count_backports

#!/usr/bin/python
#
# A hack to count how many commits in a given mainline release were
# backported to a previous series of stable commits.
#
# git log stable..stable | count_backports v5.17
#
import pickle, re
import gitlog

def vmatch(v1, v2):
    return v2.startswith(v1)

p_upstream = re.compile(r'commit ([0-9a-f]+) upstream', re.I)
p_upstream2 = re.compile(r'upstream commit ([0-9a-f]+)', re.I)

def upstream(patch):
    m = p_upstream.search(patch.changelog) or \
        p_upstream2.search(patch.changelog)
    if m:
        return m.group(1)
    return None

db = pickle.load(open('committags.db', 'rb'))
#
# Add 12-char versions of all commit IDs since that's what appears
# in some stable commits. Copy it to a new dict since otherwise the
# keys iterator complains.
#
VDB = { }
for commit in db.keys():
    VDB[commit[:12]] = VDB[commit] = db[commit]

versions = { }
seen = 0
input = open(0, 'rb')
patch = gitlog.grabpatch(input)
while patch:
    seen += 1
    up = upstream(patch)
    if up:
        if up in VDB:
            try:
                versions[VDB[up]] += 1
            except KeyError:
                versions[VDB[up]] = 1
    patch = gitlog.grabpatch(input)

print(f'{seen} patches seen.')
for v in sorted(versions):
    print(f'  {v}: {versions[v]} ({100*versions[v]/seen:.2f}%)')