Merge branch 'master' into teeberg-master

Need latest master to proceed with test
Conflicts:
	doc/source/tutorial.rst

1 files changed, 194 insertions, 263 deletions

diff --git a/doc/source/tutorial.rst b/doc/source/tutorial.rst
index 33a0a884..7f57ec94 100644
--- a/doc/source/tutorial.rst
+++ b/doc/source/tutorial.rst
@@ -8,7 +8,9 @@
 GitPython Tutorial
 ==================
 
-GitPython provides object model access to your git repository. This tutorial is composed of multiple sections, each of which explains a real-life usecase.
+GitPython provides object model access to your git repository. This tutorial is composed of multiple sections, most of which explains a real-life usecase.
+
+All code presented here originated from `test_docs.py <https://github.com/gitpython-developers/GitPython/blob/master/git/test/test_docs.py>`_ to assure correctness. Knowing this should also allow you to more easily run the code for your own testing purposes, all you need is a developer installation of git-python.
 
 Meet the Repo type
 ******************
@@ -17,7 +19,7 @@ The first step is to create a :class:`git.Repo <git.repo.base.Repo>` object to r
 
 .. literalinclude:: ../../git/test/test_docs.py
     :language: python
-    :start-after: def test_init_repo_object
+    :start-after: # [1-test_init_repo_object]
     :end-before: # ![1-test_init_repo_object]
 
 In the above example, the directory ``self.rorepo.working_tree_dir`` equals ``/Users/mtrier/Development/git-python`` and is my working repository which contains the ``.git`` directory. You can also initialize GitPython with a *bare* repository.
@@ -58,7 +60,7 @@ Archive the repository contents to a tar file.
 Advanced Repo Usage
 ===================
 
-And of course, there is much more you can do with this type, most of the following will be explained in greater detail in specific tutorials.
+And of course, there is much more you can do with this type, most of the following will be explained in greater detail in specific tutorials. Don't worry if you don't understand some of these examples right away, as they may require a thorough understanding of gits inner workings.
 
 Query relevant repository paths ... 
 
@@ -120,359 +122,287 @@ The :class:`index <git.index.base.IndexFile>` is also called stage in git-speak.
 Examining References
 ********************
 
-References are the tips of your commit graph from which you can easily examine  the history of your project::
+:class:`References <git.refs.reference.Reference>` are the tips of your commit graph from which you can easily examine the history of your project.
 
-    heads = repo.heads
-    master = heads.master       # lists can be accessed by name for convenience
-    master.commit               # the commit pointed to by head called master
-    master.rename("new_name")   # rename heads
+.. literalinclude:: ../../git/test/test_docs.py
+    :language: python
+    :start-after: # [1-test_references_and_objects]
+    :end-before: # ![1-test_references_and_objects]
     
-Tags are (usually immutable) references to a commit and/or a tag object::
-
-    tags = repo.tags
-    tagref = tags[0]
-    tagref.tag                  # tags may have tag objects carrying additional information
-    tagref.commit               # but they always point to commits
-    repo.delete_tag(tagref)     # delete or
-    repo.create_tag("my_tag")   # create tags using the repo for convenience
+:class:`Tags <git.refs.tag.TagReference>` are (usually immutable) references to a commit and/or a tag object.
+
+.. literalinclude:: ../../git/test/test_docs.py
+    :language: python
+    :start-after: # [2-test_references_and_objects]
+    :end-before: # ![2-test_references_and_objects]
     
-A symbolic reference is a special case of a reference as it points to another reference instead of a commit::
+A :class:`symbolic reference <git.refs.symbolic.SymbolicReference>` is a special case of a reference as it points to another reference instead of a commit.
 
-    head = repo.head            # the head points to the active branch/ref
-    master = head.reference     # retrieve the reference the head points to
-    master.commit               # from here you use it as any other reference
+.. literalinclude:: ../../git/test/test_docs.py
+    :language: python
+    :start-after: # [3-test_references_and_objects]
+    :end-before: # ![3-test_references_and_objects]
     
-Access the reflog easily::
+Access the :class:`reflog <git.refs.log.RefLog>` easily.
     
-    log = master.log()
-    log[0]                      # first (i.e. oldest) reflog entry
-    log[-1]                     # last (i.e. most recent) reflog entry
+.. literalinclude:: ../../git/test/test_docs.py
+    :language: python
+    :start-after: # [4-test_references_and_objects]
+    :end-before: # ![4-test_references_and_objects]
     
-For more information on the reflog, see the :class:`git.RefLog <git.refs.log.RefLog>` type's documentation.
-
 Modifying References
 ********************
-You can easily create and delete reference types or modify where they point to::
+You can easily create and delete :class:`reference types <git.refs.reference.Reference>` or modify where they point to.
 
-    repo.delete_head('master')           # delete an existing head
-    master = repo.create_head('master')  # create a new one
-    master.commit = 'HEAD~10'            # set branch to another commit without changing index or working tree 
+.. literalinclude:: ../../git/test/test_docs.py
+    :language: python
+    :start-after: # [5-test_references_and_objects]
+    :end-before: # ![5-test_references_and_objects]
 
-Create or delete tags the same way except you may not change them afterwards::
+Create or delete :class:`tags <git.refs.tag.TagReference>` the same way except you may not change them afterwards.
 
-    new_tag = repo.create_tag('my_tag', 'my message')
-    repo.delete_tag(new_tag)
+.. literalinclude:: ../../git/test/test_docs.py
+    :language: python
+    :start-after: # [6-test_references_and_objects]
+    :end-before: # ![6-test_references_and_objects]
     
-Change the symbolic reference to switch branches cheaply ( without adjusting the index or the working copy )::
+Change the :class:`symbolic reference <git.refs.symbolic.SymbolicReference>` to switch branches cheaply (without adjusting the index or the working tree).
 
-    new_branch = repo.create_head('new_branch')
-    repo.head.reference = new_branch
+.. literalinclude:: ../../git/test/test_docs.py
+    :language: python
+    :start-after: # [7-test_references_and_objects]
+    :end-before: # ![7-test_references_and_objects]
 
 Understanding Objects
 *********************
-An Object is anything storable in git's object database. Objects contain information about their type, their uncompressed size as well as the actual data. Each object is uniquely identified by a binary SHA1 hash, being 20 bytes in size.
+An Object is anything storable in git's object database. Objects contain information about their type, their uncompressed size as well as the actual data. Each object is uniquely identified by a binary SHA1 hash, being 20 bytes in size, or 40 bytes in hexadecimal notation.
 
-Git only knows 4 distinct object types being Blobs, Trees, Commits and Tags.
+Git only knows 4 distinct object types being :class:`Blobs <git.objects.blob.Blob>`, :class:`Trees <git.objects.tree.Tree>`, :class:`Commits <git.objects.commit.Commit>` and :class:`Tags <git.objects.tag.TagObject>`.
 
-In Git-Python, all objects can be accessed through their common base, compared  and hashed. They are usually not instantiated directly, but through references or specialized repository functions::
+In GitPython, all objects can be accessed through their common base, can be compared and hashed. They are usually not instantiated directly, but through references or specialized repository functions.
 
-    hc = repo.head.commit
-    hct = hc.tree
-    hc != hct
-    hc != repo.tags[0]
-    hc == repo.head.reference.commit
+.. literalinclude:: ../../git/test/test_docs.py
+    :language: python
+    :start-after: # [8-test_references_and_objects]
+    :end-before: # ![8-test_references_and_objects]
     
-Common fields are::
-
-    hct.type
-    'tree'
-    hct.size
-    166
-    hct.hexsha
-    'a95eeb2a7082212c197cabbf2539185ec74ed0e8'
-    hct.binsha
-    'binary 20 byte sha1'
+Common fields are ... 
+
+.. literalinclude:: ../../git/test/test_docs.py
+    :language: python
+    :start-after: # [9-test_references_and_objects]
+    :end-before: # ![9-test_references_and_objects]
     
-Index Objects are objects that can be put into git's index. These objects are trees, blobs and submodules which additionally know about their path in the filesystem as well as their mode::
+:class:`Index objects <git.objects.base.IndexObject>` are objects that can be put into git's index. These objects are trees, blobs and submodules which additionally know about their path in the file system as well as their mode.
     
-    hct.path            # root tree has no path
-    ''
-    hct.trees[0].path   # the first subdirectory has one though
-    'dir'
-    htc.mode            # trees have the mode of a linux directory
-    040000
-    '%o' % htc.blobs[0].mode    # blobs have a specific mode though comparable to a standard linux fs
-    100644
+.. literalinclude:: ../../git/test/test_docs.py
+    :language: python
+    :start-after: # [10-test_references_and_objects]
+    :end-before: # ![10-test_references_and_objects]
     
-Access blob data (or any object data) directly or using streams::
+Access :class:`blob <git.objects.blob.Blob>` data (or any object data) using streams.
     
-    htc.blobs[0].data_stream.read()      # stream object to read data from
-    htc.blobs[0].stream_data(open("blob_data", "w")) # write data to given stream
+.. literalinclude:: ../../git/test/test_docs.py
+    :language: python
+    :start-after: # [11-test_references_and_objects]
+    :end-before: # ![11-test_references_and_objects]
     
     
 The Commit object
 *****************
 
-Commit objects contain information about a specific commit. Obtain commits using  references as done in `Examining References`_ or as follows.
-
-Obtain commits at the specified revision::
-
-    repo.commit('master')
-    repo.commit('v0.1')
-    repo.commit('HEAD~10')
-
-Iterate 100 commits::
-
-    repo.iter_commits('master', max_count=100)
+:class:`Commit <git.objects.commit.Commit>` objects contain information about a specific commit. Obtain commits using  references as done in `Examining References`_ or as follows.
 
-If you need paging, you can specify a number of commits to skip::
+Obtain commits at the specified revision
 
-    repo.iter_commits('master', max_count=10, skip=20)
-
-The above will return commits 21-30 from the commit list.::
-
-    headcommit = repo.head.commit 
+.. literalinclude:: ../../git/test/test_docs.py
+    :language: python
+    :start-after: # [12-test_references_and_objects]
+    :end-before: # ![12-test_references_and_objects]    
 
-    headcommit.hexsha
-    '207c0c4418115df0d30820ab1a9acd2ea4bf4431'
+Iterate 50 commits, and if you need paging, you can specify a number of commits to skip.
 
-    headcommit.parents
-    (<git.Commit "a91c45eee0b41bf3cdaad3418ca3850664c4a4b4">,)
+.. literalinclude:: ../../git/test/test_docs.py
+    :language: python
+    :start-after: # [13-test_references_and_objects]
+    :end-before: # ![13-test_references_and_objects]    
 
-    headcommit.tree
-    <git.Tree "563413aedbeda425d8d9dcbb744247d0c3e8a0ac">
+A commit object carries all sorts of meta-data
 
-    headcommit.author
-    <git.Actor "Michael Trier <mtrier@gmail.com>">
+.. literalinclude:: ../../git/test/test_docs.py
+    :language: python
+    :start-after: # [14-test_references_and_objects]
+    :end-before: # ![14-test_references_and_objects]    
 
-    headcommit.authored_date        # seconds since epoch
-    1256291446
+Note: date time is represented in a ``seconds since epoch`` format. Conversion to human readable form can be accomplished with the various `time module <http://docs.python.org/library/time.html>`_ methods.
 
-    headcommit.committer
-    <git.Actor "Michael Trier <mtrier@gmail.com>">
+.. literalinclude:: ../../git/test/test_docs.py
+    :language: python
+    :start-after: # [15-test_references_and_objects]
+    :end-before: # ![15-test_references_and_objects]    
 
-    headcommit.committed_date
-    1256291446
+You can traverse a commit's ancestry by chaining calls to ``parents``
 
-    headcommit.message
-    'cleaned up a lot of test information. Fixed escaping so it works with
-    subprocess.'
+.. literalinclude:: ../../git/test/test_docs.py
+    :language: python
+    :start-after: # [16-test_references_and_objects]
+    :end-before: # ![16-test_references_and_objects]        
 
-Note: date time is represented in a ``seconds since epoch`` format. Conversion to human readable form can be accomplished with the various `time module <http://docs.python.org/library/time.html>`_ methods::
+The above corresponds to ``master^^^`` or ``master~3`` in git parlance.
 
-    import time
-    time.asctime(time.gmtime(headcommit.committed_date))
-    'Wed May 7 05:56:02 2008'
+The Tree object
+***************
 
-    time.strftime("%a, %d %b %Y %H:%M", time.gmtime(headcommit.committed_date))
-    'Wed, 7 May 2008 05:56'
+A :class:`tree <git.objects.tree.Tree>` records pointers to the contents of a directory. Let's say you want the root tree of the latest commit on the master branch
 
-You can traverse a commit's ancestry by chaining calls to ``parents``::
+.. literalinclude:: ../../git/test/test_docs.py
+    :language: python
+    :start-after: # [17-test_references_and_objects]
+    :end-before: # ![17-test_references_and_objects]            
 
-    headcommit.parents[0].parents[0].parents[0]
+Once you have a tree, you can get it's contents
 
-The above corresponds to ``master^^^`` or ``master~3`` in git parlance.
+.. literalinclude:: ../../git/test/test_docs.py
+    :language: python
+    :start-after: # [18-test_references_and_objects]
+    :end-before: # ![18-test_references_and_objects]            
 
-The Tree object
-***************
+It is useful to know that a tree behaves like a list with the ability to query entries by name
 
-A tree records pointers to the contents of a directory. Let's say you want the root tree of the latest commit on the master branch::
+.. literalinclude:: ../../git/test/test_docs.py
+    :language: python
+    :start-after: # [19-test_references_and_objects]
+    :end-before: # ![19-test_references_and_objects]            
 
-    tree = repo.heads.master.commit.tree
-    <git.Tree "a006b5b1a8115185a228b7514cdcd46fed90dc92">
+There is a convenience method that allows you to get a named sub-object from a tree with a syntax similar to how paths are written in a posix system
 
-    tree.hexsha
-    'a006b5b1a8115185a228b7514cdcd46fed90dc92'
+.. literalinclude:: ../../git/test/test_docs.py
+    :language: python
+    :start-after: # [20-test_references_and_objects]
+    :end-before: # ![20-test_references_and_objects]                
 
-Once you have a tree, you can get the contents::
+You can also get a commit's root tree directly from the repository
 
-    tree.trees          # trees are subdirectories
-    [<git.Tree "f7eb5df2e465ab621b1db3f5714850d6732cfed2">]
-    
-    tree.blobs          # blobs are files
-    [<git.Blob "a871e79d59cf8488cac4af0c8f990b7a989e2b53">,
-    <git.Blob "3594e94c04db171e2767224db355f514b13715c5">,
-    <git.Blob "e79b05161e4836e5fbf197aeb52515753e8d6ab6">,
-    <git.Blob "94954abda49de8615a048f8d2e64b5de848e27a1">]
-
-Its useful to know that a tree behaves like a list with the ability to  query entries by name::
-
-    tree[0] == tree['dir']			# access by index and by sub-path
-    <git.Tree "f7eb5df2e465ab621b1db3f5714850d6732cfed2">
-    for entry in tree: do_something_with(entry)
-
-    blob = tree[0][0]
-    blob.name
-    'file'
-    blob.path
-    'dir/file'
-    blob.abspath
-    '/Users/mtrier/Development/git-python/dir/file'
-    >>>tree['dir/file'].binsha == blob.binsha
-
-There is a convenience method that allows you to get a named sub-object from a tree with a syntax similar to how paths are written in an unix system::
-
-    tree/"lib"
-    <git.Tree "c1c7214dde86f76bc3e18806ac1f47c38b2b7a30">
-    tree/"dir/file" == blob
-
-You can also get a tree directly from the repository if you know its name::
-
-    repo.tree()
-    <git.Tree "master">
-
-    repo.tree("c1c7214dde86f76bc3e18806ac1f47c38b2b7a30")
-    <git.Tree "c1c7214dde86f76bc3e18806ac1f47c38b2b7a30">
-    repo.tree('0.1.6')
-    <git.Tree "6825a94104164d9f0f5632607bebd2a32a3579e5">
+.. literalinclude:: ../../git/test/test_docs.py
+    :language: python
+    :start-after: # [21-test_references_and_objects]
+    :end-before: # ![21-test_references_and_objects]    
     
-As trees only allow direct access to their direct entries, use the traverse  method to obtain an iterator to traverse entries recursively::
+As trees allow direct access to their intermediate child entries only, use the traverse method to obtain an iterator to retrieve entries recursively
 
-    tree.traverse()
-    <generator object at 0x7f6598bd65a8>
-    for entry in tree.traverse(): do_something_with(entry)
-    
+.. literalinclude:: ../../git/test/test_docs.py
+    :language: python
+    :start-after: # [22-test_references_and_objects]
+    :end-before: # ![22-test_references_and_objects]        
     
-.. note:: If tree's return Submodule objects, they will assume that they exist at the current head's commit. The tree it originated from may be rooted at another commit though, which has to be told to the Submodule object using its ``set_parent_commit(my_commit)`` method.
-
+.. note:: If trees return Submodule objects, they will assume that they exist at the current head's commit. The tree it originated from may be rooted at another commit though, that it doesn't know. That is why the caller would have to set the submodule's owning or parent commit using the ``set_parent_commit(my_commit)`` method.
     
 The Index Object
 ****************
-The git index is the stage containing changes to be written with the next commit or where merges finally have to take place. You may freely access and manipulate  this information using the IndexFile Object::
-
-    index = repo.index
+The git index is the stage containing changes to be written with the next commit or where merges finally have to take place. You may freely access and manipulate this information using the :class:`IndexFile <git.index.base.IndexFile>` object.
+Modify the index with ease
     
-Access objects and add/remove entries. Commit the changes::
-
-    for stage, blob in index.iter_blobs(): do_something(...)
-    # Access blob objects
-    for (path, stage), entry in index.entries.iteritems: pass
-    # Access the entries directly
-    index.add(['my_new_file'])      # add a new file to the index
-    index.remove(['dir/existing_file'])
-    new_commit = index.commit("my commit message") # commit by commit message first
-    my_author = Actor("An author", "author@example.com")
-    my_committer = Actor("A committer", "committer@example.com")
-    next_commit = index.commit("my commit message", author=my_author, commiter=my_committer) # commit by commit message and author and committer
+.. literalinclude:: ../../git/test/test_docs.py
+    :language: python
+    :start-after: # [23-test_references_and_objects]
+    :end-before: # ![23-test_references_and_objects]        
     
-Create new indices from other trees or as result of a merge. Write that result to a new index file::
+Create new indices from other trees or as result of a merge. Write that result to a new index file for later inspection.
 
-    tmp_index = Index.from_tree(repo, 'HEAD~1') # load a tree into a temporary index
-    merge_index = Index.from_tree(repo, 'base', 'HEAD', 'some_branch') # merge two trees three-way
-    merge_index.write("merged_index")
+.. literalinclude:: ../../git/test/test_docs.py
+    :language: python
+    :start-after: # [24-test_references_and_objects]
+    :end-before: # ![24-test_references_and_objects]        
     
 Handling Remotes
 ****************
 
-Remotes are used as alias for a foreign repository to ease pushing to and fetching from them::
+:class:`Remotes <git.remote.Remote>` are used as alias for a foreign repository to ease pushing to and fetching from them
 
-    test_remote = repo.create_remote('test', 'git@server:repo.git')
-    repo.delete_remote(test_remote) # create and delete remotes
-    origin = repo.remotes.origin    # get default remote by name
-    origin.refs                     # local remote references
-    o = origin.rename('new_origin') # rename remotes
-    o.fetch()                       # fetch, pull and push from and to the remote
-    o.pull()
-    o.push()
+.. literalinclude:: ../../git/test/test_docs.py
+    :language: python
+    :start-after: # [25-test_references_and_objects]
+    :end-before: # ![25-test_references_and_objects]            
 
-You can easily access configuration information for a remote by accessing options  as if they where attributes::
+You can easily access configuration information for a remote by accessing options as if they where attributes. The modification of remote configuration is more explicit though.
     
-    o.url
-    'git@server:dummy_repo.git'
-    
-Change configuration for a specific remote only::
-    
-    o.config_writer.set("pushurl", "other_url")
+.. literalinclude:: ../../git/test/test_docs.py
+    :language: python
+    :start-after: # [26-test_references_and_objects]
+    :end-before: # ![26-test_references_and_objects]
 
-You can also specify an SSH key to use for any operations on the remotes::
+You can also specify an SSH key to use for any operations on the remotes
 
-    private_key_file = project_dir+'id_rsa_deployment_key'
-    with repo.git.sshkey(private_key_file):
-        o.fetch()
-    
+.. literalinclude:: ../../git/test/test_docs.py
+    :language: python
+    :start-after: # [32-test_references_and_objects]
+    :end-before: # ![32-test_references_and_objects]    
     
 Submodule Handling
 ******************
-Submodules can be conveniently handled using the methods provided by Git-Python, and as an added benefit, Git-Python provides functionality which behave smarter and less error prone than its original c-git implementation, that is Git-Python tries hard to keep your repository consistent when updating submodules recursively or adjusting the existing configuration.
+:class:`Submodules <git.objects.submodule.base.Submodule>` can be conveniently handled using the methods provided by GitPython, and as an added benefit, GitPython provides functionality which behave smarter and less error prone than its original c-git implementation, that is GitPython tries hard to keep your repository consistent when updating submodules recursively or adjusting the existing configuration.
 
-In the following brief example, you will learn about the very basics, assuming you operate on the Git-Python repository itself::
-    
-    >>> repo = Repo('path/to/git-python/repository')
-    >>> sms = repo.submodules
-    [git.Submodule(name=gitdb, path=lib/git/ext/gitdb, url=git://github.com/gitpython-developers/GitPython.git, branch=master)]
-    >>> sm = sms[0]
-    >>> sm.name
-    'gitdb'
-    >>> sm.module()                                        # The module is the actual repository referenced by the submodule 
-    <git.Repo "<prefix>/git-python/lib/git/ext/gitdb/.git">
-    >>> sm.module_exists()
-    True
-    >>> sm.abspath == sm.module().working_tree_dir         # the submodule's absolute path is the module's path
-    True
-    >>> sm.hexsha                                          # Its sha defines the commit to checkout
-    '2ddc5bad224d8f545ef3bb2ab3df98dfe063c5b6'
-    >>> sm.exists()                                        # yes, this submodule is valid and exists
-    True
-    >>> sm.config_reader().get_value('path') == sm.path    # read its configuration conveniently
-    True
-    >>> sm.children()                                      # query the submodule hierarchy
-    [git.Submodule(name=async, path=ext/async, url=git://github.com/gitpython-developers/async.git, branch=master)]
-
-In addition to the query functionality, you can move the submodule's repository to a different path <``move(...)``>, write its configuration <``config_writer().set_value(...)``>, update its working tree <``update(...)``>, and remove and add them <``remove(...)``, ``add(...)``>.
+.. literalinclude:: ../../git/test/test_docs.py
+    :language: python
+    :start-after: # [1-test_submodules]
+    :end-before: # ![1-test_submodules]                
+
+In addition to the query functionality, you can move the submodule's repository to a different path <``move(...)``>, write its configuration <``config_writer().set_value(...).release()``>, update its working tree <``update(...)``>, and remove or add them <``remove(...)``, ``add(...)``>.
 
 If you obtained your submodule object by traversing a tree object which is not rooted at the head's commit, you have to inform the submodule about its actual commit to retrieve the data from by using the ``set_parent_commit(...)`` method.
 
-The special ``RootModule`` type allows you to treat your master repository as root of a hierarchy of submodules, which allows very convenient submodule handling. Its ``update(...)`` method is reimplemented to provide an advanced way of updating submodules as they change their values. The update method will track changes and make sure your working tree and submodule checkouts stay consistent, which is very useful in case submodules get deleted or added to name just two of the handled cases.
+The special :class:`RootModule <git.objects.submodule.root.RootModule>` type allows you to treat your master repository as root of a hierarchy of submodules, which allows very convenient submodule handling. Its ``update(...)`` method is reimplemented to provide an advanced way of updating submodules as they change their values over time. The update method will track changes and make sure your working tree and submodule checkouts stay consistent, which is very useful in case submodules get deleted or added to name just two of the handled cases.
 
-Additionally, Git-Python adds functionality to track a specific branch, instead of just a commit. Supported by customized update methods, you are able to automatically update submodules to the latest revision available in the remote repository, as well as to keep track of changes and movements of these submodules. To use it, set the name of the branch you want to track to the ``submodule.$name.branch`` option of the *.gitmodules*  file, and use Git-Python update methods on the resulting repository with the ``to_latest_revision`` parameter turned on. In the latter case, the sha of your submodule will be ignored, instead a local tracking branch will be updated to the respective remote branch automatically. The resulting behaviour is much like the one of svn::externals, which can be useful in times. 
+Additionally, GitPython adds functionality to track a specific branch, instead of just a commit. Supported by customized update methods, you are able to automatically update submodules to the latest revision available in the remote repository, as well as to keep track of changes and movements of these submodules. To use it, set the name of the branch you want to track to the ``submodule.$name.branch`` option of the *.gitmodules*  file, and use GitPython update methods on the resulting repository with the ``to_latest_revision`` parameter turned on. In the latter case, the sha of your submodule will be ignored, instead a local tracking branch will be updated to the respective remote branch automatically, provided there are no local changes. The resulting behaviour is much like the one of svn::externals, which can be useful in times. 
 
 Obtaining Diff Information
 **************************
 
-Diffs can generally be obtained by subclasses of ``Diffable`` as they provide  the ``diff`` method. This operation yields a DiffIndex allowing you to easily access diff information about paths.
+Diffs can generally be obtained by subclasses of :class:`Diffable <git.diff.Diffable>` as they provide the ``diff`` method. This operation yields a :class:`DiffIndex <git.diff.DiffIndex>` allowing you to easily access diff information about paths.
 
-Diffs can be made between the Index and Trees, Index and the working tree, trees and trees as well as trees and the working copy. If commits are involved, their tree will be used implicitly::
+Diffs can be made between the Index and Trees, Index and the working tree, trees and trees as well as trees and the working copy. If commits are involved, their tree will be used implicitly.
 
-    hcommit = repo.head.commit
-    idiff = hcommit.diff()          # diff tree against index
-    tdiff = hcommit.diff('HEAD~1')  # diff tree against previous tree
-    wdiff = hcommit.diff(None)      # diff tree against working tree
-    
-    index = repo.index
-    index.diff()                    # diff index against itself yielding empty diff
-    index.diff(None)                # diff index against working copy
-    index.diff('HEAD')              # diff index against current HEAD tree
+.. literalinclude:: ../../git/test/test_docs.py
+    :language: python
+    :start-after: # [27-test_references_and_objects]
+    :end-before: # ![27-test_references_and_objects]                
 
-The item returned is a DiffIndex which is essentially a list of Diff objects. It  provides additional filtering to ease finding what you might be looking for::
+The item returned is a DiffIndex which is essentially a list of Diff objects. It provides additional filtering to ease finding what you might be looking for.
 
-    for diff_added in wdiff.iter_change_type('A'): do_something_with(diff_added)
+.. literalinclude:: ../../git/test/test_docs.py
+    :language: python
+    :start-after: # [28-test_references_and_objects]
+    :end-before: # ![28-test_references_and_objects]
 
-Use the diff framework if you want to implement git-status like functionality.     
+Use the diff framework if you want to implement git-status like functionality.
 
 * A diff between the index and the commit's tree your HEAD points to
  
- * use repo.index.diff(repo.head)
+ * use ``repo.index.diff(repo.head)``
   
 * A diff between the index and the working tree
  
- * use repo.index.diff(None)
+ * use ``repo.index.diff(None)``
   
 * A list of untracked files
  
- * use repo.untracked_files
+ * use ``repo.untracked_files``
 
-    
 Switching Branches
 ******************
-To switch between branches, you effectively need to point your HEAD to the new branch head and reset your index and working copy to match. A simple manual way to do it is the following one::
+To switch between branches similar to ``git checkout``, you effectively need to point your HEAD symbolic reference to the new branch and reset your index and working copy to match. A simple manual way to do it is the following one
 
-    repo.head.reference = repo.heads.other_branch
-    repo.head.reset(index=True, working_tree=True)
+.. literalinclude:: ../../git/test/test_docs.py
+    :language: python
+    :start-after: # [29-test_references_and_objects]
+    :end-before: # ![29-test_references_and_objects]
     
-The previous approach would brutally overwrite the user's changes in the working copy and index though and is less sophisticated than a git-checkout for instance which generally prevents you from destroying your work. Use the safer approach as follows::
+The previous approach would brutally overwrite the user's changes in the working copy and index though and is less sophisticated than a ``git-checkout``. The latter will generally prevent you from destroying your work. Use the safer approach as follows.
 
-	repo.heads.master.checkout()			# checkout the branch using git-checkout
-	repo.heads.other_branch.checkout()
+.. literalinclude:: ../../git/test/test_docs.py
+    :language: python
+    :start-after: # [30-test_references_and_objects]
+    :end-before: # ![30-test_references_and_objects]
 
 Initializing a repository
 *************************
@@ -488,18 +418,19 @@ Please have a look at the individual methods as they usually support a vast amou
 
 Using git directly
 ******************
-In case you are missing functionality as it has not been wrapped, you may conveniently use the git command directly. It is owned by each repository instance::
+In case you are missing functionality as it has not been wrapped, you may conveniently use the :class:`git <git.cmd.Git>` command directly. It is owned by each repository instance.
 
-    git = repo.git
-    git.checkout('head', b="my_new_branch")         # default command
-    git.for_each_ref()                              # '-' becomes '_' when calling it
+.. literalinclude:: ../../git/test/test_docs.py
+    :language: python
+    :start-after: # [31-test_references_and_objects]
+    :end-before: # ![31-test_references_and_objects]
     
 The return value will by default be a string of the standard output channel produced by the command.
 
-Keyword arguments translate to short and long keyword arguments on the commandline.
+Keyword arguments translate to short and long keyword arguments on the command-line.
 The special notion ``git.command(flag=True)`` will create a flag without value like ``command --flag``.
 
-If ``None`` is found in the arguments, it will be dropped silently. Lists and tuples  passed as arguments will be unpacked recursively to individual arguments. Objects are converted to strings using the str(...) function.
+If ``None`` is found in the arguments, it will be dropped silently. Lists and tuples passed as arguments will be unpacked recursively to individual arguments. Objects are converted to strings using the ``str(...)`` function.
 
 
 Object Databases
@@ -528,8 +459,8 @@ Using environment variables, you can further adjust the behaviour of the git com
 
 * **GIT_PYTHON_TRACE**
 
- * If set to non-0, all executed git commands will be printed to stdout.
- * if set to *full*, the executed git command will be printed along with its output.
+ * If set to non-0, all executed git commands will be logged using a python logger.
+ * if set to *full*, the executed git command and its output on stdout and stderr will be logged using a python logger.
  
 * **GIT_PYTHON_GIT_EXECUTABLE**
 
@@ -538,7 +469,7 @@ Using environment variables, you can further adjust the behaviour of the git com
 And even more ...
 *****************
 
-There is more functionality in there, like the ability to archive repositories, get stats and logs, blame, and probably a few other things that were not mentioned here.  
+There is more functionality in there, like the ability to archive repositories, get stats and logs, blame, and probably a few other things that were not mentioned here.
 
 Check the unit tests for an in-depth introduction on how each function is supposed to be used.