
+    'environments.json'
+)
+
+
+def get_env_patch(venv, language_version):
+    patches = (
+        ('VIRTPHP_COMPOSER_GLOBAL', '1'),
+        ('COMPOSER_HOME', os.path.join(venv, 'composer')),
+        ('PHP_INI_SCAN_DIR', os.path.join(venv, 'etc', 'php')),
+        ('PATH', (
+            os.path.join(venv, 'bin'), os.pathsep,
+            os.path.join(venv, 'vendor/bin'), os.pathsep, Var('PATH')
+        ))
+    )
+
+    return patches
+
+
+@contextlib.contextmanager
+def in_env(repo_cmd_runner, language_version):
+    envdir = os.path.join(
+        repo_cmd_runner.prefix_dir,
+        helpers.environment_dir(ENVIRONMENT_DIR, language_version),
+    )
+
+    with envcontext(get_env_patch(envdir, language_version)):
+        yield
+
+
+@contextlib.contextmanager
+def cleanup_environment_on_failure(repo_cmd_runner, directory):
+    with clean_path_on_failure(repo_cmd_runner.path(directory)):
+        with clean_virtphp_environment_on_failure(directory):
+            yield
+
+
+@contextlib.contextmanager
+def clean_virtphp_environment_on_failure(directory):
+    """VirtPHP keeps an environments.json file that lists the envs that it
+    thinks exists, and it will fail to install them if it thinks that one
+    exists, even if it does not.
+    This file looks like:
+    {
+        "virtenv-default": {}
+    }
+    """
+    try:
+        yield
+    except BaseException:
+        if os.path.exists(VIRT_PHP_ENVIRONMENTS):
+            with open(VIRT_PHP_ENVIRONMENTS, 'r+') as f:
+                environments = json.loads(f.read())
+                environments = {
+                    environment_key: environment_config
+                    for environment_key, environment_config
+                    in environments.items() if environment_key != directory
+                }
+                f.seek(0)
+                f.write(json.dumps(environments))
+                f.truncate()
+
+        raise
+
+
+def install_environment(
+        repo_cmd_runner,
+        version='default',
+        additional_dependencies=(),
+):
+    additional_dependencies = tuple(additional_dependencies)
+    directory = helpers.environment_dir(ENVIRONMENT_DIR, version)
+
+    with cleanup_environment_on_failure(repo_cmd_runner, directory):
+        virtphp_env_command = [
+            'php', VIRT_PHP_PATH, 'create',
+            '--install-path', repo_cmd_runner.prefix_dir[:-1],
+            directory
+        ]
+
+        if version != 'default':
+            # TODO: Not sure what the best choice is here. There's doesn't seem
+            # to be a canonical way to keep multiple php versions around.
+            # It's Different per OS, package manager, etc. language_version
+            # as a php bin directory (as shown here) might be sanest?
+            virtphp_env_command.extend(
+                ['--php-bin-dir', os.path.realpath(version)]
+            )
+
+        repo_cmd_runner.run(virtphp_env_command, cwd='/')
+        with in_env(repo_cmd_runner, version):
+            helpers.run_setup_cmd(
+                repo_cmd_runner,
+                # There's no way to install platform requirements out of band
+                # as we're creating the php environment via pre-commit, nor is
+                # there a generalized way to install them. If hooks
+                # need platform requirements, they should install it themselves
+                # in a pre-install composer hook. Therefore, we ignore
+                # platform requirements for composer installation.
+                (
+                    'composer',
+                    'install',
+                    '--ignore-platform-reqs'
+                ) + additional_dependencies
+            )
+
+
+def run_hook(repo_cmd_runner, hook, file_args):
+    return xargs(
+        (repo_cmd_runner.prefix_dir + hook['entry'],) + tuple(hook['args']),
+        file_args,
+    )