Add draft section ReReRe

[git-wiki.git] / pep-git.txt

diff --git a/pep-git.txt b/pep-git.txt
index 0a120b479eb391b1063c1ae7fea15b77be7d76ea..ca2bc0c6cea147cd0196f1cd8ce56b5deec2e692 100644 (file)
--- a/pep-git.txt
+++ b/pep-git.txt
@@ -14,7 +14,7 @@ Abstract
 
 This Informational PEP collects information about git. There is, of
 course, a lot of documentation for git, so the PEP concentrates on
-more complex issues, topics and scenarios.
+more complex issues, scenarios and topics.
 
 The plan is to extend the PEP in the future collecting information
 about equivalence of Mercurial and git scenarios to help migrating
@@ -86,13 +86,13 @@ Initial configuration
 ---------------------
 
 This simple code is often appears in documentation, but it is
-important so let repeat it here::
+important so let repeat it here. Git marks every commit with author
+and commiter names/emails, so configure your real name and preferred
+email::
 
     $ git config --global user.name "User Name"
     $ git config --global user.email user.name@example.org
 
-Put your real name and preferred email.
-
 
 Examples in this PEP
 ====================
@@ -114,32 +114,34 @@ 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 chain of
-commits (possible with merges). And a branch is a label or a pointer
+"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. Chains of commits
-are unnamed and are usually only lengthening. Labels, on the other
-hand, can be created, moved, renamed and deleted freely.
+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 misleading terminology. A remote repository is
-really remote, you access it via network (well, a remote repository
-can be on your local disk, but it's still remote because it's not the
-current repo).
+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 branches, on the other hand, are branches (pointers to commits)
-in your local repository. They are there for git to remember what
+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).
+repos (you can pull from and push to many remotes). Remote branches
+live under ``remotes/REMOTE`` namespaces, e.g. ``remotes/origin/v2``.
 
-To see the status of remote branches::
+To see the status of remote branches run::
 
     $ git branch -rv
 
-To see local and remote branches (and tags) pointing to commits run::
+To see local and remote branches (and tags) pointing to commits::
 
     $ git log --decorate
 
@@ -157,6 +159,54 @@ 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.
 
+Updating local and remote branches
+----------------------------------
+
+There is a major difference between
+
+::
+
+    $ git fetch REMOTE BRANCH
+
+and
+
+::
+
+    $ git fetch REMOTE BRANCH:BRANCH
+
+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 label).
+
+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.
+
+The first command is used internall by ``git pull``.
+
+::
+
+    $ git pull REMOTE BRANCH
+
+is equivalent to
+
+::
+
+    $ git fetch REMOTE BRANCH
+    $ 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 merge v1
+
 
 Commit editing and caveats
 ==========================
@@ -244,6 +294,10 @@ Git has a builtin strategy for what Python core developers call
     $ git merge -s ours v1 # null-merge v1 into v2
 
 
+ReReRe
+======
+
+
 Database maintenance
 ====================