X-Git-Url: https://git.phdru.name/?a=blobdiff_plain;f=pep-git.txt;h=fcdfc633980e8d538bcdc2cf21273e8782ae17fa;hb=6236c4807648a130f54fb2f01fc458e80b274d47;hp=c8212e94fbfe41b975e868067a63a6567d83ca47;hpb=be5d53989b02ecb3f74fa33c55657a5c050a2355;p=git-wiki.git diff --git a/pep-git.txt b/pep-git.txt index c8212e9..fcdfc63 100644 --- a/pep-git.txt +++ b/pep-git.txt @@ -3,7 +3,7 @@ Title: Collecting information about git Version: $Revision$ Last-Modified: $Date$ Author: Oleg Broytman -Status: Active +Status: Draft Type: Informational Content-Type: text/x-rst Created: 01-Jun-2015 @@ -45,13 +45,13 @@ Git Tutorial: `part 1 `Git workflows `_. +Advanced documentation +---------------------- + `Git Magic `_, also with a number of translations. -Advanced documentation ----------------------- - `Pro Git `_. 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 @@ -79,17 +79,25 @@ Microsoft Windows: download `git-for-windows `_. MacOS X: use git installed with `XCode -`_ or download +`_ or download from +`MacPorts `_ or `git-osx-installer -`_. +`_ or +install git with `Homebrew `_: ``brew install git``. + +`git-cola `_ is a Git GUI +written in Python and GPL licensed. Linux, Windows, MacOS X. + +`TortoiseGit `_ 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 @@ -109,18 +117,23 @@ done something like that:: $ 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-tracking 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. +remotes/origin/v1 as its upstream remote-tracking 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 $ git checkout --track origin/v2 -The last command 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 v2, sets remotes/origin/v2 +as its upstream remote-tracking branch and checks it out into the +working directory. Branches and branches @@ -129,51 +142,49 @@ Branches and branches Git terminology can be a bit misleading. Take, for example, the term "branch". In git it has two meanings. A branch is a directed line of commits (possibly with merges). And a branch is a label or a pointer -assigned to a line of commits. It is important to differentiate when -you talk about commits and when about their labels. Lines of commits -are by itself unnamed and are usually only lengthening and merging. +assigned to a line of commits. It is important to distinguish when you +talk about commits and when about their labels. Lines of commits are +by itself unnamed and are usually only lengthening and merging. Labels, on the other hand, can be created, moved, renamed and deleted freely. -Remote repository and remote branches -===================================== - -Another example of slightly misleading terminology. Remote -repositories are really remote, you access them via network (well, a -remote repository can be on your local disk, but it's still remote -because it's not the current repo). +Remote repositories and remote branches +======================================= -Remote branches, on the other hand, are branches (pointers to commits) -in your local repository. They are there for you to remember what -branches and commits have been pulled from and pushed to what remote -repos (you can pull from and push to many remotes). Remote branches -live under ``remotes/REMOTE`` namespaces, e.g. ``remotes/origin/v2``. +Remote-tracking branches are branches (pointers to commits) in your +local repository. They are there for you to remember what branches and +commits have been pulled from and pushed to what remote repos (you can +pull from and push to many remotes). Remote-tracking branches live +under ``remotes/REMOTE`` namespaces, e.g. ``remotes/origin/v2``. -To see the status of remote branches run:: +To see the status of remote-tracking branches run:: $ git branch -rv -To see local and remote branches (and tags) pointing to commits:: +To see local and remote-tracking branches (and tags) pointing to +commits:: $ git log --decorate -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. +You never do your own development on remote-tracking branches. You +create a local branch that has a remote branch as upstream and do +development on that local branch. On push git pushes commits to the +remote repo and updates remote-tracking branches, on pull git fetches +commits from the remote repo, updates remote-tracking branches and +fast-forwards, merges or rebases local branches. When you do an initial clone like this:: $ git clone -b v1 http://git.python.org/python.git git clones remote repository ``http://git.python.org/python.git`` to -directory ``python``, creates remote branches and checks out branch -``v1`` into the working directory. +directory ``python``, creates remote-tracking branches, creates a +local branch ``v1``, configure it to track upstream remotes/origin/v1 +branch and checks out ``v1`` into the working directory. -Updating local and remote branches ----------------------------------- +Updating local and remote-tracking branches +------------------------------------------- There is a major difference between @@ -189,14 +200,14 @@ and The first command fetches commits from the named BRANCH in the REMOTE repository that are not in your repository and leaves the id (the -hash) of the head commit in file .git/FETCH_HEAD. But it doesn't -update any branch (doesn't move any pointer). +hash) of the head commit in file .git/FETCH_HEAD and +updates remote-tracking branch. The second command fetches commits from the named BRANCH in the REMOTE repository that are not in your repository and updates both the local -branch BRANCH and its upstream remote branch. But it refuses to update -branches in case of non-fast-forward. And it refuses to update the -current branch. +branch BRANCH and its upstream remote-tracking branch. But it refuses +to update branches in case of non-fast-forward. And it refuses to +update the current branch. The first command is used internally by ``git pull``. @@ -209,15 +220,29 @@ is equivalent to :: $ 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 @@ -233,6 +258,10 @@ or even $ git pull +Default remote repository for fetching/pulling is origin. Default set +of references to fetch is calculated using matching algorithm: git +fetches all branches having the same name on both ends. + Push '''' @@ -243,17 +272,16 @@ run $ git push origin v1 v2 -git guesses (knowing upstream remote branches) that you really want - -:: +git pushes local v1 to remote v1 and local v2 to remote v2. The same +as:: $ git push origin v1:v1 v2:v2 -Git pushes commits to the remote repo and updates remote branches. Git -refuses to push commits that aren't fast-forwardable. You can -force-push anyway, but please remember - you can force-push to your -own repositories but don't force-push to public or shared repos. If -you find git refuses to push commits that aren't fast-forwardable, +Git pushes commits to the remote repo and updates remote-tracking +branches. Git refuses to push commits that aren't fast-forwardable. +You can force-push anyway, but please remember - you can force-push to +your own repositories but don't force-push to public or shared repos. +If you find git refuses to push commits that aren't fast-forwardable, better fetch and merge commits from the remote repo (or rebase your commits on top of the fetched commits), then push. Only force-push if you know what you do and why you do it. See the section `Commit @@ -272,11 +300,32 @@ or even $ git push +Default remote repository for pushing is origin. Default set +of references to push in git before 2.0 is calculated using matching +algorithm: git pushes all branches having the same name on both ends. +Default set of references to push in git 2.0+ is calculated using +simple algorithm: git pushes the current branch back to its +@{upstream}. + +To configure git before 2.0 to the new behaviour run:: + +$ git config push.default simple + +To configure git 2.0+ to the old behaviour run:: + +$ git config push.default matching + Git refuses to push a branch if it's the current branch in the remote non-bare repository: git refuses to update remote working directory. You really should push only to bare repositories. For non-bare repositories git prefers pull-based workflow. +When you want to deploy code on a remote host and can only use push +(because your workstation is behind a firewall and you cannot pull +from it) you do that in two steps using two repositories: you push +from the workstation to a bare repo on the remote host, ssh to the +remote host and pull from the bare repo to a non-bare deployment repo. + Tags '''' @@ -285,7 +334,7 @@ during fetch/pull. To fetch all tags (and commits they point to) run ``git fetch --tags origin``. To fetch some specific tags fetch them explicitly:: - $ git fetch origin tag NAME1 tag NAME2... + $ git fetch origin tag TAG1 tag TAG2... For example:: @@ -293,11 +342,14 @@ For example:: Git doesn't automatically pushes tags. That allows you to have private tags (lightweight tags are also private for a repo, they cannot be -pushed). To push tag(s) list them explicitly:: +pushed). To push tags list them explicitly:: $ git push origin tag 1.4.2 $ git push origin v1 v2 tag 2.1.7 +Don't move tags with ``git tag -f`` or remove tags with ``git tag -d`` +after they have been published. + Commit editing and caveats ========================== @@ -309,14 +361,14 @@ It is possible to recover from forced push but it's PITA for the entire team. Please avoid it. To see what commits have not been published yet compare the head of the -branch with its upstream remote branch:: +branch with its upstream remote-tracking branch:: $ git log origin/v2.. $ git log origin/v1..v1 -For every branch that has an upstream remote branch git maintains an -alias @{upstream} (short version @{u}), so the commands above can be -given as:: +For every branch that has an upstream remote-tracking branch git +maintains an alias @{upstream} (short version @{u}), so the commands +above can be given as:: $ git log @{u}.. $ git log v1@{u}..v1 @@ -344,38 +396,109 @@ or shared repository. 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:: -How to undo a merge -https://kernel.org/pub/software/scm/git/docs/howto/revert-a-faulty-merge.html + git checkout HEAD~ README +The commands restores the contents of README file to the last but one +commit in the current branch. By default a commit ID is simply HEAD; +i.e. ``git checkout README`` restores README to the latest commit. -Advanced topics -=============== +(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``). -Staging area ------------- +``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. -Staging area aka index is a distinguishing feature of git. See -`WhatIsTheIndex -`_ and -`IndexCommandQuickref -`_ in Git -Wiki. +``git reset`` has three modes of operation - soft, hard and mixed. +Default is mixed. ProGit `explains +`_ 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 `_ +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://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 @@ -384,6 +507,20 @@ ReReRe https://git-scm.com/book/en/Git-Tools-Rerere +Advanced topics +=============== + +Staging area +------------ + +Staging area aka index is a distinguishing feature of git. See +`WhatIsTheIndex +`_ and +`IndexCommandQuickref +`_ in Git +Wiki. + + Advanced configuration ====================== @@ -400,12 +537,32 @@ Database maintenance TODO: dangling objects, git gc, git repack. +https://gcc.gnu.org/ml/gcc/2007-12/msg00165.html + +http://vcscompare.blogspot.ru/2008/06/git-repack-parameters.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 =====================