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Diffstat (limited to 'Documentation/git-fast-import.txt')
| -rw-r--r-- | Documentation/git-fast-import.txt | 220 |
1 files changed, 138 insertions, 82 deletions
diff --git a/Documentation/git-fast-import.txt b/Documentation/git-fast-import.txt index ec6ef31197..690fed3ea4 100644 --- a/Documentation/git-fast-import.txt +++ b/Documentation/git-fast-import.txt @@ -33,34 +33,46 @@ the frontend program in use. OPTIONS ------- ---date-format=<fmt>:: - Specify the type of dates the frontend will supply to - fast-import within `author`, `committer` and `tagger` commands. - See ``Date Formats'' below for details about which formats - are supported, and their syntax. --force:: Force updating modified existing branches, even if doing so would cause commits to be lost (as the new commit does not contain the old commit). ---max-pack-size=<n>:: - Maximum size of each output packfile. - The default is unlimited. +--quiet:: + Disable all non-fatal output, making fast-import silent when it + is successful. This option disables the output shown by + \--stats. ---big-file-threshold=<n>:: - Maximum size of a blob that fast-import will attempt to - create a delta for, expressed in bytes. The default is 512m - (512 MiB). Some importers may wish to lower this on systems - with constrained memory. +--stats:: + Display some basic statistics about the objects fast-import has + created, the packfiles they were stored into, and the + memory used by fast-import during this run. Showing this output + is currently the default, but can be disabled with \--quiet. ---depth=<n>:: - Maximum delta depth, for blob and tree deltification. - Default is 10. +Options for Frontends +~~~~~~~~~~~~~~~~~~~~~ ---active-branches=<n>:: - Maximum number of branches to maintain active at once. - See ``Memory Utilization'' below for details. Default is 5. +--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. + +--date-format=<fmt>:: + Specify the type of dates the frontend will supply to + fast-import within `author`, `committer` and `tagger` commands. + 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. This option might be useful for detecting errors + that cause the frontend to terminate before it has started to + write a stream. + +Locations of Marks Files +~~~~~~~~~~~~~~~~~~~~~~~~ --export-marks=<file>:: Dumps the internal marks table to <file> when complete. @@ -83,30 +95,33 @@ OPTIONS Like --import-marks but instead of erroring out, silently skips the file if it does not exist. ---relative-marks:: +--[no-]relative-marks:: 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 to the .git/info/fast-import directory. However, other importers may use a different location. ++ +Relative and non-relative marks may be combined by interweaving +--(no-)-relative-marks with the --(import|export)-marks= options. ---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= - options. +Performance and Compression Tuning +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ---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`. +--active-branches=<n>:: + Maximum number of branches to maintain active at once. + See ``Memory Utilization'' below for details. Default is 5. ---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. +--big-file-threshold=<n>:: + Maximum size of a blob that fast-import will attempt to + create a delta for, expressed in bytes. The default is 512m + (512 MiB). Some importers may wish to lower this on systems + with constrained memory. + +--depth=<n>:: + Maximum delta depth, for blob and tree deltification. + Default is 10. --export-pack-edges=<file>:: After creating a packfile, print a line of data to @@ -117,16 +132,9 @@ OPTIONS as these commits can be used as edge points during calls to 'git pack-objects'. ---quiet:: - Disable all non-fatal output, making fast-import silent when it - is successful. This option disables the output shown by - \--stats. - ---stats:: - Display some basic statistics about the objects fast-import has - created, the packfiles they were stored into, and the - memory used by fast-import during this run. Showing this output - is currently the default, but can be disabled with \--quiet. +--max-pack-size=<n>:: + Maximum size of each output packfile. + The default is unlimited. Performance @@ -223,7 +231,7 @@ Date Formats ~~~~~~~~~~~~ The following date formats are supported. A frontend should select the format it will use for this import by passing the format name -in the \--date-format=<fmt> command line option. +in the \--date-format=<fmt> command-line option. `raw`:: This is the Git native format and is `<time> SP <offutc>`. @@ -243,7 +251,7 @@ advisement to help formatting routines display the timestamp. If the local offset is not available in the source material, use ``+0000'', or the most common local offset. For example many organizations have a CVS repository which has only ever been accessed -by users who are located in the same location and timezone. In this +by users who are located in the same location and time zone. In this case a reasonable offset from UTC could be assumed. + Unlike the `rfc2822` format, this format is very strict. Any @@ -263,7 +271,7 @@ the malformed string. There are also some types of malformed strings which Git will parse wrong, and yet consider valid. Seriously malformed strings will be rejected. + -Unlike the `raw` format above, the timezone/UTC offset information +Unlike the `raw` format above, the time zone/UTC offset information contained in an RFC 2822 date string is used to adjust the date value to UTC prior to storage. Therefore it is important that this information be as accurate as possible. @@ -279,13 +287,13 @@ format, or its format is easily convertible to it, as there is no ambiguity in parsing. `now`:: - Always use the current time and timezone. The literal + Always use the current time and time zone. The literal `now` must always be supplied for `<when>`. + -This is a toy format. The current time and timezone of this system +This is a toy format. The current time and time zone of this system is always copied into the identity string at the time it is being created by fast-import. There is no way to specify a different time or -timezone. +time zone. + This particular format is supplied as it's short to implement and may be useful to a process that wants to create a new commit @@ -340,7 +348,7 @@ and control the current import process. More detailed discussion `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. + `--done` command-line option or `feature done` command. `cat-blob`:: Causes fast-import to print a blob in 'cat-file --batch' @@ -353,8 +361,8 @@ and control the current import process. More detailed discussion `--cat-blob-fd` or `stdout` if unspecified. `feature`:: - Require that fast-import supports the specified feature, or - abort if it does not. + Enable the specified feature. This requires that fast-import + supports the specified feature, and aborts if it does not. `option`:: Specify any of the options listed under OPTIONS that do not @@ -372,8 +380,8 @@ change to the project. ('author' (SP <name>)? SP LT <email> GT SP <when> LF)? 'committer' (SP <name>)? SP LT <email> GT SP <when> LF data - ('from' SP <committish> LF)? - ('merge' SP <committish> LF)? + ('from' SP <commit-ish> LF)? + ('merge' SP <commit-ish> LF)? (filemodify | filedelete | filecopy | filerename | filedeleteall | notemodify)* LF? .... @@ -422,14 +430,14 @@ they made it. Here `<name>` is the person's display name (for example ``Com M Itter'') and `<email>` is the person's email address -(``cm@example.com''). `LT` and `GT` are the literal less-than (\x3c) +(``\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>` 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. +that was selected by the \--date-format=<fmt> command-line option. See ``Date Formats'' above for the set of supported formats, and their syntax. @@ -437,7 +445,9 @@ their syntax. ^^^^^^ The `from` command is used to specify the commit to initialize this branch from. This revision will be the first ancestor of the -new commit. +new commit. The state of the tree built at this commit will begin +with the state at the `from` commit, and be altered by the content +modifications in this commit. Omitting the `from` command in the first commit of a new branch will cause fast-import to create that commit with no ancestor. This @@ -450,9 +460,9 @@ as the current commit on that branch is automatically assumed to be the first ancestor of the new commit. As `LF` is not valid in a Git refname or SHA-1 expression, no -quoting or escaping syntax is supported within `<committish>`. +quoting or escaping syntax is supported within `<commit-ish>`. -Here `<committish>` is any of the following: +Here `<commit-ish>` is any of the following: * The name of an existing branch already in fast-import's internal branch table. If fast-import doesn't know the name, it's treated as a SHA-1 @@ -473,31 +483,32 @@ Marks must be declared (via `mark`) before they can be used. * Any valid Git SHA-1 expression that resolves to a commit. See ``SPECIFYING REVISIONS'' in linkgit:gitrevisions[7] for details. +* The special null SHA-1 (40 zeros) specifies that the branch is to be + removed. + The special case of restarting an incremental import from the 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. `merge` ^^^^^^^ -Includes one additional ancestor commit. If the `from` command is +Includes one additional ancestor commit. The additional ancestry +link does not change the way the tree state is built at this commit. +If the `from` command is omitted when creating a new branch, the first `merge` commit will be the first ancestor of the current commit, and the branch will start out with no files. An unlimited number of `merge` commands per commit are permitted by fast-import, thereby establishing an n-way merge. -However Git's other tools never create commits with more than 15 -additional ancestors (forming a 16-way merge). For this reason -it is suggested that frontends do not use more than 15 `merge` -commands per commit; 16, if starting a new, empty branch. -Here `<committish>` is any of the commit specification expressions +Here `<commit-ish>` is any of the commit specification expressions also accepted by `from` (see above). `filemodify` @@ -553,8 +564,12 @@ A `<path>` string must use UNIX-style directory separators (forward slash `/`), may contain any byte other than `LF`, and must not start with double quote (`"`). -If an `LF` or double quote must be encoded into `<path>` shell-style -quoting should be used, e.g. `"path/with\n and \" in it"`. +A path can use C-style string quoting; this is accepted in all cases +and mandatory if the filename starts with double quote or contains +`LF`. In C-style quoting, the complete name should be surrounded with +double quotes, and any `LF`, backslash, or double quote characters +must be escaped by preceding them with a backslash (e.g., +`"path/with\n, \\ and \" in it"`). The value of `<path>` must be in canonical form. That is it must not: @@ -661,8 +676,8 @@ paths for a commit are encouraged to do so. `notemodify` ^^^^^^^^^^^^ 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>` +annotating a `<commit-ish>` or change this annotation contents. +Internally it is similar to filemodify 100644 on `<commit-ish>` 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. @@ -675,7 +690,7 @@ External data format:: commit that is to be annotated. + .... - 'N' SP <dataref> SP <committish> LF + 'N' SP <dataref> SP <commit-ish> LF .... + Here `<dataref>` can be either a mark reference (`:<idnum>`) @@ -688,13 +703,13 @@ Inline data format:: command. + .... - 'N' SP 'inline' SP <committish> LF + 'N' SP 'inline' SP <commit-ish> LF data .... + See below for a detailed description of the `data` command. -In both formats `<committish>` is any of the commit specification +In both formats `<commit-ish>` is any of the commit specification expressions also accepted by `from` (see above). `mark` @@ -725,7 +740,7 @@ lightweight (non-annotated) tags see the `reset` command below. .... 'tag' SP <name> LF - 'from' SP <committish> LF + 'from' SP <commit-ish> LF 'tagger' (SP <name>)? SP LT <email> GT SP <when> LF data .... @@ -770,11 +785,11 @@ branch from an existing commit without creating a new commit. .... 'reset' SP <ref> LF - ('from' SP <committish> LF)? + ('from' SP <commit-ish> LF)? LF? .... -For a detailed description of `<ref>` and `<committish>` see above +For a detailed description of `<ref>` and `<commit-ish>` see above under `commit` and `from`. The `LF` after the command is optional (it used to be required). @@ -942,6 +957,9 @@ 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 @@ -975,7 +993,7 @@ 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 @@ -991,6 +1009,9 @@ 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 @@ -1040,7 +1061,9 @@ 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. + 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` ~~~~~~~~ @@ -1061,7 +1084,7 @@ Option commands must be the first commands on the input (not counting feature commands), to give an option command after any non-option command is an error. -The following commandline options change import semantics and may therefore +The following command-line options change import semantics and may therefore not be passed as option: * date-format @@ -1075,10 +1098,39 @@ not be passed as option: 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 +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 @@ -1385,6 +1437,10 @@ 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. +SEE ALSO +-------- +linkgit:git-fast-export[1] + GIT --- Part of the linkgit:git[1] suite |