
from IPython.display import display, Code
import tempfile
from pathlib import PurePath
import os
import subprocess
import shlex
import hashlib
import zlib
import time
import shutil
from typing import Optional, List
from display_git import display_tree, display_general


base = tempfile.mkdtemp(prefix='git-mock-')

print(f'explore git at {base}')

explore git at /tmp/git-mock-xma7sdir


"""
执行 shell 命令，将结果展示出来

主要用来验证模拟的结果
"""
def run_cmd(cmd):
    proc = subprocess.run(shlex.split(cmd), capture_output=True, encoding='utf-8')

    display(Code(f'>>> {shlex.join(proc.args)}\n{proc.stdout or proc.stderr}'))


run_cmd('git --version')

>>> git --version
git version 2.25.1


git_dir = PurePath(base).joinpath('.git')
os.mkdir(git_dir)

for d in ['refs/heads', 'objects']:
    os.makedirs(git_dir.joinpath(d), exist_ok=True)

with open(git_dir.joinpath('config'), 'wt', encoding='utf-8') as f:
    f.write('''\
[core]
    repositoryformatversion = 0
    filemode = true
    bare = false
    logallrefupdates = false
''')
    
with open(git_dir.joinpath('HEAD'), 'wt', encoding='utf-8') as f:
    f.write('ref: refs/heads/master')


run_cmd(f'tree {base} -a')

>>> tree /tmp/git-mock-xma7sdir -a
/tmp/git-mock-xma7sdir
└── .git
    ├── config
    ├── HEAD
    ├── objects
    └── refs
        └── heads

4 directories, 2 files


run_cmd(f'git -C {base} status')

>>> git -C /tmp/git-mock-xma7sdir status
On branch master

No commits yet

nothing to commit (create/copy files and use "git add" to track)


py_v1_text = 'print("hello")\n'
py_file_name = 'hello.py'
with open(os.path.join(base, py_file_name), 'wt', encoding='utf-8') as f:
    f.write(py_v1_text)


run_cmd(f'tree {base} -a')

>>> tree /tmp/git-mock-xma7sdir -a
/tmp/git-mock-xma7sdir
├── .git
│   ├── config
│   ├── HEAD
│   ├── objects
│   └── refs
│       └── heads
└── hello.py

4 directories, 3 files


run_cmd(f'git -C {base} status')

>>> git -C /tmp/git-mock-xma7sdir status
On branch master

No commits yet

Untracked files:
  (use "git add <file>..." to include in what will be committed)
	hello.py

nothing added to commit but untracked files present (use "git add" to track)


"""
将文件内容经过zlib压缩后，写入 `.git/object/` 文件夹

文件的命名方式是：
- 取 sha 的前两位作为文件夹名
- 取 sha 的剩下位数作为文件名
"""
def write_object(raw_content: bytes, sha1: str, git_dir: PurePath) -> None:
    compressed = zlib.compress(raw_content)
    object_dir = git_dir.joinpath('objects', sha1[:2])
    os.makedirs(object_dir, exist_ok=True)
    with open(object_dir.joinpath(sha1[2:]), 'wb') as f:
        f.write(compressed)


"""
写 blob object, 模拟 `git add` 的第一部分操作

blob object 的 
- <ascii type> = blob
- <binary object data> = 要 add 的文件的内容
"""
def write_blob_object(file_content: str) -> str:
    raw_content = f'blob {len(file_content)}\0{file_content}'.encode('utf-8')
    sha1 = hashlib.sha1(raw_content).hexdigest()
    
    write_object(raw_content, sha1, git_dir)
        
    return sha1


with open(os.path.join(base, py_file_name), 'rt', encoding='utf-8') as f:
    file_content = f.read()
    
py_v1_blob_sha = write_blob_object(file_content)
print(py_v1_blob_sha)

11b15b1a4584b08fa423a57964bdbf018b0da0d5


run_cmd(f'git -C {base} cat-file -p {py_v1_blob_sha}')

>>> git -C /tmp/git-mock-xma7sdir cat-file -p 11b15b1a4584b08fa423a57964bdbf018b0da0d5
print("hello")


run_cmd(f'tree {base} -a')

>>> tree /tmp/git-mock-xma7sdir -a
/tmp/git-mock-xma7sdir
├── .git
│   ├── config
│   ├── HEAD
│   ├── objects
│   │   └── 11
│   │       └── b15b1a4584b08fa423a57964bdbf018b0da0d5
│   └── refs
│       └── heads
└── hello.py

5 directories, 4 files


run_cmd(f'git -C {base} status')

>>> git -C /tmp/git-mock-xma7sdir status
On branch master

No commits yet

Untracked files:
  (use "git add <file>..." to include in what will be committed)
	hello.py

nothing added to commit but untracked files present (use "git add" to track)


"""
ref: https://git-scm.com/docs/index-format/2.25.0#_index_entry
"""
class IndexEntry:
    def __init__(self, path: str, blob_sha: str, base_path: str):
        self.path = path
        self.blob_sha = blob_sha
        self.base_path = base_path
    
    def to_bytes(self):
        stat = os.stat(self.path)
        
        b = int(stat.st_ctime).to_bytes(4, byteorder='big')
        b += int(stat.st_ctime_ns % 1e9).to_bytes(4, byteorder='big')
        b += int(stat.st_mtime).to_bytes(4, byteorder='big')
        b += int(stat.st_mtime_ns % 1e9).to_bytes(4, byteorder='big')
        
        b += int(stat.st_dev).to_bytes(4, byteorder='big')
        b += int(stat.st_ino).to_bytes(4, byteorder='big')
        b += int('100644', 8).to_bytes(4, byteorder='big')
        b += int(stat.st_uid).to_bytes(4, byteorder='big')
        b += int(stat.st_gid).to_bytes(4, byteorder='big')
        b += int(stat.st_size).to_bytes(4, byteorder='big')
        
        b += bytes.fromhex(self.blob_sha)
        
        assume_valid_flag = 0 << 3
        extended_flag = 0 << 2
        merge_stage_flag = 0
        name_length = len(os.path.basename(self.path)) \
            if len(os.path.basename(self.path)) < 0xfff else 0xfff
        flags = (
            ((assume_valid_flag | extended_flag | merge_stage_flag) << 12) 
            | name_length
        ).to_bytes(2, byteorder='big')
        b += flags
        
        relative_path_name = os.path.relpath(self.path, self.base_path).encode('utf-8')
        b += relative_path_name
        
        padding_size = 8 - (len(b) % 8)
        b += (b'\0' * padding_size)
        
        return b


"""
写 index file, 模拟 `git add` 第二部分操作
"""
def write_index_file(entries: List[IndexEntry]) -> None:
    signature = b'DIRC'
    version = (2).to_bytes(4, byteorder='big')
    entries_number = len(entries).to_bytes(4, byteorder='big')
    
    # Index entries are sorted in ascending order on the name field
    entries = sorted(entries, key=lambda e: e.path)
    raw_content = signature + version + entries_number \
        + b''.join([e.to_bytes() for e in entries])
    sha1 = hashlib.sha1(raw_content).hexdigest()
    raw_content += bytes.fromhex(sha1)
    
    with open(git_dir.joinpath('index'), 'wb') as f:
        f.write(raw_content)


py_v1_index_entry = IndexEntry(
    path=os.path.join(base, py_file_name), 
    blob_sha=py_v1_blob_sha, 
    base_path=base)
write_index_file([py_v1_index_entry])


run_cmd(f'tree {base} -a')

>>> tree /tmp/git-mock-xma7sdir -a
/tmp/git-mock-xma7sdir
├── .git
│   ├── config
│   ├── HEAD
│   ├── index
│   ├── objects
│   │   └── 11
│   │       └── b15b1a4584b08fa423a57964bdbf018b0da0d5
│   └── refs
│       └── heads
└── hello.py

5 directories, 5 files


run_cmd(f'git -C {base} status')

>>> git -C /tmp/git-mock-xma7sdir status
On branch master

No commits yet

Changes to be committed:
  (use "git rm --cached <file>..." to unstage)
	new file:   hello.py


"""
tree object 里每个条目的结构

`<mode> <object_type> <sha>\t<name>`
"""
class TreeEntry:
    def __init__(self, object_type: str, name: str, sha: str):
        assert(object_type in ('tree', 'blob', 'commit', 'tag'))
        self.object_type = object_type
        self.name = name
        self.sha = sha
        self.mode = '100644' if object_type == 'blob' else '40000'


"""
写入 tree object, 模拟 `git commit` 的第一部分操作

tree object 的 
- <ascii type> = tree
- <binary object data> = sorted tree entries
"""
def write_tree_object(entries: List[TreeEntry]) -> str:
    sorted_entries = sorted(entries, key=lambda e: e.name)
    
    entries_content = b''.join([
        f'{e.mode} {e.name}\0'.encode('utf-8') + bytes.fromhex(e.sha) 
        for e in sorted_entries
    ])
    raw_content = f'tree {len(entries_content)}\0'.encode('utf-8') + entries_content
    sha1 = hashlib.sha1(raw_content).hexdigest()
    
    write_object(raw_content, sha1, git_dir)
    
    return sha1


py_tree_entry = TreeEntry(object_type='blob', name=py_file_name, sha=py_v1_blob_sha)
first_tree_sha = write_tree_object([py_tree_entry])
print(first_tree_sha)

30ffe02680eefd02f7ada864196baaade119243b


run_cmd(f'git -C {base} cat-file -p {first_tree_sha}')

>>> git -C /tmp/git-mock-xma7sdir cat-file -p 30ffe02680eefd02f7ada864196baaade119243b
100644 blob 11b15b1a4584b08fa423a57964bdbf018b0da0d5	hello.py


run_cmd(f'tree {base} -a')

>>> tree /tmp/git-mock-xma7sdir -a
/tmp/git-mock-xma7sdir
├── .git
│   ├── config
│   ├── HEAD
│   ├── index
│   ├── objects
│   │   ├── 11
│   │   │   └── b15b1a4584b08fa423a57964bdbf018b0da0d5
│   │   └── 30
│   │       └── ffe02680eefd02f7ada864196baaade119243b
│   └── refs
│       └── heads
└── hello.py

6 directories, 6 files


display_tree(tree_sha=first_tree_sha, base_path=base, width='200px')


run_cmd(f'git -C {base} status')

>>> git -C /tmp/git-mock-xma7sdir status
On branch master

No commits yet

Changes to be committed:
  (use "git rm --cached <file>..." to unstage)
	new file:   hello.py


my_name = 'Soros Liu'
my_email = '[email protected]'

"""
写入 commit object, 模拟 `git commit` 的第二部分操作

commit object 的 
- <ascii type> = commit
- <binary object data> = 见下

binary object data 的格式如下：

```
tree <tree_sha>
parent <parent_commmit_sha>
author <author_name> <author_email> <timestamp>
committer <committer_name> <committer_email> <timestamp>

<commit_message>
```
"""
def write_commit_object(tree_sha: str, parent_commmit_sha: Optional[str], msg: str) -> str:
    commit = f'tree {tree_sha}\n' + \
        (f'parent {parent_commmit_sha}\n' if parent_commmit_sha else '') + \
        f'author {my_name} <{my_email}> {int(time.time())} +0800\n' + \
        f'committer {my_name} <{my_email}> {int(time.time())} +0800\n' + \
        '\n' + \
        msg + \
        '\n'
    
    commit_content = commit.encode('utf-8')
    raw_content = f'commit {len(commit_content)}\0'.encode('utf-8') + commit_content
    sha1 = hashlib.sha1(raw_content).hexdigest()
    
    write_object(raw_content, sha1, git_dir)
    
    return sha1


first_commit_sha = write_commit_object(
    tree_sha=first_tree_sha, 
    parent_commmit_sha=None, 
    msg='first commit')
print(first_commit_sha)

5b28d3c9988aa1427fe3afe6515869672ef50884


run_cmd(f'git -C {base} cat-file -p {first_commit_sha}')

>>> git -C /tmp/git-mock-xma7sdir cat-file -p 5b28d3c9988aa1427fe3afe6515869672ef50884
tree 30ffe02680eefd02f7ada864196baaade119243b
author Soros Liu <soros.liu1029@gmail.com> 1635143887 +0800
committer Soros Liu <soros.liu1029@gmail.com> 1635143887 +0800

first commit


run_cmd(f'tree {base} -a')

>>> tree /tmp/git-mock-xma7sdir -a
/tmp/git-mock-xma7sdir
├── .git
│   ├── config
│   ├── HEAD
│   ├── index
│   ├── objects
│   │   ├── 11
│   │   │   └── b15b1a4584b08fa423a57964bdbf018b0da0d5
│   │   ├── 30
│   │   │   └── ffe02680eefd02f7ada864196baaade119243b
│   │   └── 5b
│   │       └── 28d3c9988aa1427fe3afe6515869672ef50884
│   └── refs
│       └── heads
└── hello.py

7 directories, 7 files


run_cmd(f'git -C {base} status')

>>> git -C /tmp/git-mock-xma7sdir status
On branch master

No commits yet

Changes to be committed:
  (use "git rm --cached <file>..." to unstage)
	new file:   hello.py


run_cmd(f'git -C {base} log')

>>> git -C /tmp/git-mock-xma7sdir log
fatal: your current branch 'master' does not have any commits yet


run_cmd(f'cat {base}/.git/HEAD')

>>> cat /tmp/git-mock-xma7sdir/.git/HEAD
ref: refs/heads/master


with open(git_dir.joinpath('refs', 'heads', 'master'), 'wt', encoding='utf-8') as f:
    f.write(first_commit_sha)


run_cmd(f'tree {base} -a')

>>> tree /tmp/git-mock-xma7sdir -a
/tmp/git-mock-xma7sdir
├── .git
│   ├── config
│   ├── HEAD
│   ├── index
│   ├── objects
│   │   ├── 11
│   │   │   └── b15b1a4584b08fa423a57964bdbf018b0da0d5
│   │   ├── 30
│   │   │   └── ffe02680eefd02f7ada864196baaade119243b
│   │   └── 5b
│   │       └── 28d3c9988aa1427fe3afe6515869672ef50884
│   └── refs
│       └── heads
│           └── master
└── hello.py

7 directories, 8 files


run_cmd(f'git -C {base} status')

>>> git -C /tmp/git-mock-xma7sdir status
On branch master
nothing to commit, working tree clean


run_cmd(f'git -C {base} log')

>>> git -C /tmp/git-mock-xma7sdir log
commit 5b28d3c9988aa1427fe3afe6515869672ef50884
Author: Soros Liu <soros.liu1029@gmail.com>
Date:   Mon Oct 25 14:38:07 2021 +0800

    first commit


md_text = '## Explore Python\n'
md_file_name = 'README.md'
with open(os.path.join(base, md_file_name), 'wt', encoding='utf-8') as f:
    f.write(md_text)


run_cmd(f'git -C {base} status')

>>> git -C /tmp/git-mock-xma7sdir status
On branch master
Untracked files:
  (use "git add <file>..." to include in what will be committed)
	README.md

nothing added to commit but untracked files present (use "git add" to track)


with open(os.path.join(base, md_file_name), 'rt', encoding='utf-8') as f:
    file_content = f.read()
    
md_blob_sha = write_blob_object(file_content)
print(md_blob_sha)

799edde33b434795e10848fbd25bbba1d102c44f


run_cmd(f'git -C {base} status')

>>> git -C /tmp/git-mock-xma7sdir status
On branch master
Untracked files:
  (use "git add <file>..." to include in what will be committed)
	README.md

nothing added to commit but untracked files present (use "git add" to track)


run_cmd(f'tree {base} -a')

>>> tree /tmp/git-mock-xma7sdir -a
/tmp/git-mock-xma7sdir
├── .git
│   ├── config
│   ├── HEAD
│   ├── index
│   ├── objects
│   │   ├── 11
│   │   │   └── b15b1a4584b08fa423a57964bdbf018b0da0d5
│   │   ├── 30
│   │   │   └── ffe02680eefd02f7ada864196baaade119243b
│   │   ├── 5b
│   │   │   └── 28d3c9988aa1427fe3afe6515869672ef50884
│   │   └── 79
│   │       └── 9edde33b434795e10848fbd25bbba1d102c44f
│   └── refs
│       └── heads
│           └── master
├── hello.py
└── README.md

8 directories, 10 files


md_index_entry = IndexEntry(
    path=os.path.join(base, md_file_name), 
    blob_sha=md_blob_sha, 
    base_path=base)
write_index_file([py_v1_index_entry, md_index_entry])


run_cmd(f'git -C {base} status')

>>> git -C /tmp/git-mock-xma7sdir status
On branch master
Changes to be committed:
  (use "git restore --staged <file>..." to unstage)
	new file:   README.md


md_tree_entry = TreeEntry(object_type='blob', name=md_file_name, sha=md_blob_sha)
second_tree_sha = write_tree_object([py_tree_entry, md_tree_entry])
print(second_tree_sha)

0ba40bfddcda73cf6ce598e82b4d3de9d0cc7065


run_cmd(f'git -C {base} cat-file -p {second_tree_sha}')

>>> git -C /tmp/git-mock-xma7sdir cat-file -p 0ba40bfddcda73cf6ce598e82b4d3de9d0cc7065
100644 blob 799edde33b434795e10848fbd25bbba1d102c44f	README.md
100644 blob 11b15b1a4584b08fa423a57964bdbf018b0da0d5	hello.py


run_cmd(f'tree {base} -a')

>>> tree /tmp/git-mock-xma7sdir -a
/tmp/git-mock-xma7sdir
├── .git
│   ├── config
│   ├── HEAD
│   ├── index
│   ├── objects
│   │   ├── 0b
│   │   │   └── a40bfddcda73cf6ce598e82b4d3de9d0cc7065
│   │   ├── 11
│   │   │   └── b15b1a4584b08fa423a57964bdbf018b0da0d5
│   │   ├── 30
│   │   │   └── ffe02680eefd02f7ada864196baaade119243b
│   │   ├── 5b
│   │   │   └── 28d3c9988aa1427fe3afe6515869672ef50884
│   │   └── 79
│   │       └── 9edde33b434795e10848fbd25bbba1d102c44f
│   └── refs
│       └── heads
│           └── master
├── hello.py
└── README.md

9 directories, 11 files


display_tree(tree_sha=second_tree_sha, base_path=base, width='500px')


second_commit_sha = write_commit_object(
    tree_sha=second_tree_sha, 
    parent_commmit_sha=first_commit_sha, 
    msg='second commit')
print(second_commit_sha)

e9e5df04ab501bec4525967eac89d1bb29c425d3


run_cmd(f'git -C {base} cat-file -p {second_commit_sha}')

>>> git -C /tmp/git-mock-xma7sdir cat-file -p e9e5df04ab501bec4525967eac89d1bb29c425d3
tree 0ba40bfddcda73cf6ce598e82b4d3de9d0cc7065
parent 5b28d3c9988aa1427fe3afe6515869672ef50884
author Soros Liu <soros.liu1029@gmail.com> 1635143888 +0800
committer Soros Liu <soros.liu1029@gmail.com> 1635143888 +0800

second commit


run_cmd(f'tree {base} -a')

>>> tree /tmp/git-mock-xma7sdir -a
/tmp/git-mock-xma7sdir
├── .git
│   ├── config
│   ├── HEAD
│   ├── index
│   ├── objects
│   │   ├── 0b
│   │   │   └── a40bfddcda73cf6ce598e82b4d3de9d0cc7065
│   │   ├── 11
│   │   │   └── b15b1a4584b08fa423a57964bdbf018b0da0d5
│   │   ├── 30
│   │   │   └── ffe02680eefd02f7ada864196baaade119243b
│   │   ├── 5b
│   │   │   └── 28d3c9988aa1427fe3afe6515869672ef50884
│   │   ├── 79
│   │   │   └── 9edde33b434795e10848fbd25bbba1d102c44f
│   │   └── e9
│   │       └── e5df04ab501bec4525967eac89d1bb29c425d3
│   └── refs
│       └── heads
│           └── master
├── hello.py
└── README.md

10 directories, 12 files


run_cmd(f'git -C {base} status')

>>> git -C /tmp/git-mock-xma7sdir status
On branch master
Changes to be committed:
  (use "git restore --staged <file>..." to unstage)
	new file:   README.md


with open(git_dir.joinpath('refs', 'heads', 'master'), 'wt', encoding='utf-8') as f:
    f.write(second_commit_sha)


run_cmd(f'git -C {base} status')

>>> git -C /tmp/git-mock-xma7sdir status
On branch master
nothing to commit, working tree clean


run_cmd(f'git -C {base} log')

>>> git -C /tmp/git-mock-xma7sdir log
commit e9e5df04ab501bec4525967eac89d1bb29c425d3
Author: Soros Liu <soros.liu1029@gmail.com>
Date:   Mon Oct 25 14:38:08 2021 +0800

    second commit

commit 5b28d3c9988aa1427fe3afe6515869672ef50884
Author: Soros Liu <soros.liu1029@gmail.com>
Date:   Mon Oct 25 14:38:07 2021 +0800

    first commit


run_cmd(f'cat {base}/.git/HEAD')
run_cmd(f'git -C {base} branch --show-current')
run_cmd(f'git -C {base} rev-parse HEAD')

>>> cat /tmp/git-mock-xma7sdir/.git/HEAD
ref: refs/heads/master

>>> git -C /tmp/git-mock-xma7sdir branch --show-current
master

>>> git -C /tmp/git-mock-xma7sdir rev-parse HEAD
e9e5df04ab501bec4525967eac89d1bb29c425d3


shutil.copy(
    git_dir.joinpath('refs', 'heads', 'master'), 
    git_dir.joinpath('refs', 'heads', 'new-idea')
)

with open(git_dir.joinpath('HEAD'), 'wt', encoding='utf-8') as f:
    f.write('ref: refs/heads/new-idea')


run_cmd(f'git -C {base} branch --show-current')
run_cmd(f'git -C {base} rev-parse HEAD')
run_cmd(f'git -C {base} log --oneline --decorate --graph')

>>> git -C /tmp/git-mock-xma7sdir branch --show-current
new-idea

>>> git -C /tmp/git-mock-xma7sdir rev-parse HEAD
e9e5df04ab501bec4525967eac89d1bb29c425d3

>>> git -C /tmp/git-mock-xma7sdir log --oneline --decorate --graph
* e9e5df0 (HEAD -> new-idea, master) second commit
* 5b28d3c first commit


py_v2_text = 'print("hello world")\n'
with open(os.path.join(base, py_file_name), 'wt', encoding='utf-8') as f:
    f.write(py_v2_text)


run_cmd(f'git -C {base} status')

>>> git -C /tmp/git-mock-xma7sdir status
On branch new-idea
Changes not staged for commit:
  (use "git add <file>..." to update what will be committed)
  (use "git restore <file>..." to discard changes in working directory)
	modified:   hello.py

no changes added to commit (use "git add" and/or "git commit -a")


run_cmd(f'git -C {base} diff')

>>> git -C /tmp/git-mock-xma7sdir diff
diff --git a/hello.py b/hello.py
index 11b15b1..8cde782 100644
--- a/hello.py
+++ b/hello.py
@@ -1 +1 @@
-print("hello")
+print("hello world")


with open(os.path.join(base, py_file_name), 'rt', encoding='utf-8') as f:
    file_content = f.read()
    
py_v2_blob_sha = write_blob_object(file_content)
print(py_v2_blob_sha)

8cde7829c178ede96040e03f17c416d15bdacd01


py_v2_index_entry = IndexEntry(
    path=os.path.join(base, py_file_name), 
    blob_sha=py_v2_blob_sha, 
    base_path=base)
write_index_file([py_v2_index_entry, md_index_entry])


run_cmd(f'git -C {base} status')

>>> git -C /tmp/git-mock-xma7sdir status
On branch new-idea
Changes to be committed:
  (use "git restore --staged <file>..." to unstage)
	modified:   hello.py


py_tree_entry = TreeEntry(object_type='blob', name=py_file_name, sha=py_v2_blob_sha)
third_tree_sha = write_tree_object([py_tree_entry, md_tree_entry])
print('tree sha:', third_tree_sha)

third_commit_sha = write_commit_object(
    tree_sha=third_tree_sha, 
    parent_commmit_sha=second_commit_sha, 
    msg='third commit')
print('commit sha:', third_commit_sha)

with open(git_dir.joinpath('refs', 'heads', 'new-idea'), 'wt', encoding='utf-8') as f:
    f.write(third_commit_sha)

tree sha: b2c193ca98949e609761b7302867b33b81be3242
commit sha: e546bf5191299064c4005517ffa21da992f23401


run_cmd(f'git -C {base} status')
run_cmd(f'git -C {base} log --oneline --decorate --graph')

>>> git -C /tmp/git-mock-xma7sdir status
On branch new-idea
nothing to commit, working tree clean

>>> git -C /tmp/git-mock-xma7sdir log --oneline --decorate --graph
* e546bf5 (HEAD -> new-idea) third commit
* e9e5df0 (master) second commit
* 5b28d3c first commit


display_general(base_path=base, width='100%')


shutil.copy(
    git_dir.joinpath('refs', 'heads', 'new-idea'), 
    git_dir.joinpath('refs', 'heads', 'master')
);


run_cmd(f'git -C {base} log --oneline --decorate --graph')

>>> git -C /tmp/git-mock-xma7sdir log --oneline --decorate --graph
* e546bf5 (HEAD -> new-idea, master) third commit
* e9e5df0 second commit
* 5b28d3c first commit

Git 的无实物表演¶

aka: Play like Git without Git¶

Git 是什么¶

在这里想做的事：¶

git init¶

git add¶

git commit¶

bookmark¶

版本控制¶

git checkout -b¶

git merge¶