Add a script for diffing command lines based on bazel aquery outputs

Progress towards #5380 and #5883

RELNOTES: None.
PiperOrigin-RevId: 227646729

tools/cmd_line_differ/BUILD

diff --git a/tools/cmd_line_differ/BUILD b/tools/cmd_line_differ/BUILD
new file mode 100644
index 0000000..34bbffc
--- /dev/null
+++ b/tools/cmd_line_differ/BUILD
@@ -0,0 +1,41 @@
+# Copyright 2018 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+package(default_visibility = ["//visibility:public"])
+
+licenses(["notice"])  # Apache 2.0
+
+filegroup(
+    name = "srcs",
+    srcs = glob(["**"]),
+)
+
+py_binary(
+    name = "cmd_line_differ",
+    srcs = ["cmd_line_differ.py"],
+    deps = [
+        "//src/main/protobuf:analysis_py_proto",
+        "//third_party/py/abseil",
+    ],
+)
+
+py_test(
+    name = "cmd_line_differ_test",
+    srcs = ["cmd_line_differ_test.py"],
+    deps = [
+        ":cmd_line_differ",
+        "//src/main/protobuf:analysis_py_proto",
+        "//third_party/py/mock",
+    ],
+)