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'.

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 'Changeset, close'.

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.

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`.

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."

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.

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'.