Commit 833e4192 authored by Douglas Anderson's avatar Douglas Anderson Committed by Simon Glass

patman: Use the Change-Id, version, and prefix in the Message-Id

As per the centithread on ksummit-discuss [1], there are folks who
feel that if a Change-Id is present in a developer's local commit that
said Change-Id could be interesting to include in upstream posts.
Specifically if two commits are posted with the same Change-Id there's
a reasonable chance that they are either the same commit or a newer
version of the same commit.  Specifically this is because that's how
gerrit has trained people to work.

There is much angst about Change-Id in upstream Linux, but one thing
that seems safe and non-controversial is to include the Change-Id as
part of the string of crud that makes up a Message-Id.

Let's give that a try.

In theory (if there is enough adoption) this could help a tool more
reliably find various versions of a commit.  This actually might work
pretty well for U-Boot where (I believe) quite a number of developers
use patman, so there could be critical mass (assuming that enough of
these people also use a git hook that adds Change-Id to their
commits).  I was able to find this git hook by searching for "gerrit
change id git hook" in my favorite search engine.

In theory one could imagine something like this could be integrated
into other tools, possibly even git-send-email.  Getting it into
patman seems like a sane first step, though.

NOTE: this patch is being posted using a patman containing this patch,
so you should be able to see the Message-Id of this patch and see that
it contains my local Change-Id, which ends in 2b9 if you want to

[1] default avatarDouglas Anderson <>
parent ed7ea058
......@@ -259,12 +259,18 @@ Series-process-log: sort, uniq
unique entries. If omitted, no change log processing is done.
Separate each tag with a comma.
This tag is stripped out but is used to generate the Message-Id
of the emails that will be sent. When you keep the Change-Id the
same you are asserting that this is a slightly different version
(but logically the same patch) as other patches that have been
sent out with the same Change-Id.
Various other tags are silently removed, like these Chrome OS and
Gerrit tags:
Review URL:
Commit-xxxx: (except Commit-notes)
......@@ -21,6 +21,8 @@ class Commit:
The dict is indexed by change version (an integer)
cc_list: List of people to aliases/emails to cc on this commit
notes: List of lines in the commit (not series) notes
change_id: the Change-Id: tag that was stripped from this commit
and can be used to generate the Message-Id.
def __init__(self, hash):
self.hash = hash
......@@ -30,6 +32,7 @@ class Commit:
self.cc_list = []
self.signoff_set = set()
self.notes = []
self.change_id = None
def AddChange(self, version, info):
"""Add a new change line to the change list for a version.
......@@ -2,6 +2,7 @@
# Copyright (c) 2011 The Chromium OS Authors.
import datetime
import math
import os
import re
......@@ -14,7 +15,7 @@ import gitutil
from series import Series
# Tags that we detect and remove
re_remove = re.compile('^BUG=|^TEST=|^BRANCH=|^Change-Id:|^Review URL:'
re_remove = re.compile('^BUG=|^TEST=|^BRANCH=|^Review URL:'
# Lines which are allowed after a TEST= line
......@@ -32,6 +33,9 @@ re_cover_cc = re.compile('^Cover-letter-cc: *(.*)')
# Patch series tag
re_series_tag = re.compile('^Series-([a-z-]*): *(.*)')
# Change-Id will be used to generate the Message-Id and then be stripped
re_change_id = re.compile('^Change-Id: *(.*)')
# Commit series tag
re_commit_tag = re.compile('^Commit-([a-z-]*): *(.*)')
......@@ -156,6 +160,7 @@ class PatchStream:
# Handle state transition and skipping blank lines
series_tag_match = re_series_tag.match(line)
change_id_match = re_change_id.match(line)
commit_tag_match = re_commit_tag.match(line)
cover_match = re_cover.match(line)
cover_cc_match = re_cover_cc.match(line)
......@@ -177,7 +182,7 @@ class PatchStream:
self.state = STATE_MSG_HEADER
# If a tag is detected, or a new commit starts
if series_tag_match or commit_tag_match or \
if series_tag_match or commit_tag_match or change_id_match or \
cover_match or cover_cc_match or signoff_match or \
self.state == STATE_MSG_HEADER:
# but we are already in a section, this means 'END' is missing
......@@ -275,6 +280,16 @@ class PatchStream:
self.AddToSeries(line, name, value)
self.skip_blank = True
# Detect Change-Id tags
elif change_id_match:
value =
if self.is_log:
if self.commit.change_id:
raise ValueError("%s: Two Change-Ids: '%s' vs. '%s'" %
(self.commit.hash, self.commit.change_id, value))
self.commit.change_id = value
self.skip_blank = True
# Detect Commit-xxx tags
elif commit_tag_match:
name =
......@@ -345,6 +360,47 @@ class PatchStream:
self.warn.append('Found %d lines after TEST=' %
def WriteMessageId(self, outfd):
"""Write the Message-Id into the output.
This is based on the Change-Id in the original patch, the version,
and the prefix.
outfd: Output stream file object
if not self.commit.change_id:
# If the count is -1 we're testing, so use a fixed time
if self.commit.count == -1:
time_now = datetime.datetime(1999, 12, 31, 23, 59, 59)
time_now =
# In theory there is email.utils.make_msgid() which would be nice
# to use, but it already produces something way too long and thus
# will produce ugly commit lines if someone throws this into
# a "Link:" tag in the final commit. So (sigh) roll our own.
# Start with the time; presumably we wouldn't send the same series
# with the same Change-Id at the exact same second.
parts = [time_now.strftime("%Y%m%d%H%M%S")]
# These seem like they would be nice to include.
if 'prefix' in self.series:
if 'version' in self.series:
parts.append("v%s" % self.series['version'])
parts.append(str(self.commit.count + 1))
# The Change-Id must be last, right before the @
# Join parts together with "." and write it out.
outfd.write('Message-Id: <%s@changeid>\n' % '.'.join(parts))
def ProcessStream(self, infd, outfd):
"""Copy a stream from infd to outfd, filtering out unwanting things.
......@@ -358,6 +414,9 @@ class PatchStream:
fname = None
last_fname = None
re_fname = re.compile('diff --git a/(.*) b/.*')
while True:
line = infd.readline()
if not line:
......@@ -481,6 +540,7 @@ def FixPatches(series, fnames):
for fname in fnames:
commit = series.commits[count]
commit.patch = fname
commit.count = count
result = FixPatch(backup_dir, fname, series, commit)
if result:
print('%d warnings for %s:' % (len(result), fname))
......@@ -12,6 +12,7 @@ import checkpatch
import gitutil
import patchstream
import series
import commit
class TestPatch(unittest.TestCase):
......@@ -48,7 +49,8 @@ Signed-off-by: Simon Glass <>
arch/arm/cpu/armv7/tegra2/ap20.c | 57 ++----
arch/arm/cpu/armv7/tegra2/clock.c | 163 +++++++++++++++++
expected='''Message-Id: <19991231235959.0.I80fe1d0c0b7dd10aa58ce5bb1d9290b6664d5413@changeid>
From 656c9a8c31fa65859d924cd21da920d6ba537fad Mon Sep 17 00:00:00 2001
From: Simon Glass <>
......@@ -79,7 +81,16 @@ Signed-off-by: Simon Glass <>
patchstream.FixPatch(None, inname, series.Series(), None)
# Normally by the time we call FixPatch we've already collected
# metadata. Here, we haven't, but at least fake up something.
# Set the "count" to -1 which tells FixPatch to use a bogus/fixed
# time for generating the Message-Id.
com = commit.Commit('')
com.change_id = 'I80fe1d0c0b7dd10aa58ce5bb1d9290b6664d5413'
com.count = -1
patchstream.FixPatch(None, inname, series.Series(), com)
rc = os.system('diff -u %s %s' % (inname, expname))
self.assertEqual(rc, 0)
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