git commit 中的change-id

git commit 中的change-id

为什么要使用change-id

保证已经提交审核的修订通过审核入库后，被别的分支 cherry-pick 后再推送至服务器时不会产生新的重复的评审任务。Gerrit 设计了一套方法，即要求每个提交包含唯一的 Change-Id，这个 Change-Id 因为出现在日志中，当执行 cherry-pick 时也会保持，Gerrit 一旦发现新的提交包含了已经处理过的 Change-Id ，就不再为该修订创建新的评审任务和 task-id，而直接将提交入库。

解决“ERROR：missing Change-Id in commit message”

在执行git push origin Head:refs/for/xxxx时有时会报出这样的错误，也就是在commit Message仅仅包含如“feature：xxxx”等title这样的信息而缺少Change-Id。

手动解决

执行git commit --amend，在title下面空出一行后，将错误提示中的change-id复制到Message中。再push。注意，一定要空出一行，否则Git会把其作为title的一部分处理

利用commit-msg hook自动生成change-id

将如下的的hook脚本复制到Git项目中.git/hooks下，并命名为“commit-msg”。一般情况 .git/hooks 下会包含一个叫“commit-msg.sample”的文件，可以把它删除。添加完成后，执行chmod u+x .git/hooks/commit-msg保证hook可执行。

commit-msg hook脚本

#!/bin/sh
# From Gerrit Code Review 2.6
#
# 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