ci-license-scan: Add proposed whitelist

While working with license scan is very common to add whitelist for
files and folders. To make this job easier, allow ci-license-scan to
propose a whitelist based on known patterns.

This feature is only meant to help developers to reduce the overheard
of the manual work, hence, the proposed changed need to be carefully
reviewed.

Signed-off-by: Walter Lozano <walter.lozano@collabora.com>

tools/ci-license-scan

@@ -388,6 +388,36 @@ def get_pattern_broadness(pattern):
     return pattern.count("*") + pattern.count("?")
 
 
+def propose_whitelist(license):
+    reason = None
+    if license.file.startswith("debian/"):
+        reason = "# debian metadata is not part of build artifacts\n"
+    elif license.file.startswith(("doc/", "docs/")):
+        reason = "# docs are not meant to be installed in target\n"
+    elif license.file.startswith(("test/", "tests/", "testsuite/")):
+        reason = "# tests are not meant to be installed in target\n"
+    elif license.file.startswith(("example/", "examples/")):
+        reason = "# examples are not meant to be installed in target\n"
+    elif license.file.startswith("m4/") or license.file.endswith(".m4"):
+        reason = "# preprocesor files are not meant to be installed in target\n"
+    elif license.file.startswith(("build/", "build-aux")) or license.file.endswith(
+        (".am", ".in", ".make")
+    ):
+        reason = "# build scripts are not meant to be installed in target\n"
+    else:
+        reason = "# PLEASE FILL THE REASON TO WHITELIST\n"
+    if reason:
+        with open("debian/apertis/copyright.whitelist", "a+") as f:
+            f.seek(0)
+            buf = f.read()
+            data = ""
+            if len(buf) and buf[-1] != "\n":
+                data += "\n"
+            data += reason
+            data += license.file + "\n"
+            f.write(data)
+
+
 def main():
     parser = argparse.ArgumentParser()
     parser.add_argument(
@@ -434,6 +464,11 @@ def main():
         default=["debian/apertis/copyright.whitelist"],
         help="extra file whitelist",
     )
+    parser.add_argument(
+        "--propose-whitelist",
+        action="store_true",
+        help="propose a whitelist in case of failure",
+    )
     args = parser.parse_args()
     print("%s fail on change" % ("Will" if args.fail_on_change else "Will not"))
     print(
@@ -599,9 +634,18 @@ def main():
         for license in sorted(unknown_licensed):
             print(f" UNKNOWN license entry found: {license}", file=sys.stderr)
             should_fail = args.fail_on_unknown
+            if args.propose_whitelist:
+                propose_whitelist(license)
         for license in sorted(bad_licenses):
             print(f" Blacklisted license entry found: {license}", file=sys.stderr)
+            if args.propose_whitelist:
+                propose_whitelist(license)
             should_fail = True
+        if args.propose_whitelist:
+            print(
+                "\nPROPOSED WHITELIST HAVE BEEN ADDED, PLEASE REVIEW THEM!!!\n",
+                file=sys.stderr,
+            )
         if should_fail:
             sys.exit(1)