Git bisect with merged commit

Question

我的历史看起来像这样:

* 3830e61 Add data escaping.              (Bad)
* 0f5e148 Improve function for getting page template.
*   aaf8dc5 Merge branch 'navigation'
|\
| * 3e667f8 Add icons.
| * 43a07b1 Add menu styles.              (Breaks)
| * 107ca95 Add Responsive Nav.           (Good)
* | ea3d736 Add ‘Admin’ notice.
* | 17ca0bb Update placeholder text.
|/
* f52cc34 Add featured image.
* 2abd954 Style placeholders.

我正在努力学习更多git bisect,但我对这段历史遇到了麻烦.我知道这107ca95很好而且3830e61很糟糕.当我运行时git bisect,提交107ca95..3e667f8被忽略.我碰巧知道这43a07b1是引入回归的提交,但它永远不会被评估.

这大致是我所做的:

git checkout master
git bisect start
git bisect bad
git bisect good 107ca95
git bisect bad (multiple times)

无论我做什么,107ca95..3e667f8都不会被检查出来进行测试.

有没有什么方法可以在bisect中基本上"扁平化"历史来测试这些提交？我知道我可以使用互动rebase来平整历史,但我不想这样做.

Answer 1

这是一个非常古老但没有答案的问题.我决定进行调查,发现我可以证明Git的行为与问题所说的不同.一种解释是Git改进了bisect的算法,或者提问者在标记提交时犯了一个错误.

我正在努力学习更多和git bisect,但我对这段历史遇到了麻烦.我知道这107ca95很好而且3830e61很糟糕.当我运行git bisect时,将107ca95..3e667f8忽略提交.我碰巧知道这43a07b1是引入回归的提交,但它永远不会被评估.

我写了一些代码来检查它是否被评估.我的测试显示它已被评估.运行下面的代码并验证是否Add menu styles.显示带有消息的提交.

进一步评论:

• "提交107ca95..3e667f8被忽略":请注意,您标记为"好"的提交将不会被评估,因为git已经知道它是好的.
• 请阅读Christian Couder在本文中的 "Bisection算法"部分."检查合并基础"部分也可能是相关的.
• 如上所述,问题当然是使用与我使用的版本不同的版本(问题来自2013年,Git 2.11来自2016年).

Bisect运行输出

• 请注意,首先选中"添加管理员通知"(第4行),因为它提供了最多的信息.(阅读上述文章中的"检查合并基础".)
• 从那时起,它将线性历史一分为二.

# bad: [d7761d6f146eaca1d886f793ced4315539326866] Add data escaping. (Bad)
# good: [f555d9063a25a20a6ec7c3b0c0504ffe0a997e98] Add Responsive Nav. (Good)
git bisect start 'd7761d6f146eaca1d886f793ced4315539326866' 'f555d9063a25a20a6ec7c3b0c0504ffe0a997e98'
# good: [1b3b7f4952732fec0c68a37d5f313d6f4219e4ae] Add ‘Admin’ notice. (Good)
git bisect good 1b3b7f4952732fec0c68a37d5f313d6f4219e4ae
# bad: [f9a65fe9e6cde4358e5b8ef7569332abfb07675e] Add icons. (Bad)
git bisect bad f9a65fe9e6cde4358e5b8ef7569332abfb07675e
# bad: [165b8a6e5137c40ce8b90911e59d7ec8eec30f46] Add menu styles. (Bad)
git bisect bad 165b8a6e5137c40ce8b90911e59d7ec8eec30f46
# first bad commit: [165b8a6e5137c40ce8b90911e59d7ec8eec30f46] Add menu styles. (Bad)

码

使用Git 2.11.0 在Python 3中运行.要运行的命令:python3 script.py

""" The following code creates a git repository in '/tmp/git-repo' and populates
it with the following commit graph. Each commit has a test.sh which can be used
as input to a git-bisect-run.

The code then tries to find the breaking change automatically.
And prints out the git bisect log.

Written in response to http://stackoverflow.com/questions/17267816/git-bisect-with-merged-commits
to test the claim that '107ca95..3e667f8 are never checked out'.

Needs Python 3!
"""


from itertools import chain
import os.path
import os
import sh

repo = {
0x3830e61:  {'message': "Add data escaping.", 'parents': [    0x0f5e148    ], 'test': False} , # Last:    (Bad)
0x0f5e148: {'message': "Improve function for getting page template.", 'parents': [ 0xaaf8dc5], 'test': False},
0xaaf8dc5: {'message': "Merge branch 'navigation'", 'parents': [ 0x3e667f8, 0xea3d736], 'test': False},
    0x3e667f8: {'message': "Add icons.", 'parents': [  0x43a07b1], 'test': False},
    0x43a07b1: {'message': "Add menu styles.", 'parents': [    0x107ca95], 'test': False}  , # First:       (Breaks)
    0x107ca95: {'message': "Add Responsive Nav.", 'parents': [   0xf52cc34], 'test': True}, # First:        (Good)
  0xea3d736: {'message': "Add ‘Admin’ notice.", 'parents': [ 0x17ca0bb], 'test': True},
  0x17ca0bb: {'message': "Update placeholder text.", 'parents': [  0xf52cc34], 'test': True},
0xf52cc34: {'message': "Add featured image.", 'parents': [  0x2abd954], 'test': True},
0x2abd954: {'message': "Style placeholders.", 'parents': [], 'test': True},
}

bad = 0x3830e61
good = 0x107ca95


def generate_queue(_dag, parents):
    for prev in parents:
        yield prev
        yield from generate_queue(_dag, _dag[prev]['parents'])

def make_queue(_dag, inits):
    """ Converts repo (a DAG) into a queue """
    q = list(generate_queue(_dag, inits))
    q.reverse()
    seen = set()
    r = [x for x in q if not (x in seen or seen.add(x))]
    return r

if __name__ == '__main__':
    pwd = '/tmp/git-repo'
    sh.rm('-r', pwd)
    sh.mkdir('-p', pwd)
    g = sh.git.bake(_cwd=pwd)
    g.init()

    parents = set(chain.from_iterable((repo[c]['parents'] for c in repo)))

    commits = set(repo)
    inits = list(commits - parents)
    queue = make_queue(repo, inits)

    assert len(queue) == len(repo), "queue {} vs repo {}".format(len(queue), len(repo))

    commit_ids = {}
    # Create commits
    for c in queue:
        # Set up repo
        parents = repo[c]['parents']
        if len(parents) > 0:
            g.checkout(commit_ids[parents[0]])
        if len(parents) > 1:
            if len(parents) > 2: raise NotImplementedError('Octopus merges not support yet.')
            g.merge('--no-commit', '-s', 'ours', commit_ids[parents[1]])  # just force to use 'ours' strategy.

        # Make changes
        with open(os.path.join(pwd, 'test.sh'), 'w') as f:
            f.write('exit {:d}\n'.format(0 if repo[c]['test'] else 1))
        os.chmod(os.path.join(pwd, 'test.sh'), 0o0755)
        with open(os.path.join(pwd, 'message'), 'w') as f:
            f.write(repo[c]['message'])
        g.add('test.sh', 'message')
        g.commit('-m', '{msg} ({test})'.format(msg=repo[c]['message'], test='Good' if repo[c]['test'] else 'Bad'))
        commit_ids[c] = g('rev-parse', 'HEAD').strip()

    # Run git-bisect
    g.bisect('start', commit_ids[bad], commit_ids[good])
    g.bisect('run', './test.sh')
    print(g.bisect('log'))

Answer 2

这已经回答了

基本想法 - 要找到功能分支中的哪个提交会破坏您的主人,您将不得不在ea3d736 - 相关主HEAD之上重新应用它.

以下是测试脚本的一个示例(来自git doc),它为您执行此操作:

$ cat ~/test.sh
#!/bin/sh

# tweak the working tree by merging the hot-fix branch
# and then attempt a build
if  git merge --no-commit ea3d736 &&
    make
then
    # run project specific test and report its status
    ~/check_test_case.sh
    status=$?
else
    # tell the caller this is untestable
    status=125
fi

# undo the tweak to allow clean flipping to the next commit
git reset --hard

# return control
exit $status

运行:

git bisect start 3830e61 f52cc34 
git bisect good ea3d736 17ca0bb #If you want to test feature branch only
git bisect run ~/test.sh

Answer 3

您可以使用“git start”命令选择提交范围。该命令的概要是：

git bisect start <bad> <good>

在你的具体情况下，我认为正确的命令是：

git bisect start 3830e61 107ca95