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Diffstat (limited to 'Documentation/git-fast-import.txt')
| -rw-r--r-- | Documentation/git-fast-import.txt | 99 |
1 files changed, 85 insertions, 14 deletions
diff --git a/Documentation/git-fast-import.txt b/Documentation/git-fast-import.txt index 249249aac7..2620d28b4b 100644 --- a/Documentation/git-fast-import.txt +++ b/Documentation/git-fast-import.txt @@ -8,6 +8,7 @@ git-fast-import - Backend for fast Git data importers SYNOPSIS -------- +[verse] frontend | 'git fast-import' [options] DESCRIPTION @@ -97,9 +98,16 @@ OPTIONS options. --cat-blob-fd=<fd>:: - Specify the file descriptor that will be written to - when the `cat-blob` command is encountered in the stream. - The default behaviour is to write to `stdout`. + 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 @@ -330,6 +338,11 @@ and control the current import process. More detailed discussion 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 @@ -413,8 +426,8 @@ Here `<name>` is the person's display name (for example (``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. @@ -466,9 +479,9 @@ current branch value should be written as: ---- 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. @@ -648,9 +661,14 @@ paths for a commit are encouraged to do so. `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 @@ -925,6 +943,9 @@ 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 @@ -958,7 +979,7 @@ Reading from a named tree:: See `filemodify` above for a detailed description of `<path>`. -Output uses the same format as `git ls-tree <tree> {litdd} <path>`: +Output uses the same format as `git ls-tree <tree> -- <path>`: ==== <mode> SP ('blob' | 'tree' | 'commit') SP <dataref> HT <path> LF @@ -974,6 +995,9 @@ 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 @@ -995,10 +1019,14 @@ force:: (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:: @@ -1015,6 +1043,11 @@ notes:: 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. `option` ~~~~~~~~ @@ -1044,6 +1077,44 @@ not be passed as option: * 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 |