ci: detect what changed in a PR and if full sanitycheck is needed.

Script to detect if full sanitycheck should run or if we can skip it and
just run the code that actuallt changed (in samples/tests).

Signed-off-by: Anas Nashif <anas.nashif@intel.com>

scripts/ci/sanitycheck_ignore.txt

@@ -0,0 +1,26 @@
+# Add one pattern per line.
+#
+# The patterns listed in this file will be compared with the list of files
+# changed in a patch series (Pull Request) and if all files in the pull request
+# are matched, then sanitycheck will not do a full run and optionally will only
+# run on changed tests or boards.
+#
+.clang-format
+.codecov.yml
+.editorconfig
+.gitattributes
+.gitignore
+.known-issues
+.mailmap
+.uncrustify.cfg
+CODEOWNERS
+LICENSE
+Makefile
+tests/*
+samples/*
+*.rst
+*.md
+# if we change this file or associated script, it should not trigger a full
+# sanitycheck.
+scripts/ci/sanitycheck_ignore.txt
+scripts/ci/what_changed.py

scripts/ci/what_changed.py

@@ -0,0 +1,54 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: Apache-2.0
+# Copyright (c) 2020 Intel Corporation
+# Check if full sanitycheck is needed.
+
+import os
+import sh
+import argparse
+import fnmatch
+
+
+if "ZEPHYR_BASE" not in os.environ:
+    exit("$ZEPHYR_BASE environment variable undefined.")
+
+repository_path = os.environ['ZEPHYR_BASE']
+sh_special_args = {
+    '_tty_out': False,
+    '_cwd': repository_path
+}
+
+def parse_args():
+    parser = argparse.ArgumentParser(
+                description="Check if change requires full sanitycheck")
+    parser.add_argument('-c', '--commits', default=None,
+            help="Commit range in the form: a..b")
+    return parser.parse_args()
+
+def main():
+    args = parse_args()
+    if not args.commits:
+        exit(1)
+
+    # pylint does not like the 'sh' library
+    # pylint: disable=too-many-function-args,unexpected-keyword-arg
+    commit = sh.git("diff", "--name-only", args.commits, **sh_special_args)
+    files = commit.split("\n")
+
+    with open("scripts/ci/sanitycheck_ignore.txt", "r") as sc_ignore:
+        ignores = sc_ignore.read().splitlines()
+        ignores = filter(lambda x: not x.startswith("#"), ignores)
+
+    found = []
+    files = list(filter(lambda x: x, files))
+
+    for pattern in ignores:
+        if pattern:
+            found.extend(fnmatch.filter(files, pattern))
+
+    if sorted(files) != sorted(found):
+        print("full")
+
+
+if __name__ == "__main__":
+    main()