Script to check current diff name

Summary: D10049

Test Plan:
Common:
- create new diff in any arc-enabled repo
- run script against this repo: `../yugabyte-db/arcanist_util/check-diff-name.py -b -r ../internal-services`

For `-b` flag:
- create diff on branch
- push this branch to git
- run script without `-b` - it will not show any diff
- run script with `-b` - it start seeing revision

Reviewers: bogdan, mbautin, steve.varnau

Reviewed By: steve.varnau

Subscribers: steve.varnau, #devops

Differential Revision: https://phabricator.dev.yugabyte.com/D10809

arcanist_util/check-diff-name.py

@@ -0,0 +1,76 @@
+#!/usr/bin/env python3
+
+import os
+import re
+import argparse
+
+from subprocess import check_output
+
+
+DIFF_NAME_RE = re.compile(
+    r'(?P<backport>\[BACKPORT [0-9\.\-]+\])?\[(?P<issues>(#[0-9]+, )*#[0-9]+)\] '
+    r'(?P<area>[\w,\s]+): (?P<description>.{10,100})$')
+
+# Tests - correct and incorrect samples
+CORRECT_NAMES = {
+    "multiple issue numbers": "[#1234, #1235] area: Ideally short title",
+    "one issue and one backport": "[BACKPORT 2.2-1][#1235] area: Ideally short title",
+    "one issue, no backports": "[#1235] area: Ideally short title",
+    "different issue numbers": "[BACKPORT 2.2-1][#1235, #1, #10292012] area: Ideally short title",
+    "complex area":
+        "[BACKPORT 2.2-1][#1235] area of, probably, some 1 Interest: Ideally short title"
+}
+
+for reason, cname in CORRECT_NAMES.items():
+    assert DIFF_NAME_RE.match(cname), \
+        f"New DIFF_NAME_RE doesn't match on '{cname}' which has '{reason}'"
+
+INCORRECT_NAMES = {
+    "more than one backport in one diff":
+        "[BACKPORT 2.1][BACKPORT 2.2-1][#1235, #1, #10292012] area: Ideally short title",
+    "illegal literal in build number for backport":
+        "[BACKPORT 2.2-b1][#1235, #1, #10292012] area: Ideally short title",
+    "wrong issues list (trailing comma)":
+        "[BACKPORT 2.2-1][#1235, #1, #10292012,] area: Ideally short title",
+    "wrong issue number (comma)":
+        "[BACKPORT 2.2-1][#1,235, #1, #10292012] area: Ideally short title",
+    "wrong issues list (leading comma)":
+        "[BACKPORT 2.2-1][,#1235, #1, #10292012] area: Ideally short title",
+    "wrong issue number (dash)":
+        "[BACKPORT 2.2-1][#12-5, #b1, #1029?2012] area: Ideally short title",
+    "too short title":
+        "[BACKPORT 2.2-1][#1235, #1, #10292012] area: Ideally s",
+    "too long title":
+        "[BACKPORT 2.2-1][#1235, #1, #10292012] area: Ideally short title Ideally short title "
+        "Ideally short title Ideally short title Ideally short title ..."
+}
+
+for reason, iname in INCORRECT_NAMES.items():
+    assert not DIFF_NAME_RE.match(iname), \
+        f"New DIFF_NAME_RE doesn't warn on '{iname}' which has '{reason}'"
+
+parser = argparse.ArgumentParser(
+    description="Tool to check Phabricator diff name of current working copy (CWD)")
+parser.add_argument('--base', '-b', action='store_true',
+                    help='Use master branch as merge base to detect diff (for arc which call)')
+parser.add_argument('--repository', '-r', default=os.path.dirname(__file__),
+                    help='What repository to inspect')
+
+args = parser.parse_args()
+
+arc_which_cmd = ['arc', 'which']
+if args.base:
+    arc_which_cmd += ['--base', 'git:merge-base(origin/master)']
+arc_which_out = check_output(arc_which_cmd, cwd=args.repository).decode('utf-8')
+diff_descs = re.findall('D[0-9]+.*', arc_which_out)
+if diff_descs:
+    for diff_desc in diff_descs:
+        diff_id, diff_name = re.search('(D[0-9]+) (.*)', diff_desc).groups()
+        parsed_diff_name = DIFF_NAME_RE.match(diff_name)
+        if parsed_diff_name:
+            print(f"ok: Diff {diff_id} has correct name")
+        else:
+            print(f"error: Diff {diff_id} name "
+                  f"should fit '{DIFF_NAME_RE.pattern}' but it is '{diff_name}'")
+else:
+    print("advice: No diffs were found, time to create one ?")