|
Size: 1299
Comment: links
|
Size: 1334
Comment: added french translation link
|
| Deletions are marked like this. | Additions are marked like this. |
| Line 5: | Line 5: |
| [http://en.wikipedia.org/wiki/SHA_hash_functions SHA1 hash function], | [[http://en.wikipedia.org/wiki/SHA_hash_functions|SHA1 hash function]], |
| Line 7: | Line 7: |
| modify a file, [:Commit:commit] the change, and then modify it to restore the | modify a file, [[Commit|commit]] the change, and then modify it to restore the |
| Line 11: | Line 11: |
| concatentation of the [:Parent:parent] nodeids with the file's contents. | concatentation of the [[Parent|parent]] nodeids with the file's contents. |
| Line 20: | Line 20: |
| ''Note: The short-form notation for SHA1 hash values in Mercurial is | ''Note: The short-form notation for SHA1 hash values in Mercurial is |
| Line 23: | Line 23: |
| as it is unambiguous (see also ["ChangeSetID"]).'' | as it is unambiguous (see also [[ChangeSetID]]).'' |
| Line 26: | Line 26: |
| as the empty root [:Revision:revision]. This has the nice property that otherwise | as the empty root [[Revision|revision]]. This has the nice property that otherwise |
| Line 29: | Line 29: |
| Nodeids are used in [:Revlog:revlogs]. | Nodeids are used in [[Revlog|revlogs]]. [[FrenchNodeid|Français]] |
Nodeids
Nodeids are unique ids that represent the contents of a file and its position in the project history. For now they are computed using the SHA1 hash function, which generates 160 bits (40 hex digits). If you modify a file, commit the change, and then modify it to restore the original contents, the contents are the same but the history is different, so the file will get a new nodeid. This history-sensitivity is obtained by calculating the nodeid from the concatentation of the parent nodeids with the file's contents.
Nodeids are typically presented to the user as shortened hex strings, like this:
$ hg id 8d43f8c0b836 tip
Note: The short-form notation for SHA1 hash values in Mercurial is the substring of the first 12 characters of the hex string representation of the full SHA1 value. The short form can also be entered in commands, as long as it is unambiguous (see also ChangeSetID).
The nodeid 00000... is special and is known as the nullid. It serves as the empty root revision. This has the nice property that otherwise unrelated revisions have a common empty ancestor.
Nodeids are used in revlogs.