scripts/issue.py: Parse multiple statuses in the same field

For issues with complex fixes, sometimes only part of the fix is
applied to a stable branch.  We record this by marking the issue as
some combination of "released", "pending", and "needed".

Change issue.parse_status() to be able to read past the first status
and coalesce the statuses as necessary.

1 files changed, 50 insertions, 9 deletions

diff --git a/scripts/issue.py b/scripts/issue.py
index 31484f13..ee8a1c59 100644
--- a/scripts/issue.py
+++ b/scripts/issue.py
@@ -1,6 +1,7 @@
 from debian import deb822
 import os.path
 import re
+import sys
 
 
 class issue(deb822.Deb822):
@@ -65,13 +66,53 @@ def get_issues(dir):
     return [ issue(os.path.join(dir, f)) for f in L ]
 
 
+_status_re = re.compile(
+    r'\s*(\S*)'
+    r'(?:\s*\([^\s)]+\))?'  # optional version
+    r'(?:\s*\[[^]]+\])?'    # optional changerefs
+    r'(?:\s*"[^"]+")?'      # optional comment
+    )
+
+
+_comma_re = re.compile(r'\s*,\s*')
+
+
+def _coalesce_state(old_state, new_state):
+    if old_state is None:
+        return new_state
+    # "needed" overrides everything else
+    if 'needed' in [old_state, new_state]:
+        return 'needed'
+    # "pendng" overrides everything but "needed"
+    if 'pending' in [old_state, new_state]:
+        return 'pending'
+    # We don't expect to use more than one of "released", "ignored",
+    # or "N/A" and it's not clear which should override which
+    if old_state != new_state:
+        print(f'W: Not sure how to coalesce status {old_state} and {new_state}',
+              file=sys.stderr)
+    return old_state
+
+
 def parse_status(s):
-    ws = '\s*'
-    state = '(?P<state>\S*)'
-
-    statusre = re.compile(ws + state)
-    m = statusre.match(s)
-    if not m:
-        raise SyntaxError
-    else:
-        return m.groupdict()
+    state = None
+    start = 0
+
+    while True:
+        m = _status_re.match(s[start:])
+        if not m:
+            raise SyntaxError(f'bad status {s[start:]}')
+        start += m.end()
+
+        # Coalesce with last status
+        state = _coalesce_state(state, m.group(1))
+
+        # End of field?
+        if start == len(s) or s[start:].isspace():
+            return {'state': state}
+
+        # No, must be followed by a comma separator
+        m = _comma_re.match(s[start:])
+        if not m:
+            raise SyntaxError(f'missing separator in{s[start:]}')
+        start += m.end()