== Changeset ID ==

A '''changeset ID''' is a 160-bit
identifier that uniquely describes a [[ChangeSet|changeset]] and its position in the
change history of a [[Repository|repository]], regardless of which machine or repository it's on. This is
represented to the user as a 40 digit hexadecimal number. Technically, a changeset ID is a [[Nodeid|nodeid]].

=== Short-form changeset IDs ===

Since a 40 digit hex number is unwieldy, Mercurial will accept any unambiguous prefix of a changeset ID as shorthand for that ID.

When printing a changeset ID, Mercurial usually prints just the first twelve characters.  This is called the "short form" of the ID.

'''Note''': a short-form ID can start out valid, but become invalid because another changeset with the same prefix shows up later on.  Do not use short-form I``Ds for long-lived representations. You can use the `--debug` option to display the full changeset ID. For example:
{{{
$ hg --debug tags
tip                                1:1ef7872431f9c64908c732f0bcd4db5700b4cb70
test-tag                           0:1438e82fac1c2191394e67257b7b94e05c7caa2f
}}}

=== Revision numbers are shorthand ===

Within a single repository, you can use a [[RevisionNumber|revision number]] as shorthand for a changeset ID.

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CategoryGlossary

[[FrenchChangeSetID|Français]]