diff options
Diffstat (limited to 'Documentation/revisions.txt')
| -rw-r--r-- | Documentation/revisions.txt | 68 |
1 files changed, 56 insertions, 12 deletions
diff --git a/Documentation/revisions.txt b/Documentation/revisions.txt index 013f0de798..d85e303364 100644 --- 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 @@ -23,7 +23,7 @@ blobs contained in a commit. A symbolic ref name. E.g. 'master' typically means the commit object referenced by 'refs/heads/master'. If you happen to have both 'heads/master' and 'tags/master', you can - explicitly say 'heads/master' to tell git which one you mean. + explicitly say 'heads/master' to tell Git which one you mean. When ambiguous, a '<refname>' is disambiguated by taking the first match in the following rules: @@ -55,9 +55,12 @@ when you run `git cherry-pick`. + Note that any of the 'refs/*' cases above may come either from the '$GIT_DIR/refs' directory or from the '$GIT_DIR/packed-refs' file. -While the ref name encoding is unspecified, UTF-8 is prefered as +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 @@ -85,13 +88,40 @@ some output processing may assume ref names in UTF-8. branch 'blabla' then '@\{1\}' means the same as 'blabla@\{1\}'. '@\{-<n>\}', e.g. '@\{-1\}':: - The construct '@\{-<n>\}' means the <n>th branch checked out + The construct '@\{-<n>\}' means the <n>th branch/commit checked out before the current one. '<branchname>@\{upstream\}', e.g. 'master@\{upstream\}', '@\{u\}':: The suffix '@\{upstream\}' to a branchname (short form '<branchname>@\{u\}') refers to the branch that the branch specified by branchname is set to build on - top of. A missing branchname defaults to the current one. + top of (configured with `branch.<name>.remote` and + `branch.<name>.merge`). A missing branchname defaults to the + current one. + +'<branchname>@\{push\}', e.g. 'master@\{push\}', '@\{push\}':: + The suffix '@\{push}' reports the branch "where we would push to" if + `git push` were run while `branchname` was checked out (or the current + 'HEAD' if no branchname is specified). Since our push destination is + in a remote repository, of course, we report the local tracking branch + that corresponds to that branch (i.e., something in 'refs/remotes/'). ++ +Here's an example to make it more clear: ++ +------------------------------ +$ git config push.default current +$ git config remote.pushdefault myfork +$ git checkout -b mybranch origin/master + +$ git rev-parse --symbolic-full-name @{upstream} +refs/remotes/origin/master + +$ git rev-parse --symbolic-full-name @{push} +refs/remotes/myfork/mybranch +------------------------------ ++ +Note in the example that we set up a triangular workflow, where we pull +from one location and push to another. In a non-triangular workflow, +'@\{push}' is the same as '@\{upstream}', and there is no need for it. '<rev>{caret}', e.g. 'HEAD{caret}, v1.5.1{caret}0':: A suffix '{caret}' to a revision parameter means the first parent of @@ -111,11 +141,23 @@ some output processing may assume ref names in UTF-8. '<rev>{caret}\{<type>\}', e.g. 'v0.99.8{caret}\{commit\}':: A suffix '{caret}' followed by an object type name enclosed in - brace pair means the object - could be a tag, and dereference the tag recursively until an - object of that type is found or the object cannot be - dereferenced anymore (in which case, barf). '<rev>{caret}0' + brace pair means dereference the object at '<rev>' recursively until + an object of type '<type>' is found or the object cannot be + dereferenced anymore (in which case, barf). + For example, if '<rev>' is a commit-ish, '<rev>{caret}\{commit\}' + describes the corresponding commit object. + Similarly, if '<rev>' is a tree-ish, '<rev>{caret}\{tree\}' + describes the corresponding tree object. + '<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}\{tag\}' can be used to ensure that 'rev' identifies an +existing tag object. '<rev>{caret}\{\}', e.g. 'v0.99.8{caret}\{\}':: A suffix '{caret}' followed by an empty brace pair @@ -239,11 +281,13 @@ 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 |