feat: Import diff-release.py script from the legacy common repo (#472)

* You may check the backport status of PRs by running it like:
  `python scripts/diff-release.py main 22.03`

changes/472.misc.md

@@ -0,0 +1 @@
+Add `scripts/diff-release.py` to check backport status of pull requests

scripts/diff-release.py

@@ -0,0 +1,77 @@
+import subprocess
+import sys
+import re
+
+
+rx_oneline = re.compile(r"^(?P<commit>[a-f0-9]{40}) (?P<msg>.*?)(\(#(?P<pr>\d+)\))?$")
+
+
+def do_diff_release(ref_old, ref_new):
+
+    # To ensure latest information from the repository, first fetch all branches
+    # and use the "origin" refspec prefix.
+    subprocess.run(['git', 'fetch'], capture_output=True)
+    if not ref_old.startswith('origin/'):
+        ref_old = 'origin/' + ref_old
+    if not ref_new.startswith('origin/'):
+        ref_new = 'origin/' + ref_new
+
+    proc = subprocess.run([
+        'git', 'merge-base', ref_old, ref_new,
+    ], capture_output=True)
+    common_ancestor = proc.stdout.strip().decode()
+
+    proc = subprocess.run([
+        'git', 'rev-list', '--pretty=oneline', f'{common_ancestor}..{ref_old}',
+    ], capture_output=True)
+    old_rev_list = proc.stdout.decode().splitlines()
+
+    proc = subprocess.run([
+        'git', 'rev-list', '--pretty=oneline', f'{common_ancestor}..{ref_new}',
+    ], capture_output=True)
+    new_rev_list = proc.stdout.decode().splitlines()
+
+    pr_desc_map = {}
+
+    old_pr_set = set()
+    for rev in old_rev_list:
+        if (
+            (m := rx_oneline.search(rev.strip())) is not None and
+            (pr := m.group('pr')) is not None
+        ):
+            old_pr_set.add(int(pr))
+            pr_desc_map[int(pr)] = m.group('msg')
+
+    new_pr_set = set()
+    for rev in new_rev_list:
+        if (
+            (m := rx_oneline.search(rev.strip())) is not None and
+            (pr := m.group('pr')) is not None
+        ):
+            new_pr_set.add(int(pr))
+            pr_desc_map[int(pr)] = m.group('msg')
+
+    print()
+    print(f"The common ancestor commit:\n{common_ancestor}")
+
+    print()
+    print(f"All PRs in the {ref_new} branch since {common_ancestor[:12]}:")
+    print("  " + ", ".join(map(str, sorted(new_pr_set))))
+
+    print()
+    print(f"All PRs in the {ref_old} branch since {common_ancestor[:12]}:")
+    print("  " + ", ".join(map(str, sorted(old_pr_set))))
+
+    print()
+    print(f"PRs only in the {ref_new} branch:")
+    for pr in sorted(new_pr_set - old_pr_set, reverse=True):
+        print(f"  {pr} {pr_desc_map[pr]}")
+
+    print()
+    print(f"PRs only in the {ref_old} branch:")
+    for pr in sorted(old_pr_set - new_pr_set, reverse=True):
+        print(f"  {pr} {pr_desc_map[pr]}")
+
+
+if __name__ == "__main__":
+    do_diff_release(sys.argv[1], sys.argv[2])