reintroduce create_skipfile.py script for gerrit

The script was removed in c1626bb
but for the usecase where the user does not want to analyze
all the source files in the review it is needed.

Makefile

@@ -54,6 +54,9 @@ package_tu_collector: build_tu_collector package_dir_structure
 	cd $(CC_BUILD_DIR) && \
 	ln -sf ../lib/python3/tu_collector/tu_collector.py bin/tu_collector
 
+package_gerrit_skiplist:
+	cp -rp $(CC_TOOLS)/skiplist/create_skipfile.py $(CC_BUILD_DIR)/bin
+
 build_report_converter:
 	$(MAKE) -C $(ROOT)/tools/report-converter build
 
@@ -90,7 +93,7 @@ package_statistics_collector: build_statistics_collector package_dir_structure
 	cd $(CC_BUILD_DIR) && \
 	ln -sf ../lib/python3/codechecker_statistics_collector/cli.py bin/post-process-stats
 
-package: package_dir_structure set_git_commit_template package_plist_to_html package_tu_collector package_report_converter package_report_hash package_merge_clang_extdef_mappings package_statistics_collector
+package: package_dir_structure set_git_commit_template package_plist_to_html package_tu_collector package_report_converter package_report_hash package_merge_clang_extdef_mappings package_statistics_collector package_gerrit_skiplist
 	BUILD_DIR=$(BUILD_DIR) BUILD_LOGGER_64_BIT_ONLY=$(BUILD_LOGGER_64_BIT_ONLY) $(MAKE) -C $(CC_ANALYZER) package_analyzer
 	BUILD_DIR=$(BUILD_DIR) $(MAKE) -C $(CC_WEB) package_web
 

docs/jenkins_gerrit_integration.md

@@ -200,9 +200,16 @@ CodeChecker log -b "build command" -o compile_cmd.json
 # Run the tests. If this fails, the result will be verified -1.
 make tests
 
+export CC_CHANGED_FILES="$WORKSPACE/files-changed"
+export CC_SKIPFILE="$WORKSPACE/skipfile"
+
+# create_skipfile.py script can be found in the bin directory in the CodeChecker package.
+python create_skipfile.py $CC_CHANGED_FILES $CC_SKIPFILE
+
 # Check the project.
 CodeChecker analyze \
   -e sensitive \
+  --ignore $CC_SKIPFILE \
   -j 16 \
   compile_cmd.json \
   -o cc_reports
@@ -213,7 +220,6 @@ CodeChecker analyze \
 # gerrit_review.json file in this directory that is later going to be loaded
 # as an Environment Variable.
 CC_REPORT_URL="http://your_jenkins_address/userContent/$JOB_NAME/$BUILD_NUMBER/index.html" \
-CC_CHANGED_FILES="$WORKSPACE/files-changed" \
 CC_REPO_DIR="$WORKSPACE/repo_dir" \
 CodeChecker cmd diff \
   -b clangsa_checkers-merge \
@@ -222,6 +228,11 @@ CodeChecker cmd diff \
   --new \
   -o html gerrit \
   -e $JENKINS_HOME/userContent/$JOB_NAME/$BUILD_NUMBER
+
+# Craft the review message and write it into a file,
+# that is later going to be loaded as an Environment Variable.
+echo DATA_TO_POST=\\ > review
+CodeChecker parse --ignore $CC_SKIPFILE cc_reports -e gerrit >> review
 ```
 
 ### Inject environment variable <a name="inject-environment-variable"></a>

tools/skiplist/create_skipfile.py

@@ -0,0 +1,54 @@
+# -------------------------------------------------------------------------
+#
+#  Part of the CodeChecker project, under the Apache License v2.0 with
+#  LLVM Exceptions. See LICENSE for license information.
+#  SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+#
+# -------------------------------------------------------------------------
+"""
+Converts Gerrit Review changed files list to CodeChecker skipfile.
+"""
+
+import argparse
+import json
+import re
+
+
+def create_skipfile(files_changed, skipfile):
+    # File is likely to contain some garbage values at start,
+    # only the corresponding json should be parsed.
+    json_pattern = re.compile(r"^\{.*\}")
+    for line in files_changed.readlines():
+        if re.match(json_pattern, line):
+            for filename in json.loads(line):
+                if "/COMMIT_MSG" in filename:
+                    continue
+                skipfile.write("+*/%s\n" % filename)
+
+    skipfile.write("-*\n")
+
+
+def main():
+    parser = argparse.ArgumentParser(
+        description="Converts Gerrit Review changed files "
+        "json to CodeChecker skipfile."
+    )
+    parser.add_argument(
+        "files_changed",
+        type=argparse.FileType("r"),
+        help="Path of changed files json from Gerrit.",
+    )
+    parser.add_argument(
+        "skipfile",
+        nargs="?",
+        default="skipfile",
+        type=argparse.FileType("w"),
+        help="Path of the skipfile output. Default is ./skipfile.",
+    )
+    args = parser.parse_args()
+
+    create_skipfile(args.files_changed, args.skipfile)
+
+
+if __name__ == "__main__":
+    main()