Add emacs-friendly headers. Address other comments.

BUILD.bazel

@@ -1,3 +1,5 @@
+# -*- python -*-
+
 package(default_visibility = ["//visibility:public"])
 
 alias(

src/bazel_external_data/BUILD.bazel

@@ -1,3 +1,9 @@
+# -*- python -*-
+
+# Use relative package path, as `py_library` does not like absolute package
+# paths. This ensures that `//src` is added to `PYTHONPATH`.
+imports = [".."]
+
 # @note 'core' has no backends present.
 py_library(
     name = "core",
@@ -7,7 +13,7 @@ py_library(
         "util.py",
         "hashes.py",
     ],
-    imports = [".."],
+    imports = imports,
     visibility = ["//visibility:public"],
 )
 
@@ -22,7 +28,7 @@ py_library(
         ":core",
         "//src/bazel_external_data/backends",
     ],
-    imports = [".."],
+    imports = imports,
     visibility = ["//visibility:public"],
 )
 

src/bazel_external_data/backends/BUILD.bazel

@@ -1,3 +1,7 @@
+# -*- python -*-
+
+# Use relative package path, as `py_library` does not like absolute package
+# paths. This ensures that `//src` is added to `PYTHONPATH`.
 imports = ["../.."]
 
 py_library(

src/bazel_external_data/config_helpers.py

@@ -12,8 +12,8 @@
 from bazel_external_data import util
 
 
-def guess_start_dir(filepath):
-    """Returns the directory of a file, or the directory if passed directly."""
+def _resolve_dir(filepath):
+    # Returns the directory of a file, or the directory if passed directly.
     if os.path.isdir(filepath):
         return filepath
     else:
@@ -37,7 +37,7 @@ def sentinel_check(filepath):
         else:
             return False
 
-    start_dir = guess_start_dir(guess_filepath)
+    start_dir = _resolve_dir(guess_filepath)
     root_file = util.find_file_sentinel(start_dir, sentinel, sentinel_check)
     if root_file is None:
         hint = ""

src/bazel_external_data/util.py

@@ -72,7 +72,7 @@ def find_file_sentinel(start_dir, sentinel_file,
     """Finds a sentinel given a check. """
     cur_dir = start_dir
     assert len(cur_dir) > 0
-    for i in xrange(max_depth):
+    for _ in xrange(max_depth):
         assert os.path.isdir(cur_dir)
         test_path = os.path.join(cur_dir, sentinel_file)
         if sentinel_check(test_path):

test/BUILD.bazel

@@ -1,3 +1,5 @@
+# -*- python -*-
+
 sh_test(
     name = "workflows_test",
     srcs = ["workflows_test.sh"],

test/bazel_pkg_advanced_test/BUILD.bazel

@@ -1,3 +1,5 @@
+# -*- python -*-
+
 filegroup(
     name = "external_data_sentinel",
     srcs = [":.external_data.yml"],

test/bazel_pkg_advanced_test/data/BUILD.bazel

@@ -1,3 +1,5 @@
+# -*- python -*-
+
 load("//tools:external_data.bzl",
     "external_data",
     "external_data_group",

test/bazel_pkg_advanced_test/tools/BUILD.bazel

@@ -1,3 +1,5 @@
+# -*- python -*-
+
 # Do not use user's configuration.
 exports_files(
     srcs = [

test/bazel_pkg_downstream_test/BUILD.bazel

@@ -1,3 +1,5 @@
+# -*- python -*-
+
 py_test(
     name = "test_basics",
     srcs = ["test_basics.py"],

test/bazel_pkg_test/BUILD.bazel

@@ -1,3 +1,5 @@
+# -*- python -*-
+
 filegroup(
     name = "external_data_sentinel",
     srcs = [':.external_data.yml'],

test/bazel_pkg_test/data/BUILD.bazel

@@ -1,3 +1,5 @@
+# -*- python -*-
+
 load("//tools:external_data.bzl",
     "external_data",
 )

test/bazel_pkg_test/tools/BUILD.bazel

@@ -0,0 +1,3 @@
+# -*- python -*-
+
+# Empty BUILD file to declare this directory as a package.

tools/BUILD.bazel

@@ -0,0 +1,3 @@
+# -*- python -*-
+
+# Empty BUILD file to declare this directory as a package.