--------------------
A revision parameter '<rev>' typically, but not necessarily, names a
-commit object. It uses what is called an 'extended SHA1'
+commit object. It uses what is called an 'extended SHA-1'
syntax. Here are various ways to spell object names. The
ones listed near the end of this list name trees and
blobs contained in a commit.
'<sha1>', e.g. 'dae86e1950b1277e545cee180551750029cfe735', 'dae86e'::
- The full SHA1 object name (40-byte hexadecimal string), or
+ The full SHA-1 object name (40-byte hexadecimal string), or
a leading substring that is unique within the repository.
E.g. dae86e1950b1277e545cee180551750029cfe735 and dae86e both
name the same commit object if there is no other object in
object of that type is found or the object cannot be
dereferenced anymore (in which case, barf). '<rev>{caret}0'
is a short-hand for '<rev>{caret}\{commit\}'.
++
+'rev{caret}\{object\}' can be used to make sure 'rev' names an
+object that exists, without requiring 'rev' to be a tag, and
+without dereferencing 'rev'; because a tag is already an object,
+it does not have to be dereferenced even once to get to an object.
'<rev>{caret}\{\}', e.g. 'v0.99.8{caret}\{\}'::
A suffix '{caret}' followed by an empty brace pair