unpack-trees.c: assume submodules are clean during check-out

diff --git a/Documentation/git-fast-import.txt b/Documentation/git-fast-import.txt
index 80a8ee0f1c37720c632d0df2d628241c1e35938c..30ee98d17f537e289c08d94d9b43728a4b147a34 100644 (file)
--- a/Documentation/git-fast-import.txt
+++ b/Documentation/git-fast-import.txt
@@ -302,7 +302,7 @@ change to the project.
        data
        ('from' SP <committish> LF)?
        ('merge' SP <committish> LF)?
-       (filemodify | filedelete | filerename | filedeleteall)*
+       (filemodify | filedelete | filecopy | filerename | filedeleteall)*
        LF
 ....
 
@@ -325,13 +325,13 @@ commit message use a 0 length data.  Commit messages are free-form
 and are not interpreted by Git.  Currently they must be encoded in
 UTF-8, as fast-import does not permit other encodings to be specified.
 
-Zero or more `filemodify`, `filedelete`, `filename` and
-`filedeleteall` commands
+Zero or more `filemodify`, `filedelete`, `filecopy`, `filerename`
+and `filedeleteall` commands
 may be included to update the contents of the branch prior to
 creating the commit.  These commands may be supplied in any order.
 However it is recommended that a `filedeleteall` command preceed
-all `filemodify` and `filerename` commands in the same commit, as
-`filedeleteall`
+all `filemodify`, `filecopy` and `filerename` commands in the same
+commit, as `filedeleteall`
 wipes the branch clean (see below).
 
 `author`
@@ -497,6 +497,27 @@ here `<path>` is the complete path of the file or subdirectory to
 be removed from the branch.
 See `filemodify` above for a detailed description of `<path>`.
 
+`filecopy`
+^^^^^^^^^^^^
+Recursively copies an existing file or subdirectory to a different
+location within the branch.  The existing file or directory must
+exist.  If the destination exists it will be completely replaced
+by the content copied from the source.
+
+....
+       'C' SP <path> SP <path> LF
+....
+
+here the first `<path>` is the source location and the second
+`<path>` is the destination.  See `filemodify` above for a detailed
+description of what `<path>` may look like.  To use a source path
+that contains SP the path must be quoted.
+
+A `filecopy` command takes effect immediately.  Once the source
+location has been copied to the destination any future commands
+applied to the source location will not impact the destination of
+the copy.
+
 `filerename`
 ^^^^^^^^^^^^
 Renames an existing file or subdirectory to a different location
@@ -517,6 +538,15 @@ location has been renamed to the destination any future commands
 applied to the source location will create new files there and not
 impact the destination of the rename.
 
+Note that a `filerename` is the same as a `filecopy` followed by a
+`filedelete` of the source location.  There is a slight performance
+advantage to using `filerename`, but the advantage is so small
+that it is never worth trying to convert a delete/add pair in
+source material into a rename for fast-import.  This `filerename`
+command is provided just to simplify frontends that already have
+rename information and don't want bother with decomposing it into a
+`filecopy` followed by a `filedelete`.
+
 `filedeleteall`
 ^^^^^^^^^^^^^^^
 Included in a `commit` command to remove all files (and also all