SYNOPSIS
--------
+[verse]
frontend | 'git fast-import' [options]
DESCRIPTION
See ``Date Formats'' below for details about which formats
are supported, and their syntax.
+-- done::
+ Terminate with error if there is no 'done' command at the
+ end of the stream.
+
--force::
Force updating modified existing branches, even if doing
so would cause commits to be lost (as the new commit does
set of marks. If a mark is defined to different values,
the last file wins.
+--import-marks-if-exists=<file>::
+ Like --import-marks but instead of erroring out, silently
+ skips the file if it does not exist.
+
--relative-marks::
- After specifying --relative-marks= the paths specified
+ After specifying --relative-marks the paths specified
with --import-marks= and --export-marks= are relative
to an internal directory in the current repository.
In git-fast-import this means that the paths are relative
--no-relative-marks::
Negates a previous --relative-marks. Allows for combining
relative and non-relative marks by interweaving
- --(no-)-relative-marks= with the --(import|export)-marks=
+ --(no-)-relative-marks with the --(import|export)-marks=
options.
+--cat-blob-fd=<fd>::
+ Write responses to `cat-blob` and `ls` queries to the
+ file descriptor <fd> instead of `stdout`. Allows `progress`
+ output intended for the end-user to be separated from other
+ output.
+
+--done::
+ Require a `done` command at the end of the stream.
+ This option might be useful for detecting errors that
+ cause the frontend to terminate before it has started to
+ write a stream.
+
--export-pack-edges=<file>::
After creating a packfile, print a line of data to
<file> listing the filename of the packfile and the last
Ruby is being used.
fast-import is very strict about its input. Where we say SP below we mean
-*exactly* one space. Likewise LF means one (and only one) linefeed.
+*exactly* one space. Likewise LF means one (and only one) linefeed
+and HT one (and only one) horizontal tab.
Supplying additional whitespace characters will cause unexpected
results, such as branch names or file names with leading or trailing
spaces in their name, or early termination of fast-import when it encounters
standard output. This command is optional and is not needed
to perform an import.
+`done`::
+ Marks the end of the stream. This command is optional
+ unless the `done` feature was requested using the
+ `--done` command line option or `feature done` command.
+
+`cat-blob`::
+ Causes fast-import to print a blob in 'cat-file --batch'
+ format to the file descriptor set with `--cat-blob-fd` or
+ `stdout` if unspecified.
+
+`ls`::
+ Causes fast-import to print a line describing a directory
+ entry in 'ls-tree' format to the file descriptor set with
+ `--cat-blob-fd` or `stdout` if unspecified.
+
`feature`::
Require that fast-import supports the specified feature, or
abort if it does not.
(``cm@example.com''). `LT` and `GT` are the literal less-than (\x3c)
and greater-than (\x3e) symbols. These are required to delimit
the email address from the other fields in the line. Note that
-`<name>` is free-form and may contain any sequence of bytes, except
-`LT` and `LF`. It is typically UTF-8 encoded.
+`<name>` and `<email>` are free-form and may contain any sequence
+of bytes, except `LT`, `GT` and `LF`. `<name>` is typically UTF-8 encoded.
The time of the change is specified by `<when>` using the date format
that was selected by the \--date-format=<fmt> command line option.
----
from refs/heads/branch^0
----
-The `{caret}0` suffix is necessary as fast-import does not permit a branch to
+The `^0` suffix is necessary as fast-import does not permit a branch to
start from itself, and the branch is created in memory before the
-`from` command is even read from the input. Adding `{caret}0` will force
+`from` command is even read from the input. Adding `^0` will force
fast-import to resolve the commit through Git's revision parsing library,
rather than its internal branch table, thereby loading in the
existing value of the branch.
* contain the special component `.` or `..` (e.g. `foo/./bar` and
`foo/../bar` are invalid).
+The root of the tree can be represented by an empty string as `<path>`.
+
It is recommended that `<path>` always be encoded using UTF-8.
`filedelete`
`notemodify`
^^^^^^^^^^^^
-Included in a `commit` command to add a new note (annotating a given
-commit) or change the content of an existing note. This command has
-two different means of specifying the content of the note.
+Included in a `commit` `<notes_ref>` command to add a new note
+annotating a `<committish>` or change this annotation contents.
+Internally it is similar to filemodify 100644 on `<committish>`
+path (maybe split into subdirectories). It's not advised to
+use any other commands to write to the `<notes_ref>` tree except
+`filedeleteall` to delete all existing notes in this tree.
+This command has two different means of specifying the content
+of the note.
External data format::
The data content for the note was already supplied by a prior
inform the reader when the `checkpoint` has been completed and it
can safely access the refs that fast-import updated.
+`cat-blob`
+~~~~~~~~~~
+Causes fast-import to print a blob to a file descriptor previously
+arranged with the `--cat-blob-fd` argument. The command otherwise
+has no impact on the current import; its main purpose is to
+retrieve blobs that may be in fast-import's memory but not
+accessible from the target repository.
+
+....
+ 'cat-blob' SP <dataref> LF
+....
+
+The `<dataref>` can be either a mark reference (`:<idnum>`)
+set previously or a full 40-byte SHA-1 of a Git blob, preexisting or
+ready to be written.
+
+Output uses the same format as `git cat-file --batch`:
+
+====
+ <sha1> SP 'blob' SP <size> LF
+ <contents> LF
+====
+
+This command can be used anywhere in the stream that comments are
+accepted. In particular, the `cat-blob` command can be used in the
+middle of a commit but not in the middle of a `data` command.
+
+See ``Responses To Commands'' below for details about how to read
+this output safely.
+
+`ls`
+~~~~
+Prints information about the object at a path to a file descriptor
+previously arranged with the `--cat-blob-fd` argument. This allows
+printing a blob from the active commit (with `cat-blob`) or copying a
+blob or tree from a previous commit for use in the current one (with
+`filemodify`).
+
+The `ls` command can be used anywhere in the stream that comments are
+accepted, including the middle of a commit.
+
+Reading from the active commit::
+ This form can only be used in the middle of a `commit`.
+ The path names a directory entry within fast-import's
+ active commit. The path must be quoted in this case.
++
+....
+ 'ls' SP <path> LF
+....
+
+Reading from a named tree::
+ The `<dataref>` can be a mark reference (`:<idnum>`) or the
+ full 40-byte SHA-1 of a Git tag, commit, or tree object,
+ preexisting or waiting to be written.
+ The path is relative to the top level of the tree
+ named by `<dataref>`.
++
+....
+ 'ls' SP <dataref> SP <path> LF
+....
+
+See `filemodify` above for a detailed description of `<path>`.
+
+Output uses the same format as `git ls-tree <tree> -- <path>`:
+
+====
+ <mode> SP ('blob' | 'tree' | 'commit') SP <dataref> HT <path> LF
+====
+
+The <dataref> represents the blob, tree, or commit object at <path>
+and can be used in later 'cat-blob', 'filemodify', or 'ls' commands.
+
+If there is no file or subtree at that path, 'git fast-import' will
+instead report
+
+====
+ missing SP <path> LF
+====
+
+See ``Responses To Commands'' below for details about how to read
+this output safely.
+
`feature`
~~~~~~~~~
Require that fast-import supports the specified feature, or abort if
(see OPTIONS, above).
import-marks::
+import-marks-if-exists::
Like --import-marks except in two respects: first, only one
- "feature import-marks" command is allowed per stream;
- second, an --import-marks= command-line option overrides
- any "feature import-marks" command in the stream.
+ "feature import-marks" or "feature import-marks-if-exists"
+ command is allowed per stream; second, an --import-marks=
+ or --import-marks-if-exists command-line option overrides
+ any of these "feature" commands in the stream; third,
+ "feature import-marks-if-exists" like a corresponding
+ command-line option silently skips a nonexistent file.
+
+cat-blob::
+ls::
+ Require that the backend support the 'cat-blob' or 'ls' command.
+ Versions of fast-import not supporting the specified command
+ will exit with a message indicating so.
+ This lets the import error out early with a clear message,
+ rather than wasting time on the early part of an import
+ before the unsupported command is detected.
notes::
Require that the backend support the 'notemodify' (N)
Versions of fast-import not supporting notes will exit
with a message indicating so.
+done::
+ Error out if the stream ends without a 'done' command.
+ Without this feature, errors causing the frontend to end
+ abruptly at a convenient point in the stream can go
+ undetected. This may occur, for example, if an import
+ front end dies in mid-operation without emitting SIGTERM
+ or SIGKILL at its subordinate git fast-import instance.
+
`option`
~~~~~~~~
Processes the specified option so that git fast-import behaves in a
* date-format
* import-marks
* export-marks
+* cat-blob-fd
* force
+`done`
+~~~~~~
+If the `done` feature is not in use, treated as if EOF was read.
+This can be used to tell fast-import to finish early.
+
+If the `--done` command line option or `feature done` command is
+in use, the `done` command is mandatory and marks the end of the
+stream.
+
+Responses To Commands
+---------------------
+New objects written by fast-import are not available immediately.
+Most fast-import commands have no visible effect until the next
+checkpoint (or completion). The frontend can send commands to
+fill fast-import's input pipe without worrying about how quickly
+they will take effect, which improves performance by simplifying
+scheduling.
+
+For some frontends, though, it is useful to be able to read back
+data from the current repository as it is being updated (for
+example when the source material describes objects in terms of
+patches to be applied to previously imported objects). This can
+be accomplished by connecting the frontend and fast-import via
+bidirectional pipes:
+
+====
+ mkfifo fast-import-output
+ frontend <fast-import-output |
+ git fast-import >fast-import-output
+====
+
+A frontend set up this way can use `progress`, `ls`, and `cat-blob`
+commands to read information from the import in progress.
+
+To avoid deadlock, such frontends must completely consume any
+pending output from `progress`, `ls`, and `cat-blob` before
+performing writes to fast-import that might block.
+
Crash Reports
-------------
If fast-import is supplied invalid input it will terminate with a
projects with 2,000+ branches and 45,114+ files in a very limited
memory footprint (less than 2.7 MiB per active branch).
-
-Author
-------
-Written by Shawn O. Pearce <spearce@spearce.org>.
-
-Documentation
---------------
-Documentation by Shawn O. Pearce <spearce@spearce.org>.
+Signals
+-------
+Sending *SIGUSR1* to the 'git fast-import' process ends the current
+packfile early, simulating a `checkpoint` command. The impatient
+operator can use this facility to peek at the objects and refs from an
+import in progress, at the cost of some added running time and worse
+compression.
GIT
---