Version: $Revision$
Last-Modified: $Date$
Author: Oleg Broytman <phd@phdru.name>
-Status: Active
+Status: Draft
Type: Informational
Content-Type: text/x-rst
Created: 01-Jun-2015
`Git workflows
<https://www.kernel.org/pub/software/scm/git/docs/gitworkflows.html>`_.
+Advanced documentation
+----------------------
+
`Git Magic
<http://www-cs-students.stanford.edu/~blynn/gitmagic/index.html>`_,
also with a number of translations.
-Advanced documentation
-----------------------
-
`Pro Git <https://git-scm.com/book>`_. The Book about git. Buy it at
Amazon or download in PDF, mobi, or ePub form. Has translations to
many different languages. Download Russian translation from `GArik
<http://sourceforge.net/projects/git-osx-installer/files/>`_ or
install git with `Homebrew <http://brew.sh/>`_: ``brew install git``.
-`Atlassins's SourceTree <https://www.sourcetreeapp.com/>`_ is a free
-Git and Mercurial GUI client for Windows or Mac.
+`git-cola <https://git-cola.github.io/index.html>`_ is a Git GUI
+written in Python and GPL licensed. Linux, Windows, MacOS X.
+
+`TortoiseGit <https://tortoisegit.org/>`_ is a Windows Shell Interface
+to Git based on TortoiseSVN; open source.
Initial configuration
---------------------
This simple code is often appears in documentation, but it is
-important so let repeat it here. Git marks every commit with author
-and committer names/emails, so configure your real name and preferred
-email::
+important so let repeat it here. Git stores author and committer
+names/emails in every commit, so configure your real name and
+preferred email::
$ git config --global user.name "User Name"
$ git config --global user.email user.name@example.org
$ cd python
$ git branch v1 origin/v1
+The first command clones remote repository into local directory
+`python``, creates a new local branch v2, sets remotes/origin/v2 as
+its upstream remote branch and checks it out into the working
+directory.
+
The last command creates a new local branch v1 and sets
remotes/origin/v1 as its upstream remote branch.
-The same result can achieved with commands::
+The same result can be achieved with commands::
$ git clone -b v1 http://git.python.org/python.git
$ cd python
freely.
-Remote repository and remote branches
-=====================================
+Remote repositories and remote branches
+=======================================
Another example of slightly misleading terminology. Remote
repositories are really remote, you access them via network (well, a
You never do your own development on remote branches. You create a
local branch that has a remote branch as upstream and do development
-on that local branch. On push git updates remote branches, and on pull
-git updates remote branches and fast-forwards, merges or rebases local
-branches.
+on that local branch. On push git pushes commits to the remote repo
+and updates remote branches, on pull git fetches commits from the
+remote repo, updates remote branches and fast-forwards, merges or
+rebases local branches.
When you do an initial clone like this::
::
$ git fetch REMOTE BRANCH
- $ git merge FETCH_HEAD # FETCH_HEAD is a literal here
+ $ git merge FETCH_HEAD # FETCH_HEAD is a literal here
Certainly, BRANCH in that case should be your current branch. If you
want to merge a different branch into your current branch first update
that non-current branch and then merge::
- $ git fetch origin v1:v1 # Update v1
- $ git pull --rebase origin v2 # Update the current branch v2 using
- # rebase instead of merge
+ $ git fetch origin v1:v1 # Update v1
+ $ git pull --rebase origin v2 # Update the current branch v2 using
+ # rebase instead of merge
+ $ git merge v1
+
+If you have not yet pushed commits on ``v1``, though, the scenario has
+to become a bit more complex. Git refuses to update
+non-fast-forwardable branch, and you don't want to do force-pull
+because that would remove your non-pushed commits and you would need
+to recover. So you want to rebase ``v1`` but you cannot rebase
+non-current branch. Hence, checkout ``v1`` and rebase it before
+merging::
+
+ $ git checkout v1
+ $ git pull --rebase origin v1
+ $ git checkout v2
+ $ git pull --rebase origin v2
$ git merge v1
It is possible to configure git to make it fetch/pull a few branches
Undo
====
-TODO: describe undo strategies: git reset, git revert, git checkout,
-git reflog. "Commit early, commit often".
+Whatever you do, don't panic. Almost anything in git can be undone.
+``git checkout``, for example, can be used to restore the content of
+file(s) to that one of a commit. Like this::
+
+ git checkout HEAD~ README
+
+The commands restores the contente of README file to the last but one
+commit in the current branch. By default a commit ID is simple HEAD;
+i.e. ``git checkout README`` restores README to the latest commit.
+
+(Do not use ``git checkout`` to view a content of a file in a commit,
+use ``git cat-file -p``; e.g. ``git cat-file -p HEAD~:path/to/README``).
+
+``git reset`` moves the head of the current branch. The head can be
+moved to point to any commit but it's often used to remove a commit or
+a few (preferably, non-pushed ones) from the top of the branch - that
+is, to move the branch backward in order to undo a few non-pushed
+commits.
+
+``git reset`` has three modes of operation - soft, hard and mixed.
+Default is mixed. ProGit `explains
+<https://git-scm.com/book/en/Git-Tools-Reset-Demystified>`_ the
+difference very clearly. Bare repositories don't have indices or
+working trees so in a bare repo only soft reset is possible.
+
+Mixed mode reset with a path or paths can be used to unstage changes -
+that is, to remove changes added with ``git add`` for committing. See
+`The Book <https://git-scm.com/book/en/v2/Git-Basics-Undoing-Things>`_
+for details about unstaging and other undo tricks.
+
+TODO: describe undo strategies: git reflog, git revert.
+"Commit early, commit often".
How to undo a merge
-https://kernel.org/pub/software/scm/git/docs/howto/revert-a-faulty-merge.html
+https://www.kernel.org/pub/software/scm/git/docs/howto/revert-a-faulty-merge.html
Merge or rebase?
================
+Internet is full of heated discussions on the topic: "merge or
+rebase?" Most of them are meaningless. When a DVCS is being used in a
+big team with a big and complex project with many branches there is
+simply no way to avoid merges. So the question's diminished to
+"whether to use rebase, and if yes - when to use rebase?" Considering
+that it is very much recommended not to rebase published commits the
+question's diminished even further: "whether to use rebase on
+non-pushed commits?"
+
+That small question is for the team to decide. The author of the PEP
+recommends to use rebase when pulling, i.e. always do ``git pull
+--rebase`` or even configure automatic setup of rebase for every new
+branch::
+
+ $ git config branch.autosetuprebase always
+
+and configure rebase for existing branches::
+
+ $ git config branch.NAME.rebase true
+
+For example::
+
+ $ git config branch.v1.rebase true
+ $ git config branch.v2.rebase true
+
+After that ``git pull origin v2`` becomes equivalent to ``git pull
+--rebase origin v2``.
+
+In case when merge is preferred it is recommended to create new
+commits in a separate feature or topic branch while using rebase to
+update the mainline branch. When the topic branch is ready merge it
+into mainline. To avoid a tedious task of resolving large number of
+conflicts at once you can merge the topic branch to the mainline from
+time to time and switch back to the topic branch to continue working
+on it. The entire workflow would be something like::
+
+ $ git checkout -b issue-42 # create a new issue branch and switch to it
+ ...edit/test/commit...
+ $ git checkout v2
+ $ git pull --rebase origin v2 # update v2 from the upstream
+ $ git merge issue-42
+ $ git branch -d issue-42 # delete the topic branch
+ $ git push origin v2
+
+When the topic branch is deleted only the label is removed, commits
+are stayed in the database, they are now merged into v2::
+
+ o--o--o--o--o--M--< v2 - the mainline branch
+ \ /
+ --*--*--* - the topic branch, now unnamed
+
+The topic branch is deleted to avoid cluttering branch namespace with
+small topic branches. Information on what issue was fixed or what
+feature was implemented should be in the commit messages.
+
Null-merges
===========
-Git has a builtin strategy for what Python core developers call
+Git has a builtin merge strategy for what Python core developers call
"null-merge"::
- $ git merge -s ours v1 # null-merge v1 into v2
+ $ git merge -s ours v1 # null-merge v1 into v2
ReReRe
====================
TODO: dangling objects, git gc, git repack.
+https://gcc.gnu.org/ml/gcc/2007-12/msg00165.html
Tips and tricks
TODO: sticky options; example: git grep -O.
+TODO: tricky options; example: git log -p3.
+
TODO: bash/zsh completion, bash/zsh prompt.
+https://git.kernel.org/cgit/git/git.git/tree/contrib/completion
git on server
TODO: anonymous access; git over ssh; gitolite; gitweb; cgit; gitlab.
+http://gitolite.com/gitolite/index.html
+
+https://git.kernel.org/cgit/git/git.git/tree/gitweb
+
+http://git.zx2c4.com/cgit/
From Mercurial to git
=====================
projects / git-wiki.git / blobdiff