Glossary
Ancestor
Any changeset that can be reached by an unbroken chain of parent
changesets from a given changeset. More precisely, the ancestors of a
changeset can be defined by two properties: a parent of a changeset is
an ancestor, and a parent of an ancestor is an ancestor. See also:
'Descendant'.
Bookmark
Bookmarks are pointers to certain commits that move when committing.
They are similar to tags in that it is possible to use bookmark names
in all places where Mercurial expects a changeset ID, e.g., with "hg
update". Unlike tags, bookmarks move along when you make a commit.
Bookmarks can be renamed, copied and deleted. Bookmarks are local,
unless they are explicitly pushed or pulled between repositories.
Pushing and pulling bookmarks allow you to collaborate with others on
a branch without creating a named branch.
Branch
(Noun) A child changeset that has been created from a parent that is
not a head. These are known as topological branches, see 'Branch,
topological'. If a topological branch is named, it becomes a named
branch. If a topological branch is not named, it becomes an anonymous
branch. See 'Branch, anonymous' and 'Branch, named'.
Branches may be created when changes are pulled from or pushed to a
remote repository, since new heads may be created by these operations.
Note that the term branch can also be used informally to describe a
development process in which certain development is done independently
of other development. This is sometimes done explicitly with a named
branch, but it can also be done locally, using bookmarks or clones and
anonymous branches.
Example: "The experimental branch".
(Verb) The action of creating a child changeset which results in its
parent having more than one child.
Example: "I'm going to branch at X".
Branch, anonymous
Every time a new child changeset is created from a parent that is not
a head and the name of the branch is not changed, a new anonymous
branch is created.
Branch, closed
A named branch whose branch heads have all been closed.
Branch, default
The branch assigned to a changeset when no name has previously been
assigned.
Branch head
See 'Head, branch'.
Branch, inactive
If a named branch has no topological heads, it is considered to be
inactive. As an example, a feature branch becomes inactive when it is
merged into the default branch. The "hg branches" command shows
inactive branches by default, though they can be hidden with "hg
branches --active".
NOTE: this concept is deprecated because it is too implicit. Branches
should now be explicitly closed using "hg commit --close-branch" when
they are no longer needed.
Branch, named
A collection of changesets which have the same branch name. By
default, children of a changeset in a named branch belong to the same
named branch. A child can be explicitly assigned to a different
branch. See "hg help branch", "hg help branches" and "hg commit
--close-branch" for more information on managing branches.
Named branches can be thought of as a kind of namespace, dividing the
collection of changesets that comprise the repository into a
collection of disjoint subsets. A named branch is not necessarily a
topological branch. If a new named branch is created from the head of
another named branch, or the default branch, but no further changesets
are added to that previous branch, then that previous branch will be a
branch in name only.
Branch tip
See 'Tip, branch'.
Branch, topological
Every time a new child changeset is created from a parent that is not
a head, a new topological branch is created. If a topological branch
is named, it becomes a named branch. If a topological branch is not
named, it becomes an anonymous branch of the current, possibly
default, branch.
Changelog
A record of the changesets in the order in which they were added to
the repository. This includes details such as changeset id, author,
commit message, date, and list of changed files.
Changeset
A snapshot of the state of the repository used to record a change.
Changeset, child
The converse of parent changeset: if P is a parent of C, then C is a
child of P. There is no limit to the number of children that a
changeset may have.
Changeset id
A SHA-1 hash that uniquely identifies a changeset. It may be
represented as either a "long" 40 hexadecimal digit string, or a
"short" 12 hexadecimal digit string.
Changeset, merge
A changeset with two parents. This occurs when a merge is committed.
Changeset, parent
A revision upon which a child changeset is based. Specifically, a
parent changeset of a changeset C is a changeset whose node
immediately precedes C in the DAG. Changesets have at most two
parents.
Checkout
(Noun) The working directory being updated to a specific revision.
This use should probably be avoided where possible, as changeset is
much more appropriate than checkout in this context.
Example: "I'm using checkout X."
(Verb) Updating the working directory to a specific changeset. See "hg
help update".
Example: "I'm going to check out changeset X."
Child changeset
See 'Changeset, child'.
Close changeset
See 'Head, closed branch'
Closed branch
See 'Branch, closed'.
Clone
(Noun) An entire or partial copy of a repository. The partial clone
must be in the form of a revision and its ancestors.
Example: "Is your clone up to date?".
(Verb) The process of creating a clone, using "hg clone".
Example: "I'm going to clone the repository".
Closed branch head
See 'Head, closed branch'.
Commit
(Noun) A synonym for changeset.
Example: "Is the bug fixed in your recent commit?"
(Verb) The act of recording changes to a repository. When files are
committed in a working directory, Mercurial finds the differences
between the committed files and their parent changeset, creating a new
changeset in the repository.
Example: "You should commit those changes now."
Cset
A common abbreviation of the term changeset.
DAG
The repository of changesets of a distributed version control system
(DVCS) can be described as a directed acyclic graph (DAG), consisting
of nodes and edges, where nodes correspond to changesets and edges
imply a parent -> child relation. This graph can be visualized by
graphical tools such as "hg glog" (graphlog). In Mercurial, the DAG is
limited by the requirement for children to have at most two parents.
Default branch
See 'Branch, default'.
Descendant
Any changeset that can be reached by a chain of child changesets from
a given changeset. More precisely, the descendants of a changeset can
be defined by two properties: the child of a changeset is a
descendant, and the child of a descendant is a descendant. See also:
'Ancestor'.
Diff
(Noun) The difference between the contents and attributes of files in
two changesets or a changeset and the current working directory. The
difference is usually represented in a standard form called a "diff"
or "patch". The "git diff" format is used when the changes include
copies, renames, or changes to file attributes, none of which can be
represented/handled by classic "diff" and "patch".
Example: "Did you see my correction in the diff?"
(Verb) Diffing two changesets is the action of creating a diff or
patch.
Example: "If you diff with changeset X, you will see what I mean."
Directory, working
The working directory represents the state of the files tracked by
Mercurial, that will be recorded in the next commit. The working
directory initially corresponds to the snapshot at an existing
changeset, known as the parent of the working directory. See 'Parent,
working directory'. The state may be modified by changes to the files
introduced manually or by a merge. The repository metadata exists in
the .hg directory inside the working directory.
Draft
Changesets in the draft phase have not been shared with publishing
repositories and may thus be safely changed by history-modifying
extensions. See "hg help phases".
Graph
See DAG and "hg help graphlog".
Head
The term 'head' may be used to refer to both a branch head or a
repository head, depending on the context. See 'Head, branch' and
'Head, repository' for specific definitions.
Heads are where development generally takes place and are the usual
targets for update and merge operations.
Head, branch
A changeset with no descendants on the same named branch.
Head, closed branch
A changeset that marks a head as no longer interesting. The closed
head is no longer listed by "hg heads". A branch is considered closed
when all its heads are closed and consequently is not listed by "hg
branches".
Closed heads can be re-opened by committing new changeset as the child
of the changeset that marks a head as closed.
Head, repository
A topological head which has not been closed.
Head, topological
A changeset with no children in the repository.
History, immutable
Once committed, changesets cannot be altered. Extensions which appear
to change history actually create new changesets that replace existing
ones, and then destroy the old changesets. Doing so in public
repositories can result in old changesets being reintroduced to the
repository.
History, rewriting
The changesets in a repository are immutable. However, extensions to
Mercurial can be used to alter the repository, usually in such a way
as to preserve changeset contents.
Immutable history
See 'History, immutable'.
Merge changeset
See 'Changeset, merge'.
Manifest
Each changeset has a manifest, which is the list of files that are
tracked by the changeset.
Merge
Used to bring together divergent branches of work. When you update to
a changeset and then merge another changeset, you bring the history of
the latter changeset into your working directory. Once conflicts are
resolved (and marked), this merge may be committed as a merge
changeset, bringing two branches together in the DAG.
Named branch
See 'Branch, named'.
Null changeset
The empty changeset. It is the parent state of newly-initialized
repositories and repositories with no checked out revision. It is thus
the parent of root changesets and the effective ancestor when merging
unrelated changesets. Can be specified by the alias 'null' or by the
changeset ID '000000000000'.
Parent
See 'Changeset, parent'.
Parent changeset
See 'Changeset, parent'.
Parent, working directory
The working directory parent reflects a virtual revision which is the
child of the changeset (or two changesets with an uncommitted merge)
shown by "hg parents". This is changed with "hg update". Other
commands to see the working directory parent are "hg summary" and "hg
id". Can be specified by the alias ".".
Patch
(Noun) The product of a diff operation.
Example: "I've sent you my patch."
(Verb) The process of using a patch file to transform one changeset
into another.
Example: "You will need to patch that revision."
Phase
A per-changeset state tracking how the changeset has been or should be
shared. See "hg help phases".
Public
Changesets in the public phase have been shared with publishing
repositories and are therefore considered immutable. See "hg help
phases".
Pull
An operation in which changesets in a remote repository which are not
in the local repository are brought into the local repository. Note
that this operation without special arguments only updates the
repository, it does not update the files in the working directory. See
"hg help pull".
Push
An operation in which changesets in a local repository which are not
in a remote repository are sent to the remote repository. Note that
this operation only adds changesets which have been committed locally
to the remote repository. Uncommitted changes are not sent. See "hg
help push".
Repository
The metadata describing all recorded states of a collection of files.
Each recorded state is represented by a changeset. A repository is
usually (but not always) found in the ".hg" subdirectory of a working
directory. Any recorded state can be recreated by "updating" a working
directory to a specific changeset.
Repository head
See 'Head, repository'.
Revision
A state of the repository at some point in time. Earlier revisions can
be updated to by using "hg update". See also 'Revision number'; See
also 'Changeset'.
Revision number
This integer uniquely identifies a changeset in a specific repository.
It represents the order in which changesets were added to a
repository, starting with revision number 0. Note that the revision
number may be different in each clone of a repository. To identify
changesets uniquely between different clones, see 'Changeset id'.
Revlog
History storage mechanism used by Mercurial. It is a form of delta
encoding, with occasional full revision of data followed by delta of
each successive revision. It includes data and an index pointing to
the data.
Rewriting history
See 'History, rewriting'.
Root
A changeset that has only the null changeset as its parent. Most
repositories have only a single root changeset.
Secret
Changesets in the secret phase may not be shared via push, pull, or
clone. See "hg help phases".
Tag
An alternative name given to a changeset. Tags can be used in all
places where Mercurial expects a changeset ID, e.g., with "hg update".
The creation of a tag is stored in the history and will thus
automatically be shared with other using push and pull.
Tip
The changeset with the highest revision number. It is the changeset
most recently added in a repository.
Tip, branch
The head of a given branch with the highest revision number. When a
branch name is used as a revision identifier, it refers to the branch
tip. See also 'Branch, head'. Note that because revision numbers may
be different in different repository clones, the branch tip may be
different in different cloned repositories.
Update
(Noun) Another synonym of changeset.
Example: "I've pushed an update".
(Verb) This term is usually used to describe updating the state of the
working directory to that of a specific changeset. See "hg help
update".
Example: "You should update".
Working directory
See 'Directory, working'.
Working directory parent
See 'Parent, working directory'.