Bug 1361172 - Rewrite code for finding files in VCS checkout; r=glandium

We're getting an intermittent failure running `hg manifest` in CI. I
have no clue why.

What I do know is that we now have the mozversioncontrol Python package
for containing utility code for interacting with version control. It is
slightly more robust and I'm willing to support it more than I am
check_utils.py.

This commit adds a new API to our abstract repository class to obtain the
files in the working directory by querying version control.

Since I suspect cwd was coming into play in automation, I've also
added a utility function to mozversioncontrol to attempt to find
a version control checkout from the current working directory. It
simply traces ancestor paths looking for a .hg or .git directory.

Finally, I've ported all callers of the now-deleted API to the new
one. The old code had some "../.." paths in it, meaning it only
worked when cwd was just right. Since we resolve the absolute path
to the checkout and store it on the repo object, I've updated the
code so it should work no matter what cwd is as long as a repo can
be found. I'm not 100% confident I found all consumers assuming cwd.
But it's a start.

I'm not 100% confident this will fix the intermittent issues in CI. But
at least we should get a better error message and at least we'll be
running less hacky code.

MozReview-Commit-ID: AmCraHXcTEX

--HG--
extra : rebase_source : 815ae369776577ad374333920fd645d412a55148

config/check_js_msg_encoding.py

@@ -13,7 +13,9 @@ from __future__ import print_function
 
 import os
 import sys
-from check_utils import get_all_toplevel_filenames
+
+from mozversioncontrol import get_repository_from_env
+
 
 scriptname = os.path.basename(__file__);
 expected_encoding = 'ascii'
@@ -45,10 +47,13 @@ def check_single_file(filename):
 def check_files():
     result = True
 
-    for filename in get_all_toplevel_filenames():
+    repo = get_repository_from_env()
+    root = repo.path
+
+    for filename in repo.get_files_in_working_directory():
         if filename.endswith('.msg'):
             if filename not in ignore_files:
-                if not check_single_file(filename):
+                if not check_single_file(os.path.join(root, filename)):
                     result = False
 
     return result

config/check_macroassembler_style.py

@@ -25,9 +25,10 @@ from __future__ import print_function
 import difflib
 import os
 import re
-import subprocess
 import sys
-from check_utils import get_all_toplevel_filenames
+
+from mozversioncontrol import get_repository_from_env
+
 
 architecture_independent = set([ 'generic' ])
 all_architecture_names = set([ 'x86', 'x64', 'arm', 'arm64', 'mips32', 'mips64' ])
@@ -131,7 +132,7 @@ def get_macroassembler_definitions(filename):
     code_section = False
     lines = ''
     signatures = []
-    with open(os.path.join('../..', filename)) as f:
+    with open(filename) as f:
         for line in f:
             if '//{{{ check_macroassembler_style' in line:
                 style_section = True
@@ -171,7 +172,7 @@ def get_macroassembler_declaration(filename):
     style_section = False
     lines = ''
     signatures = []
-    with open(os.path.join('../..', filename)) as f:
+    with open(filename) as f:
         for line in f:
             if '//{{{ check_macroassembler_style' in line:
                 style_section = True
@@ -238,13 +239,17 @@ def check_style():
     # We infer from each file the signature of each MacroAssembler function.
     defs = dict()       # type: dict(signature => ['x86', 'x64'])
 
+    repo = get_repository_from_env()
+
     # Select the appropriate files.
-    for filename in get_all_toplevel_filenames():
+    for filename in repo.get_files_in_working_directory():
         if not filename.startswith('js/src/jit/'):
             continue
         if 'MacroAssembler' not in filename:
             continue
 
+        filename = os.path.join(repo.path, filename)
+
         if filename.endswith('MacroAssembler.h'):
             decls = append_signatures(decls, get_macroassembler_declaration(filename))
         else:

config/check_spidermonkey_style.py

@@ -40,10 +40,10 @@ from __future__ import print_function
 import difflib
 import os
 import re
-import subprocess
 import sys
-import traceback
+
-from check_utils import get_all_toplevel_filenames
+from mozversioncontrol import get_repository_from_env
+
 
 # We don't bother checking files in these directories, because they're (a) auxiliary or (b)
 # imported code that doesn't follow our coding style.
@@ -249,8 +249,10 @@ def check_style():
     non_js_inclnames = set()        # type: set(inclname)
     js_names = dict()               # type: dict(filename, inclname)
 
+    repo = get_repository_from_env()
+
     # Select the appropriate files.
-    for filename in get_all_toplevel_filenames():
+    for filename in repo.get_files_in_working_directory():
         for non_js_dir in non_js_dirnames:
             if filename.startswith(non_js_dir) and filename.endswith('.h'):
                 inclname = 'mozilla/' + filename.split('/')[-1]
@@ -285,7 +287,7 @@ def check_style():
 
             # This script is run in js/src/, so prepend '../../' to get to the root of the Mozilla
             # source tree.
-            with open(os.path.join('../..', filename)) as f:
+            with open(os.path.join(repo.path, filename)) as f:
                 do_file(filename, inclname, file_kind, f, all_inclnames, included_h_inclnames)
 
         edges[inclname] = included_h_inclnames

config/check_utils.py

@@ -1,31 +0,0 @@
-# vim: set ts=8 sts=4 et sw=4 tw=99:
-# This Source Code Form is subject to the terms of the Mozilla Public
-# License, v. 2.0. If a copy of the MPL was not distributed with this
-# file, You can obtain one at http://mozilla.org/MPL/2.0/.
-
-import subprocess
-
-def get_all_toplevel_filenames():
-    '''Get a list of all the files in the (Mercurial or Git) repository.'''
-    failed_cmds = []
-    try:
-        cmd = ['hg', 'manifest', '-q']
-        all_filenames = subprocess.check_output(cmd, universal_newlines=True,
-                                                stderr=subprocess.PIPE).split('\n')
-        return all_filenames
-    except:
-        failed_cmds.append(cmd)
-
-    try:
-        # Get the relative path to the top-level directory.
-        cmd = ['git', 'rev-parse', '--show-cdup']
-        top_level = subprocess.check_output(cmd, universal_newlines=True,
-                                                stderr=subprocess.PIPE).split('\n')[0]
-        cmd = ['git', 'ls-files', '--full-name', top_level]
-        all_filenames = subprocess.check_output(cmd, universal_newlines=True,
-                                                stderr=subprocess.PIPE).split('\n')
-        return all_filenames
-    except:
-        failed_cmds.append(cmd)
-
-    raise Exception('failed to run any of the repo manifest commands', failed_cmds)

python/mozversioncontrol/mozversioncontrol/__init__.py

@@ -76,6 +76,11 @@ class Repository(object):
         '''
         raise NotImplementedError
 
+    def get_files_in_working_directory(self):
+        """Obtain a list of managed files in the working directory."""
+        raise NotImplementedError
+
+
 class HgRepository(Repository):
     '''An implementation of `Repository` for Mercurial repositories.'''
     def __init__(self, path):
@@ -99,6 +104,12 @@ class HgRepository(Repository):
     def forget_add_remove_files(self, path):
         self._run('forget', path)
 
+    def get_files_in_working_directory(self):
+        # Can return backslashes on Windows. Normalize to forward slashes.
+        return list(p.replace('\\', '/') for p in
+                    self._run('files', '-0').split('\0'))
+
+
 class GitRepository(Repository):
     '''An implementation of `Repository` for Git repositories.'''
     def __init__(self, path):
@@ -116,6 +127,14 @@ class GitRepository(Repository):
     def forget_add_remove_files(self, path):
         self._run('reset', path)
 
+    def get_files_in_working_directory(self):
+        return self._run('ls-files', '-z').split('\0')
+
+
+class InvalidRepoPath(Exception):
+    """Represents a failure to find a VCS repo at a specified path."""
+
+
 def get_repository_object(path):
     '''Get a repository object for the repository at `path`.
     If `path` is not a known VCS repository, raise an exception.
@@ -125,4 +144,24 @@ def get_repository_object(path):
     elif os.path.exists(os.path.join(path, '.git')):
         return GitRepository(path)
     else:
-        raise Exception('Unknown VCS, or not a source checkout: %s' % path)
+        raise InvalidRepoPath('Unknown VCS, or not a source checkout: %s' %
+                              path)
+
+
+def get_repository_from_env():
+    """Obtain a repository object by looking at the environment."""
+    def ancestors(path):
+        while path:
+            yield path
+            path, child = os.path.split(path)
+            if child == '':
+                break
+
+    for path in ancestors(os.getcwd()):
+        try:
+            return get_repository_object(path)
+        except InvalidRepoPath:
+            continue
+
+    raise Exception('Could not find Mercurial or Git checkout for %s' %
+                    os.getcwd())