MAINT: Added script to automatically generate Changelog

The script automatically parses the new merge commits between two given
tags and tries its best to generate a Changelog out of it.

2 files changed, 197 insertions, 0 deletions

diff --git a/scripts/commitMessage/CommitMessage.py b/scripts/commitMessage/CommitMessage.py
new file mode 100644
index 000000000..a9a778ed9
--- /dev/null
+++ b/scripts/commitMessage/CommitMessage.py
@@ -0,0 +1,56 @@
+import re
+
+class CommitFormatError(Exception):
+
+    def __init__(self, msg):
+        Exception(msg)
+
+class CommitMessage:
+    knownTypes = ["BREAK", "FEAT", "FIX", "FORMAT", "DOCS", "TEST", "MAINT", "CI", "REFAC", "BUILD", "TRANSLATION"]
+
+    def __init__(self, commitString):
+        lines = commitString.strip().split("\n")
+
+        if len(lines) < 1 or lines[0].strip() == "":
+            raise CommitFormatError("Invalid commit content")
+
+        subjectPattern = re.compile("^([A-Z\-_/]+)(?:\(([0-9a-zA-Z\-_, ]+)\))?:\s*(.+)$")
+
+        match = re.match(subjectPattern, lines[0])
+
+        if not match:
+            raise CommitFormatError("The provided commit's subject line does not follow the required pattern")
+
+        types = match.group(1).split("/") if not match.group(1) is None else []
+        scopes = match.group(2).split(",") if not match.group(2) is None else []
+        summary = match.group(3).strip() if not match.group(3) is None else ""
+
+        if len(types) == 0:
+            raise CommitFormatError("Missing type")
+
+        if len(summary) == 0:
+            raise CommitFormatError("Missing summary")
+
+        self.m_summary = summary
+
+        types = [x.strip() for x in types]
+        scopes = [x.strip().lower() for x in scopes]
+
+        for currentType in types:
+            if currentType == "":
+                raise CommitFormatError("Subsequent \"/\" not allowed for separating types")
+
+            if not currentType in self.knownTypes:
+                raise CommitFormatError("Unknown type \"%s\" (or incorrect spelling)" % currentType)
+
+        self.m_types = types
+
+        for currentScope in scopes:
+            if currentScope == "":
+                raise CommitFormatError("Empty scope not allowed")
+        
+        self.m_scopes = scopes
+
+        self.m_body = "\n".join(lines[1 : ]) if len(lines) > 1 else ""
+
+
diff --git a/scripts/generateChangelog.py b/scripts/generateChangelog.py
new file mode 100755
index 000000000..f6cf1c03c
--- /dev/null
+++ b/scripts/generateChangelog.py
@@ -0,0 +1,141 @@
+#!/usr/bin/env python3
+#
+# Copyright 2021 The Mumble Developers. All rights reserved.
+# Use of this source code is governed by a BSD-style license
+# that can be found in the LICENSE file at the root of the
+# Mumble source tree or at <https://www.mumble.info/LICENSE>.
+
+import argparse
+import platform
+import subprocess
+
+from commitMessage.CommitMessage import CommitMessage, CommitFormatError
+
+def cmd(args):
+    shell = platform.system() == 'Windows'
+    p = subprocess.Popen(args, shell=shell, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+    stdout, stderr = p.communicate()
+    if p.returncode != 0:
+        raise Exception('cmd(): {0} failed with status {1}: {2}'.format(args, p.returncode, stderr))
+    return stdout.decode('utf-8')
+
+def isRelevantCommit(commitLine):
+    if commitLine.strip() == "":
+        return False
+    
+    components = commitLine.split()
+
+    if len(components) < 2:
+        return False
+
+    # First component is commit hash
+    # We only consider merge commits to be relevant
+    return components[1].lower() == "merge"
+
+def formatChangeLine(line, prNumber, target):
+    if target == "github":
+        return "- {} (#{})".format(line, prNumber)
+    elif target == "website":
+        return "- {} ({{{{< issue {} >}}}})".format(line, prNumber)
+    else:
+        return "- {} (https://github.com/mumble-voip/mumble/pull/{})".format(line, prNumber)
+
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument("FROM_TAG", help="Tag or commit to start the diff from")
+    parser.add_argument("TO_TAG", help="Tag or commit to end the diff at")
+    parser.add_argument("--target", choices=["github", "website", "other"], help="Generate the Changelog in a format suitable for this target",
+            default="other")
+    args = parser.parse_args()
+
+    commits = cmd(["git", "log" ,"--format=oneline",  "--date=short", "{}..{}".format(args.FROM_TAG, args.TO_TAG)]).split("\n")
+    commits = list(filter(isRelevantCommit, commits))
+
+    serverChanges = []
+    clientChanges = []
+    sharedChanges = []
+    miscChanges   = []
+
+    skipTypes = set(["FORMAT", "DOCS", "TEST", "MAINT", "CI", "REFAC", "BUILD", "TRANSLATION"])
+
+    for commitLine in commits:
+        parts = commitLine.split(maxsplit=1)
+        commitHash = parts[0]
+        commitTitle = parts[1]
+
+        assert ":" in commitTitle
+        assert "#" in commitTitle
+
+        prTagStart = commitTitle.find("#")
+        prTagEnd = commitTitle.find(":")
+        assert prTagStart + 1 < prTagEnd
+
+        # Extract PR number
+        prNumber = commitTitle[prTagStart + 1 : prTagEnd]
+        # Cut out PR information from commit title
+        commitTitle = commitTitle[prTagEnd + 1 : ].strip()
+
+        try:
+            commit = CommitMessage(commitTitle)
+
+            if len(set(commit.m_types) & skipTypes) > 0:
+                # We don't list these changes in the changelog
+                continue
+
+            targetGroups = []
+            if "client" in commit.m_scopes:
+                targetGroups.append(clientChanges)
+            if "server" in commit.m_scopes:
+                targetGroups.append(serverChanges)
+            if "shared" in commit.m_scopes:
+                targetGroups.append(sharedChanges)
+            if len(targetGroups) == 0:
+                targetGroups.append(miscChanges)
+
+            prefix = ""
+            if "FEAT" in commit.m_types:
+                prefix = "Added: "
+            elif "FIX" in commit.m_types:
+                prefix = "Fixed: "
+            else:
+                prefix = "Unknown: "
+
+            for currentTarget in targetGroups:
+                currentTarget.append(formatChangeLine(prefix + commit.m_summary, prNumber, args.target))
+        except CommitFormatError:
+            # We can't classify the change -> assume misc
+            miscChanges.append(formatChangeLine("Unknown: " + commitTitle, prNumber, args.target))
+
+
+    if len(clientChanges) > 0:
+        print("### Client")
+        print()
+        print("\n".join(sorted(clientChanges)))
+        print()
+        print()
+
+    if len(serverChanges) > 0:
+        print("### Server")
+        print()
+        print("\n".join(sorted(serverChanges)))
+        print()
+        print()
+
+    if len(sharedChanges) > 0:
+        print("### Both")
+        print()
+        print("\n".join(sorted(sharedChanges)))
+        print()
+        print()
+
+    if len(miscChanges):
+        print("### Miscellaneous")
+        print()
+        print("\n".join(sorted(miscChanges)))
+        print()
+
+
+
+if __name__ == "__main__":
+    main()