Merge branch 'fc/at-head'

diff --git a/Documentation/revisions.txt b/Documentation/revisions.txt
index b0f72206a09ffe6a703d923756b86c4964c1ad88..09896a37b1a7b735b0defc9d2c7eb2a14cc713ab 100644 (file)
--- a/Documentation/revisions.txt
+++ b/Documentation/revisions.txt
@@ -2,13 +2,13 @@ SPECIFYING REVISIONS
 --------------------
 
 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
@@ -58,6 +58,9 @@ the '$GIT_DIR/refs' directory or from the '$GIT_DIR/packed-refs' file.
 While the ref name encoding is unspecified, UTF-8 is preferred as
 some output processing may assume ref names in UTF-8.
 
+'@'::
+  '@' alone is a shortcut for 'HEAD'.
+
 '<refname>@\{<date>\}', e.g. 'master@\{yesterday\}', 'HEAD@\{5 minutes ago\}'::
   A ref followed by the suffix '@' with a date specification
   enclosed in a brace
@@ -116,6 +119,11 @@ some output processing may assume ref names in UTF-8.
   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
@@ -239,11 +247,13 @@ To summarize:
 
 '<rev1>..<rev2>'::
        Include commits that are reachable from <rev2> but exclude
-       those that are reachable from <rev1>.
+       those that are reachable from <rev1>.  When either <rev1> or
+       <rev2> is omitted, it defaults to 'HEAD'.
 
 '<rev1>\...<rev2>'::
        Include commits that are reachable from either <rev1> or
-       <rev2> but exclude those that are reachable from both.
+       <rev2> but exclude those that are reachable from both.  When
+       either <rev1> or <rev2> is omitted, it defaults to 'HEAD'.
 
 '<rev>{caret}@', e.g. 'HEAD{caret}@'::
   A suffix '{caret}' followed by an at sign is the same as listing