User:Jack Phoenix/gerrit

Quick and dirty gerrit tutorial. Hardly an ideal workflow, but it works.

Prerequisites (Windows 7 with PuTTY is assumed scratch that, I use portable-git under Windows 7 but this should work with most Windows boxes and naturally with all *NIX-like boxes):

• SSH key added to wikitech and gerrit — remember to add it to both places!
• git client of some kind (I use portable-git — a portable version of the command-line binary stuff)

1. Start up ssh-agent (UNIX equivalent of PuTTY's Pageant) with: eval `ssh-agent`
2. Load your private key into ssh-agent: ssh-add /path/to/your/private/key/in/openssh/format, i.e. ssh-add /c/Users/Admin/Desktop/privatekey-openssh if your (Windows) user name is "Admin" and your private key (the OpenSSH one, which has to be explicitly generated in PuTTYGen from the "Conversions" menu) file is named "privatkey-openssh" and you stored it in your desktop
3. Let's clone what we want (this example uses the SocialProfile extension): ssh://YOUR WIKITECH USERNAME@gerrit.wikimedia.org:29418/mediawiki/extensions/SocialProfile.git
4. In the newly created SocialProfile directory, go to .git/config and add these lines there & save changes:

[remote "gerrit"]
	url = ssh://YOUR WIKITECH USERNAME@gerrit.wikimedia.org:29418/mediawiki/extensions/SocialProfile.git
	fetch = +refs/heads/*:refs/remotes/gerrit/*

5. Save the following as SocialProfile/.git/hooks/commit-msg:

#!/bin/sh
# From Gerrit Code Review 2.7-rc2-507-g1e7090b
#
# Part of Gerrit Code Review (http://code.google.com/p/gerrit/)
#
# Copyright (C) 2009 The Android Open Source Project
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

unset GREP_OPTIONS

CHANGE_ID_AFTER="Bug|Issue"
MSG="$1"

# Check for, and add if missing, a unique Change-Id
#
add_ChangeId() {
	clean_message=`sed -e '
		/^diff --git a\/.*/{
			s///
			q
		}
		/^Signed-off-by:/d
		/^#/d
	' "$MSG" | git stripspace`
	if test -z "$clean_message"
	then
		return
	fi

	# Does Change-Id: already exist? if so, exit (no change).
	if grep -i '^Change-Id:' "$MSG" >/dev/null
	then
		return
	fi

	id=`_gen_ChangeId`
	T="$MSG.tmp.$$"
	AWK=awk
	if [ -x /usr/xpg4/bin/awk ]; then
		# Solaris AWK is just too broken
		AWK=/usr/xpg4/bin/awk
	fi

	# How this works:
	# - parse the commit message as (textLine+ blankLine*)*
	# - assume textLine+ to be a footer until proven otherwise
	# - exception: the first block is not footer (as it is the title)
	# - read textLine+ into a variable
	# - then count blankLines
	# - once the next textLine appears, print textLine+ blankLine* as these
	#   aren't footer
	# - in END, the last textLine+ block is available for footer parsing
	$AWK '
	BEGIN {
		# while we start with the assumption that textLine+
		# is a footer, the first block is not.
		isFooter = 0
		footerComment = 0
		blankLines = 0
	}

	# Skip lines starting with "#" without any spaces before it.
	/^#/ { next }

	# Skip the line starting with the diff command and everything after it,
	# up to the end of the file, assuming it is only patch data.
	# If more than one line before the diff was empty, strip all but one.
	/^diff --git a/ {
		blankLines = 0
		while (getline) { }
		next
	}

	# Count blank lines outside footer comments
	/^$/ && (footerComment == 0) {
		blankLines++
		next
	}

	# Catch footer comment
	/^\[[a-zA-Z0-9-]+:/ && (isFooter == 1) {
		footerComment = 1
	}

	/]$/ && (footerComment == 1) {
		footerComment = 2
	}

	# We have a non-blank line after blank lines. Handle this.
	(blankLines > 0) {
		print lines
		for (i = 0; i < blankLines; i++) {
			print ""
		}

		lines = ""
		blankLines = 0
		isFooter = 1
		footerComment = 0
	}

	# Detect that the current block is not the footer
	(footerComment == 0) && (!/^\[?[a-zA-Z0-9-]+:/ || /^[a-zA-Z0-9-]+:\/\//) {
		isFooter = 0
	}

	{
		# We need this information about the current last comment line
		if (footerComment == 2) {
			footerComment = 0
		}
		if (lines != "") {
			lines = lines "\n";
		}
		lines = lines $0
	}

	# Footer handling:
	# If the last block is considered a footer, splice in the Change-Id at the
	# right place.
	# Look for the right place to inject Change-Id by considering
	# CHANGE_ID_AFTER. Keys listed in it (case insensitive) come first,
	# then Change-Id, then everything else (eg. Signed-off-by:).
	#
	# Otherwise just print the last block, a new line and the Change-Id as a
	# block of its own.
	END {
		unprinted = 1
		if (isFooter == 0) {
			print lines "\n"
			lines = ""
		}
		changeIdAfter = "^(" tolower("'"$CHANGE_ID_AFTER"'") "):"
		numlines = split(lines, footer, "\n")
		for (line = 1; line <= numlines; line++) {
			if (unprinted && match(tolower(footer[line]), changeIdAfter) != 1) {
				unprinted = 0
				print "Change-Id: I'"$id"'"
			}
			print footer[line]
		}
		if (unprinted) {
			print "Change-Id: I'"$id"'"
		}
	}' "$MSG" > "$T" && mv "$T" "$MSG" || rm -f "$T"
}
_gen_ChangeIdInput() {
	echo "tree `git write-tree`"
	if parent=`git rev-parse "HEAD^0" 2>/dev/null`
	then
		echo "parent $parent"
	fi
	echo "author `git var GIT_AUTHOR_IDENT`"
	echo "committer `git var GIT_COMMITTER_IDENT`"
	echo
	printf '%s' "$clean_message"
}
_gen_ChangeId() {
	_gen_ChangeIdInput |
	git hash-object -t commit --stdin
}


add_ChangeId

6. Now you're ready to make changes. Make them, and then run cd <extension> (this will put you into the directory of that extension). Remember to git add any new files etc. and then git commit, write a commit message (for "my" stuff you can safely ignore the official commit message guidelines, I find them too restricting and outright stupid; if git clients "can't" handle a commit message longer than 60 characters, it's not our problem, I blame Linus)...
7. Send your changes to gerrit: git push gerrit HEAD:refs/for/master
8. That's it!
9. Watch as jerkins -1's your new patchset over trivial, irrelevant stuff that absolutely nobody cares about, such as missing API i18n messages or whatever. (You can work around this by removing jerkins as a reviewer and manually giving the patchset V+2 CR+2, provided you have sufficient rights to do that.)