Fix: Changelog script was broken on markdown changelogs (#13195)

.github/changelog.py

@@ -0,0 +1,36 @@
+import sys
+
+"""
+This script assumes changelogs use the following format:
+    ## <major>.x (eg. "## 15.x") to indicate a major version series
+    ### <major>.<minor>[-<suffix>] <date etc> (eg. "## 15.0 (2025-04-01)", "### 15.1-beta1 (2024-12-25)") to indicate an individual version
+"""
+
+def main():
+    current_version = sys.argv[1]
+    stable_version = current_version.split("-")[0]
+    major_version = current_version.split(".")[0]
+    # set when current version is found
+    current_found = False
+
+    with open("changelog.md", "r") as file:
+        for line in file:
+            if line.startswith("### "):
+                if not line.startswith(f"### {current_version} ") and not current_found:
+                    # First version in changelog should be the current one
+                    sys.stderr.write(f"Changelog doesn't start with current version ({current_version})\n")
+                    sys.exit(1)
+                if not line.startswith(f"### {stable_version}"):
+                    # Reached a previous stable version
+                    break
+                if line.startswith(f"### {current_version} "):
+                    current_found = True
+            elif line.startswith("## "):
+                if not line.startswith(f"## {major_version}.x"):
+                    # Reached a previous major version
+                    break
+
+            print(line.rstrip())
+
+if __name__ == '__main__':
+    main()