Diff for "ChangeSet"

Changeset

(for a short intro of the basic concepts of Mercurial, see UnderstandingMercurial)

A changeset (sometimes abbreviated "cset") is an atomic collection of changes to files in a [:Repository:repository]. It contains all recorded [:LocalModifications:local modfication] that lead to a new [:Revision:revision] of the repository.

A changeset is identified uniquely by a [:ChangeSetID:changeset ID]. In a single repository, you can identify it using a [:RevisionNumber:revision number].

The act of creating a changeset is called a [:Commit:commit] or checkin. The information in a changeset includes:

• the [:Nodeid:nodeid] of its [:Manifest:manifest]

• the list of changed files
• information about who made the change (the "committer"), why ("comments") and when (date/time, timezone)
• the name of the branch ("default", if omitted or not set)

Each changeset has zero, one or two [:Parent:parent] changesets. It has two parent changesets, if the commit was a [:Merge:merge]. It has no parent, if the changeset is a root in the repository. There may be multiple roots in a repository (normally, there is only one), each representing the start of a branch.

If a changeset is not the [:Head:head] of a branch, it has one or more child changesets (it is then the parent of its child changesets).

The [:WorkingDirectory:working directory] can be [:Update:updated] to any commited changeset of the repository, which then becomes the parent of the working directory.

"Updating" back to a changeset which already has a child, changeing files and then committing creates a new child changeset, thus starting a new branch. Branches can be [:NamedBranches:named].

All changesets of a repository are stored in the [:Changelog:changelog].

Here's what the internal representation of a changeset looks like:

$ hg debugdata .hg/00changelog.d 1208
1102691ceab8c8f278edecd80f2e3916090082dd <- the corresponding manifest nodeid
mpm@selenic.com <- the committer
1126146623 25200 <- the date, in seconds since the epoch, and seconds offset from UTC
mercurial/commands.py <- the list of changed files, followed by the commit message

Clean up local clone file list 

We now use an explicit list of files to copy during clone so that we
don't copy anything we shouldn't.

See also: ["ChangeSetComments"], ["Design"]

• Question: Is a changeset a particular state of the project (like a Subversion revision number), or is it a set of changes to files (like a Darcs patch)?

  • The way the changeset hash is calculated says that a changeset is a particular state of the project plus all of its ancestor states (i.e. all the changeset it took to get there). In Darcs that's a [http://www.darcs.net/manual/node7.html#SECTION00781000000000000000 tag].

CategoryGlossary