Bug 1636797 - In `hash.py`, enumerate files from the VCS rather than searching the filesystem directly r=ahal

This resolves a long-standing issue in development where `mach artifact` (and therefore `mach bootstrap`) would fail unpredictably if you had dirty, but ignored, files in your checkout. Resolving this problem often required unwieldy `hg purge`/`git ignore` incantations that are easy to get wrong.

This patch addresses the problem by doing what we "should" have been doing all along, and consulting the VCS to list tracked files rather than listing EVERY file on disk and applying heuristics to determine whether they should be included in the hash.

Differential Revision: https://phabricator.services.mozilla.com/D86780

config/check_js_msg_encoding.py

@@ -54,11 +54,10 @@ def check_files():
     with get_repository_from_env() as repo:
         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(os.path.join(root, filename)):
-                        result = False
+        for filename, _ in repo.get_tracked_files_finder().find('**/*.msg'):
+            if filename not in ignore_files:
+                if not check_single_file(os.path.join(root, filename)):
+                    result = False
 
     return result
 

python/mozbuild/mozpack/files.py

@@ -4,6 +4,7 @@
 
 from __future__ import absolute_import, print_function, unicode_literals
 
+import bisect
 import codecs
 import errno
 import inspect
@@ -15,11 +16,12 @@ import stat
 import subprocess
 import uuid
 import mozbuild.makeutil as makeutil
-from itertools import chain
+from itertools import chain, takewhile
 from mozbuild.preprocessor import Preprocessor
 from mozbuild.util import (
     FileAvoidWrite,
     ensure_unicode,
+    memoize
 )
 from mozpack.executables import (
     is_executable,
@@ -1238,3 +1240,39 @@ class MercurialRevisionFinder(BaseFinder):
             self._files[path] = f
 
         return f
+
+
+class FileListFinder(BaseFinder):
+    """Finder for a literal list of file names."""
+
+    def __init__(self, files):
+        """files must be a sorted list."""
+        self._files = files
+
+    @memoize
+    def _match(self, pattern):
+        """Return a sorted list of all files matching the given pattern."""
+        # We don't use the utility _find_helper method because it's not tuned
+        # for performance in the way that we would like this class to be. That's
+        # a possible avenue for refactoring here.
+        ret = []
+        # We do this as an optimization to figure out where in the sorted list
+        # to search and where to stop searching.
+        components = pattern.split('/')
+        prefix = '/'.join(takewhile(lambda s: '*' not in s, components))
+        start = bisect.bisect_left(self._files, prefix)
+        for i in six.moves.range(start, len(self._files)):
+            f = self._files[i]
+            if not f.startswith(prefix):
+                break
+            # Skip hidden files while scanning.
+            if '/.' in f[len(prefix):]:
+                continue
+            if mozpath.match(f, pattern):
+                ret.append(f)
+        return ret
+
+    def find(self, pattern):
+        pattern = pattern.strip('/')
+        for path in self._match(pattern):
+            yield path, File(path)

python/mozversioncontrol/mozversioncontrol/__init__.py

@@ -14,6 +14,7 @@ import sys
 
 from mozbuild.util import ensure_subprocess_env
 from mozfile import which
+from mozpack.files import FileListFinder
 
 
 class MissingVCSTool(Exception):
@@ -216,8 +217,14 @@ class Repository(object):
         '''
 
     @abc.abstractmethod
-    def get_files_in_working_directory(self):
-        """Obtain a list of managed files in the working directory."""
+    def get_tracked_files_finder(self):
+        """Obtain a mozpack.files.BaseFinder of managed files in the working
+        directory.
+
+        The Finder will have its list of all files in the repo cached for its
+        entire lifetime, so operations on the Finder will not track with, for
+        example, commits to the repo during the Finder's lifetime.
+        """
 
     @abc.abstractmethod
     def working_directory_clean(self, untracked=False, ignored=False):
@@ -419,10 +426,11 @@ class HgRepository(Repository):
             return
         self._run('forget', *paths)
 
-    def get_files_in_working_directory(self):
+    def get_tracked_files_finder(self):
         # Can return backslashes on Windows. Normalize to forward slashes.
-        return list(p.replace('\\', '/') for p in
-                    self._run(b'files', b'-0').split('\0') if p)
+        files = list(p.replace('\\', '/') for p in
+                     self._run(b'files', b'-0').split('\0') if p)
+        return FileListFinder(files)
 
     def working_directory_clean(self, untracked=False, ignored=False):
         args = ['status', '--modified', '--added', '--removed',
@@ -549,8 +557,9 @@ class GitRepository(Repository):
             return
         self._run('reset', *paths)
 
-    def get_files_in_working_directory(self):
-        return [p for p in self._run('ls-files', '-z').split('\0') if p]
+    def get_tracked_files_finder(self):
+        files = [p for p in self._run('ls-files', '-z').split('\0') if p]
+        return FileListFinder(files)
 
     def working_directory_clean(self, untracked=False, ignored=False):
         args = ['status', '--porcelain']

taskcluster/taskgraph/util/hash.py

@@ -4,8 +4,8 @@
 
 from __future__ import absolute_import, print_function, unicode_literals
 from mozbuild.util import memoize
-from mozpack.files import FileFinder
 import mozpack.path as mozpath
+from mozversioncontrol import get_repository_object
 import hashlib
 import io
 import six
@@ -21,6 +21,11 @@ def hash_path(path):
         return hashlib.sha256(fh.read()).hexdigest()
 
 
+@memoize
+def get_file_finder(base_path):
+    return get_repository_object(base_path).get_tracked_files_finder()
+
+
 def hash_paths(base_path, patterns):
     """
     Give a list of path patterns, return a digest of the contents of all
@@ -30,7 +35,7 @@ def hash_paths(base_path, patterns):
     Each file is hashed. The list of all hashes and file paths is then
     itself hashed to produce the result.
     """
-    finder = FileFinder(base_path)
+    finder = get_file_finder(base_path)
     h = hashlib.sha256()
     files = {}
     for pattern in patterns: