зеркало из https://github.com/microsoft/git.git
Merge branch 'master' of git://repo.or.cz/git/fastimport
* 'master' of git://repo.or.cz/git/fastimport: (81 commits) S_IFLNK != 0140000 Don't do non-fastforward updates in fast-import. Support RFC 2822 date parsing in fast-import. Minor fast-import documentation corrections. Remove unnecessary null pointer checks in fast-import. Correct fast-import timezone documentation. Correct minor style issue in fast-import. Correct compiler warnings in fast-import. Remove --branch-log from fast-import. Initial draft of fast-import documentation. Don't support shell-quoted refnames in fast-import. Reduce memory usage of fast-import. Include checkpoint command in the BNF. Accept 'inline' file data in fast-import commit structure. Reduce value duplication in t9300-fast-import. Create test case for fast-import. Support delimited data regions in fast-import. Remove unnecessary options from fast-import. Use fixed-size integers when writing out the index in fast-import. Always use struct pack_header for pack header in fast-import. ...
This commit is contained in:
Junio C Hamano
Коммит
41dc7e0044
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|
@ -36,6 +36,7 @@ git-diff-index
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|||
git-diff-stages
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git-diff-tree
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git-describe
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git-fast-import
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git-fetch
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git-fetch-pack
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git-findtags
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|
|
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|||
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@ -0,0 +1,739 @@
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|||
git-fast-import(1)
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||||
==================
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||||
|
||||
NAME
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||||
----
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||||
git-fast-import - Backend for fast Git data importers.
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||||
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||||
|
||||
SYNOPSIS
|
||||
--------
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||||
frontend | 'git-fast-import' [options]
|
||||
|
||||
DESCRIPTION
|
||||
-----------
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||||
This program is usually not what the end user wants to run directly.
|
||||
Most end users want to use one of the existing frontend programs,
|
||||
which parses a specific type of foreign source and feeds the contents
|
||||
stored there to git-fast-import (gfi).
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||||
|
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gfi reads a mixed command/data stream from standard input and
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||||
writes one or more packfiles directly into the current repository.
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||||
When EOF is received on standard input, fast import writes out
|
||||
updated branch and tag refs, fully updating the current repository
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with the newly imported data.
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The gfi backend itself can import into an empty repository (one that
|
||||
has already been initialized by gitlink:git-init[1]) or incrementally
|
||||
update an existing populated repository. Whether or not incremental
|
||||
imports are supported from a particular foreign source depends on
|
||||
the frontend program in use.
|
||||
|
||||
|
||||
OPTIONS
|
||||
-------
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||||
--date-format=<fmt>::
|
||||
Specify the type of dates the frontend will supply to
|
||||
gfi within `author`, `committer` and `tagger` commands.
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||||
See ``Date Formats'' below for details about which formats
|
||||
are supported, and their syntax.
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|
||||
--force::
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||||
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, expressed in MiB.
|
||||
The default is 4096 (4 GiB) as that is the maximum allowed
|
||||
packfile size (due to file format limitations). Some
|
||||
importers may wish to lower this, such as to ensure the
|
||||
resulting packfiles fit on CDs.
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||||
|
||||
--depth=<n>::
|
||||
Maximum delta depth, for blob and tree deltification.
|
||||
Default is 10.
|
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|
||||
--active-branches=<n>::
|
||||
Maximum number of branches to maintain active at once.
|
||||
See ``Memory Utilization'' below for details. Default is 5.
|
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|
||||
--export-marks=<file>::
|
||||
Dumps the internal marks table to <file> when complete.
|
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Marks are written one per line as `:markid SHA-1`.
|
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Frontends can use this file to validate imports after they
|
||||
have been completed.
|
||||
|
||||
Performance
|
||||
-----------
|
||||
The design of gfi allows it to import large projects in a minimum
|
||||
amount of memory usage and processing time. Assuming the frontend
|
||||
is able to keep up with gfi and feed it a constant stream of data,
|
||||
import times for projects holding 10+ years of history and containing
|
||||
100,000+ individual commits are generally completed in just 1-2
|
||||
hours on quite modest (~$2,000 USD) hardware.
|
||||
|
||||
Most bottlenecks appear to be in foreign source data access (the
|
||||
source just cannot extract revisions fast enough) or disk IO (gfi
|
||||
writes as fast as the disk will take the data). Imports will run
|
||||
faster if the source data is stored on a different drive than the
|
||||
destination Git repository (due to less IO contention).
|
||||
|
||||
|
||||
Development Cost
|
||||
----------------
|
||||
A typical frontend for gfi tends to weigh in at approximately 200
|
||||
lines of Perl/Python/Ruby code. Most developers have been able to
|
||||
create working importers in just a couple of hours, even though it
|
||||
is their first exposure to gfi, and sometimes even to Git. This is
|
||||
an ideal situation, given that most conversion tools are throw-away
|
||||
(use once, and never look back).
|
||||
|
||||
|
||||
Parallel Operation
|
||||
------------------
|
||||
Like `git-push` or `git-fetch`, imports handled by gfi are safe to
|
||||
run alongside parallel `git repack -a -d` or `git gc` invocations,
|
||||
or any other Git operation (including `git prune`, as loose objects
|
||||
are never used by gfi).
|
||||
|
||||
gfi does not lock the branch or tag refs it is actively importing.
|
||||
After the import, during its ref update phase, gfi tests each
|
||||
existing branch ref to verify the update will be a fast-forward
|
||||
update (the commit stored in the ref is contained in the new
|
||||
history of the commit to be written). If the update is not a
|
||||
fast-forward update, gfi will skip updating that ref and instead
|
||||
prints a warning message. gfi will always attempt to update all
|
||||
branch refs, and does not stop on the first failure.
|
||||
|
||||
Branch updates can be forced with `--force`, but its recommended that
|
||||
this only be used on an otherwise quiet repository. Using `--force`
|
||||
is not necessary for an initial import into an empty repository.
|
||||
|
||||
|
||||
Technical Discussion
|
||||
--------------------
|
||||
gfi tracks a set of branches in memory. Any branch can be created
|
||||
or modified at any point during the import process by sending a
|
||||
`commit` command on the input stream. This design allows a frontend
|
||||
program to process an unlimited number of branches simultaneously,
|
||||
generating commits in the order they are available from the source
|
||||
data. It also simplifies the frontend programs considerably.
|
||||
|
||||
gfi does not use or alter the current working directory, or any
|
||||
file within it. (It does however update the current Git repository,
|
||||
as referenced by `GIT_DIR`.) Therefore an import frontend may use
|
||||
the working directory for its own purposes, such as extracting file
|
||||
revisions from the foreign source. This ignorance of the working
|
||||
directory also allows gfi to run very quickly, as it does not
|
||||
need to perform any costly file update operations when switching
|
||||
between branches.
|
||||
|
||||
Input Format
|
||||
------------
|
||||
With the exception of raw file data (which Git does not interpret)
|
||||
the gfi input format is text (ASCII) based. This text based
|
||||
format simplifies development and debugging of frontend programs,
|
||||
especially when a higher level language such as Perl, Python or
|
||||
Ruby is being used.
|
||||
|
||||
gfi is very strict about its input. Where we say SP below we mean
|
||||
*exactly* one space. Likewise LF means one (and only one) linefeed.
|
||||
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 gfi when it encounters
|
||||
unexpected input.
|
||||
|
||||
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.
|
||||
|
||||
`raw`::
|
||||
This is the Git native format and is `<time> SP <tz>`.
|
||||
It is also gfi's default format, if `--date-format` was
|
||||
not specified.
|
||||
+
|
||||
The time of the event is specified by `<time>` as the number of
|
||||
seconds since the UNIX epoch (midnight, Jan 1, 1970, UTC) and is
|
||||
written as an ASCII decimal integer.
|
||||
+
|
||||
The timezone is specified by `<tz>` as a positive or negative offset
|
||||
from UTC. For example EST (which is typically 5 hours behind GMT)
|
||||
would be expressed in `<tz>` by ``-0500'' while GMT is ``+0000''.
|
||||
+
|
||||
If the timezone is not available in the source material, use
|
||||
``+0000'', or the most common local timezone. 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
|
||||
case the user's timezone can be easily assumed.
|
||||
+
|
||||
Unlike the `rfc2822` format, this format is very strict. Any
|
||||
variation in formatting will cause gfi to reject the value.
|
||||
|
||||
`rfc2822`::
|
||||
This is the standard email format as described by RFC 2822.
|
||||
+
|
||||
An example value is ``Tue Feb 6 11:22:18 2007 -0500''. The Git
|
||||
parser is accurate, but a little on the lenient side. Its the
|
||||
same parser used by gitlink:git-am[1] when applying patches
|
||||
received from email.
|
||||
+
|
||||
Some malformed strings may be accepted as valid dates. In some of
|
||||
these cases Git will still be able to obtain the correct date from
|
||||
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.
|
||||
+
|
||||
If the source material is formatted in RFC 2822 style dates,
|
||||
the frontend should let gfi handle the parsing and conversion
|
||||
(rather than attempting to do it itself) as the Git parser has
|
||||
been well tested in the wild.
|
||||
+
|
||||
Frontends should prefer the `raw` format if the source material
|
||||
is already in UNIX-epoch format, or is easily convertible to
|
||||
that format, as there is no ambiguity in parsing.
|
||||
|
||||
`now`::
|
||||
Always use the current time and timezone. The literal
|
||||
`now` must always be supplied for `<when>`.
|
||||
+
|
||||
This is a toy format. The current time and timezone of this system
|
||||
is always copied into the identity string at the time it is being
|
||||
created by gfi. There is no way to specify a different time or
|
||||
timezone.
|
||||
+
|
||||
This particular format is supplied as its short to implement and
|
||||
may be useful to a process that wants to create a new commit
|
||||
right now, without needing to use a working directory or
|
||||
gitlink:git-update-index[1].
|
||||
+
|
||||
If separate `author` and `committer` commands are used in a `commit`
|
||||
the timestamps may not match, as the system clock will be polled
|
||||
twice (once for each command). The only way to ensure that both
|
||||
author and committer identity information has the same timestamp
|
||||
is to omit `author` (thus copying from `committer`) or to use a
|
||||
date format other than `now`.
|
||||
|
||||
Commands
|
||||
~~~~~~~~
|
||||
gfi accepts several commands to update the current repository
|
||||
and control the current import process. More detailed discussion
|
||||
(with examples) of each command follows later.
|
||||
|
||||
`commit`::
|
||||
Creates a new branch or updates an existing branch by
|
||||
creating a new commit and updating the branch to point at
|
||||
the newly created commit.
|
||||
|
||||
`tag`::
|
||||
Creates an annotated tag object from an existing commit or
|
||||
branch. Lightweight tags are not supported by this command,
|
||||
as they are not recommended for recording meaningful points
|
||||
in time.
|
||||
|
||||
`reset`::
|
||||
Reset an existing branch (or a new branch) to a specific
|
||||
revision. This command must be used to change a branch to
|
||||
a specific revision without making a commit on it.
|
||||
|
||||
`blob`::
|
||||
Convert raw file data into a blob, for future use in a
|
||||
`commit` command. This command is optional and is not
|
||||
needed to perform an import.
|
||||
|
||||
`checkpoint`::
|
||||
Forces gfi to close the current packfile, generate its
|
||||
unique SHA-1 checksum and index, and start a new packfile.
|
||||
This command is optional and is not needed to perform
|
||||
an import.
|
||||
|
||||
`commit`
|
||||
~~~~~~~~
|
||||
Create or update a branch with a new commit, recording one logical
|
||||
change to the project.
|
||||
|
||||
....
|
||||
'commit' SP <ref> LF
|
||||
mark?
|
||||
('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)?
|
||||
(filemodify | filedelete)*
|
||||
LF
|
||||
....
|
||||
|
||||
where `<ref>` is the name of the branch to make the commit on.
|
||||
Typically branch names are prefixed with `refs/heads/` in
|
||||
Git, so importing the CVS branch symbol `RELENG-1_0` would use
|
||||
`refs/heads/RELENG-1_0` for the value of `<ref>`. The value of
|
||||
`<ref>` must be a valid refname in Git. As `LF` is not valid in
|
||||
a Git refname, no quoting or escaping syntax is supported here.
|
||||
|
||||
A `mark` command may optionally appear, requesting gfi to save a
|
||||
reference to the newly created commit for future use by the frontend
|
||||
(see below for format). It is very common for frontends to mark
|
||||
every commit they create, thereby allowing future branch creation
|
||||
from any imported commit.
|
||||
|
||||
The `data` command following `committer` must supply the commit
|
||||
message (see below for `data` command syntax). To import an empty
|
||||
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 gfi does not permit other encodings to be specified.
|
||||
|
||||
Zero or more `filemodify` and `filedelete` commands may be
|
||||
included to update the contents of the branch prior to the commit.
|
||||
These commands can be supplied in any order, gfi is not sensitive
|
||||
to pathname or operation ordering.
|
||||
|
||||
`author`
|
||||
^^^^^^^^
|
||||
An `author` command may optionally appear, if the author information
|
||||
might differ from the committer information. If `author` is omitted
|
||||
then gfi will automatically use the committer's information for
|
||||
the author portion of the commit. See below for a description of
|
||||
the fields in `author`, as they are identical to `committer`.
|
||||
|
||||
`committer`
|
||||
^^^^^^^^^^^
|
||||
The `committer` command indicates who made this commit, and when
|
||||
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)
|
||||
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.
|
||||
|
||||
The time of the change is specified by `<when>` using the date format
|
||||
that was selected by the `--date-format=<fmt>` command line option.
|
||||
See ``Date Formats'' above for the set of supported formats, and
|
||||
their syntax.
|
||||
|
||||
`from`
|
||||
^^^^^^
|
||||
Only valid for the first commit made on this branch by this
|
||||
gfi process. 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.
|
||||
|
||||
Omitting the `from` command in the first commit of a new branch will
|
||||
cause gfi to create that commit with no ancestor. This tends to be
|
||||
desired only for the initial commit of a project. Omitting the
|
||||
`from` command on existing branches is required, 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>`.
|
||||
|
||||
Here `<committish>` is any of the following:
|
||||
|
||||
* The name of an existing branch already in gfi's internal branch
|
||||
table. If gfi doesn't know the name, its treated as a SHA-1
|
||||
expression.
|
||||
|
||||
* A mark reference, `:<idnum>`, where `<idnum>` is the mark number.
|
||||
+
|
||||
The reason gfi uses `:` to denote a mark reference is this character
|
||||
is not legal in a Git branch name. The leading `:` makes it easy
|
||||
to distingush between the mark 42 (`:42`) and the branch 42 (`42`
|
||||
or `refs/heads/42`), or an abbreviated SHA-1 which happened to
|
||||
consist only of base-10 digits.
|
||||
+
|
||||
Marks must be declared (via `mark`) before they can be used.
|
||||
|
||||
* A complete 40 byte or abbreviated commit SHA-1 in hex.
|
||||
|
||||
* Any valid Git SHA-1 expression that resolves to a commit. See
|
||||
``SPECIFYING REVISIONS'' in gitlink:git-rev-parse[1] for details.
|
||||
|
||||
The special case of restarting an incremental import from the
|
||||
current branch value should be written as:
|
||||
----
|
||||
from refs/heads/branch^0
|
||||
----
|
||||
The `^0` suffix is necessary as gfi 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 `^0` will force
|
||||
gfi 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, and makes the current
|
||||
commit a merge commit. An unlimited number of `merge` commands per
|
||||
commit are permitted by gfi, 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.
|
||||
|
||||
Here `<committish>` is any of the commit specification expressions
|
||||
also accepted by `from` (see above).
|
||||
|
||||
`filemodify`
|
||||
^^^^^^^^^^^^
|
||||
Included in a `commit` command to add a new file or change the
|
||||
content of an existing file. This command has two different means
|
||||
of specifying the content of the file.
|
||||
|
||||
External data format::
|
||||
The data content for the file was already supplied by a prior
|
||||
`blob` command. The frontend just needs to connect it.
|
||||
+
|
||||
....
|
||||
'M' SP <mode> SP <dataref> SP <path> LF
|
||||
....
|
||||
+
|
||||
Here `<dataref>` can be either a mark reference (`:<idnum>`)
|
||||
set by a prior `blob` command, or a full 40-byte SHA-1 of an
|
||||
existing Git blob object.
|
||||
|
||||
Inline data format::
|
||||
The data content for the file has not been supplied yet.
|
||||
The frontend wants to supply it as part of this modify
|
||||
command.
|
||||
+
|
||||
....
|
||||
'M' SP <mode> SP 'inline' SP <path> LF
|
||||
data
|
||||
....
|
||||
+
|
||||
See below for a detailed description of the `data` command.
|
||||
|
||||
In both formats `<mode>` is the type of file entry, specified
|
||||
in octal. Git only supports the following modes:
|
||||
|
||||
* `100644` or `644`: A normal (not-executable) file. The majority
|
||||
of files in most projects use this mode. If in doubt, this is
|
||||
what you want.
|
||||
* `100755` or `755`: A normal, but executable, file.
|
||||
* `120000`: A symlink, the content of the file will be the link target.
|
||||
|
||||
In both formats `<path>` is the complete path of the file to be added
|
||||
(if not already existing) or modified (if already existing).
|
||||
|
||||
A `<path>` string must use UNIX-style directory seperators (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"`.
|
||||
|
||||
The value of `<path>` must be in canoncial form. That is it must not:
|
||||
|
||||
* contain an empty directory component (e.g. `foo//bar` is invalid),
|
||||
* end with a directory seperator (e.g. `foo/` is invalid),
|
||||
* start with a directory seperator (e.g. `/foo` is invalid),
|
||||
* contain the special component `.` or `..` (e.g. `foo/./bar` and
|
||||
`foo/../bar` are invalid).
|
||||
|
||||
It is recommended that `<path>` always be encoded using UTF-8.
|
||||
|
||||
`filedelete`
|
||||
^^^^^^^^^^^^
|
||||
Included in a `commit` command to remove a file from the branch.
|
||||
If the file removal makes its directory empty, the directory will
|
||||
be automatically removed too. This cascades up the tree until the
|
||||
first non-empty directory or the root is reached.
|
||||
|
||||
....
|
||||
'D' SP <path> LF
|
||||
....
|
||||
|
||||
here `<path>` is the complete path of the file to be removed.
|
||||
See `filemodify` above for a detailed description of `<path>`.
|
||||
|
||||
`mark`
|
||||
~~~~~~
|
||||
Arranges for gfi to save a reference to the current object, allowing
|
||||
the frontend to recall this object at a future point in time, without
|
||||
knowing its SHA-1. Here the current object is the object creation
|
||||
command the `mark` command appears within. This can be `commit`,
|
||||
`tag`, and `blob`, but `commit` is the most common usage.
|
||||
|
||||
....
|
||||
'mark' SP ':' <idnum> LF
|
||||
....
|
||||
|
||||
where `<idnum>` is the number assigned by the frontend to this mark.
|
||||
The value of `<idnum>` is expressed as an ASCII decimal integer.
|
||||
The value 0 is reserved and cannot be used as
|
||||
a mark. Only values greater than or equal to 1 may be used as marks.
|
||||
|
||||
New marks are created automatically. Existing marks can be moved
|
||||
to another object simply by reusing the same `<idnum>` in another
|
||||
`mark` command.
|
||||
|
||||
`tag`
|
||||
~~~~~
|
||||
Creates an annotated tag referring to a specific commit. To create
|
||||
lightweight (non-annotated) tags see the `reset` command below.
|
||||
|
||||
....
|
||||
'tag' SP <name> LF
|
||||
'from' SP <committish> LF
|
||||
'tagger' SP <name> SP LT <email> GT SP <when> LF
|
||||
data
|
||||
LF
|
||||
....
|
||||
|
||||
where `<name>` is the name of the tag to create.
|
||||
|
||||
Tag names are automatically prefixed with `refs/tags/` when stored
|
||||
in Git, so importing the CVS branch symbol `RELENG-1_0-FINAL` would
|
||||
use just `RELENG-1_0-FINAL` for `<name>`, and gfi will write the
|
||||
corresponding ref as `refs/tags/RELENG-1_0-FINAL`.
|
||||
|
||||
The value of `<name>` must be a valid refname in Git and therefore
|
||||
may contain forward slashes. As `LF` is not valid in a Git refname,
|
||||
no quoting or escaping syntax is supported here.
|
||||
|
||||
The `from` command is the same as in the `commit` command; see
|
||||
above for details.
|
||||
|
||||
The `tagger` command uses the same format as `committer` within
|
||||
`commit`; again see above for details.
|
||||
|
||||
The `data` command following `tagger` must supply the annotated tag
|
||||
message (see below for `data` command syntax). To import an empty
|
||||
tag message use a 0 length data. Tag messages are free-form and are
|
||||
not interpreted by Git. Currently they must be encoded in UTF-8,
|
||||
as gfi does not permit other encodings to be specified.
|
||||
|
||||
Signing annotated tags during import from within gfi is not
|
||||
supported. Trying to include your own PGP/GPG signature is not
|
||||
recommended, as the frontend does not (easily) have access to the
|
||||
complete set of bytes which normally goes into such a signature.
|
||||
If signing is required, create lightweight tags from within gfi with
|
||||
`reset`, then create the annotated versions of those tags offline
|
||||
with the standard gitlink:git-tag[1] process.
|
||||
|
||||
`reset`
|
||||
~~~~~~~
|
||||
Creates (or recreates) the named branch, optionally starting from
|
||||
a specific revision. The reset command allows a frontend to issue
|
||||
a new `from` command for an existing branch, or to create a new
|
||||
branch from an existing commit without creating a new commit.
|
||||
|
||||
....
|
||||
'reset' SP <ref> LF
|
||||
('from' SP <committish> LF)?
|
||||
LF
|
||||
....
|
||||
|
||||
For a detailed description of `<ref>` and `<committish>` see above
|
||||
under `commit` and `from`.
|
||||
|
||||
The `reset` command can also be used to create lightweight
|
||||
(non-annotated) tags. For example:
|
||||
|
||||
====
|
||||
reset refs/tags/938
|
||||
from :938
|
||||
====
|
||||
|
||||
would create the lightweight tag `refs/tags/938` referring to
|
||||
whatever commit mark `:938` references.
|
||||
|
||||
`blob`
|
||||
~~~~~~
|
||||
Requests writing one file revision to the packfile. The revision
|
||||
is not connected to any commit; this connection must be formed in
|
||||
a subsequent `commit` command by referencing the blob through an
|
||||
assigned mark.
|
||||
|
||||
....
|
||||
'blob' LF
|
||||
mark?
|
||||
data
|
||||
....
|
||||
|
||||
The mark command is optional here as some frontends have chosen
|
||||
to generate the Git SHA-1 for the blob on their own, and feed that
|
||||
directly to `commit`. This is typically more work than its worth
|
||||
however, as marks are inexpensive to store and easy to use.
|
||||
|
||||
`data`
|
||||
~~~~~~
|
||||
Supplies raw data (for use as blob/file content, commit messages, or
|
||||
annotated tag messages) to gfi. Data can be supplied using an exact
|
||||
byte count or delimited with a terminating line. Real frontends
|
||||
intended for production-quality conversions should always use the
|
||||
exact byte count format, as it is more robust and performs better.
|
||||
The delimited format is intended primarily for testing gfi.
|
||||
|
||||
Exact byte count format::
|
||||
The frontend must specify the number of bytes of data.
|
||||
+
|
||||
....
|
||||
'data' SP <count> LF
|
||||
<raw> LF
|
||||
....
|
||||
+
|
||||
where `<count>` is the exact number of bytes appearing within
|
||||
`<raw>`. The value of `<count>` is expressed as an ASCII decimal
|
||||
integer. The `LF` on either side of `<raw>` is not
|
||||
included in `<count>` and will not be included in the imported data.
|
||||
|
||||
Delimited format::
|
||||
A delimiter string is used to mark the end of the data.
|
||||
gfi will compute the length by searching for the delimiter.
|
||||
This format is primarly useful for testing and is not
|
||||
recommended for real data.
|
||||
+
|
||||
....
|
||||
'data' SP '<<' <delim> LF
|
||||
<raw> LF
|
||||
<delim> LF
|
||||
....
|
||||
+
|
||||
where `<delim>` is the chosen delimiter string. The string `<delim>`
|
||||
must not appear on a line by itself within `<raw>`, as otherwise
|
||||
gfi will think the data ends earlier than it really does. The `LF`
|
||||
immediately trailing `<raw>` is part of `<raw>`. This is one of
|
||||
the limitations of the delimited format, it is impossible to supply
|
||||
a data chunk which does not have an LF as its last byte.
|
||||
|
||||
`checkpoint`
|
||||
~~~~~~~~~~~~
|
||||
Forces gfi to close the current packfile and start a new one.
|
||||
As this requires a significant amount of CPU time and disk IO
|
||||
(to compute the overall pack SHA-1 checksum and generate the
|
||||
corresponding index file) it can easily take several minutes for
|
||||
a single `checkpoint` command to complete.
|
||||
|
||||
....
|
||||
'checkpoint' LF
|
||||
LF
|
||||
....
|
||||
|
||||
Packfile Optimization
|
||||
---------------------
|
||||
When packing a blob gfi always attempts to deltify against the last
|
||||
blob written. Unless specifically arranged for by the frontend,
|
||||
this will probably not be a prior version of the same file, so the
|
||||
generated delta will not be the smallest possible. The resulting
|
||||
packfile will be compressed, but will not be optimal.
|
||||
|
||||
Frontends which have efficient access to all revisions of a
|
||||
single file (for example reading an RCS/CVS ,v file) can choose
|
||||
to supply all revisions of that file as a sequence of consecutive
|
||||
`blob` commands. This allows gfi to deltify the different file
|
||||
revisions against each other, saving space in the final packfile.
|
||||
Marks can be used to later identify individual file revisions during
|
||||
a sequence of `commit` commands.
|
||||
|
||||
The packfile(s) created by gfi do not encourage good disk access
|
||||
patterns. This is caused by gfi writing the data in the order
|
||||
it is received on standard input, while Git typically organizes
|
||||
data within packfiles to make the most recent (current tip) data
|
||||
appear before historical data. Git also clusters commits together,
|
||||
speeding up revision traversal through better cache locality.
|
||||
|
||||
For this reason it is strongly recommended that users repack the
|
||||
repository with `git repack -a -d` after gfi completes, allowing
|
||||
Git to reorganize the packfiles for faster data access. If blob
|
||||
deltas are suboptimal (see above) then also adding the `-f` option
|
||||
to force recomputation of all deltas can significantly reduce the
|
||||
final packfile size (30-50% smaller can be quite typical).
|
||||
|
||||
Memory Utilization
|
||||
------------------
|
||||
There are a number of factors which affect how much memory gfi
|
||||
requires to perform an import. Like critical sections of core
|
||||
Git, gfi uses its own memory allocators to ammortize any overheads
|
||||
associated with malloc. In practice gfi tends to ammoritize any
|
||||
malloc overheads to 0, due to its use of large block allocations.
|
||||
|
||||
per object
|
||||
~~~~~~~~~~
|
||||
gfi maintains an in-memory structure for every object written in
|
||||
this execution. On a 32 bit system the structure is 32 bytes,
|
||||
on a 64 bit system the structure is 40 bytes (due to the larger
|
||||
pointer sizes). Objects in the table are not deallocated until
|
||||
gfi terminates. Importing 2 million objects on a 32 bit system
|
||||
will require approximately 64 MiB of memory.
|
||||
|
||||
The object table is actually a hashtable keyed on the object name
|
||||
(the unique SHA-1). This storage configuration allows gfi to reuse
|
||||
an existing or already written object and avoid writing duplicates
|
||||
to the output packfile. Duplicate blobs are surprisingly common
|
||||
in an import, typically due to branch merges in the source.
|
||||
|
||||
per mark
|
||||
~~~~~~~~
|
||||
Marks are stored in a sparse array, using 1 pointer (4 bytes or 8
|
||||
bytes, depending on pointer size) per mark. Although the array
|
||||
is sparse, frontends are still strongly encouraged to use marks
|
||||
between 1 and n, where n is the total number of marks required for
|
||||
this import.
|
||||
|
||||
per branch
|
||||
~~~~~~~~~~
|
||||
Branches are classified as active and inactive. The memory usage
|
||||
of the two classes is significantly different.
|
||||
|
||||
Inactive branches are stored in a structure which uses 96 or 120
|
||||
bytes (32 bit or 64 bit systems, respectively), plus the length of
|
||||
the branch name (typically under 200 bytes), per branch. gfi will
|
||||
easily handle as many as 10,000 inactive branches in under 2 MiB
|
||||
of memory.
|
||||
|
||||
Active branches have the same overhead as inactive branches, but
|
||||
also contain copies of every tree that has been recently modified on
|
||||
that branch. If subtree `include` has not been modified since the
|
||||
branch became active, its contents will not be loaded into memory,
|
||||
but if subtree `src` has been modified by a commit since the branch
|
||||
became active, then its contents will be loaded in memory.
|
||||
|
||||
As active branches store metadata about the files contained on that
|
||||
branch, their in-memory storage size can grow to a considerable size
|
||||
(see below).
|
||||
|
||||
gfi automatically moves active branches to inactive status based on
|
||||
a simple least-recently-used algorithm. The LRU chain is updated on
|
||||
each `commit` command. The maximum number of active branches can be
|
||||
increased or decreased on the command line with `--active-branches=`.
|
||||
|
||||
per active tree
|
||||
~~~~~~~~~~~~~~~
|
||||
Trees (aka directories) use just 12 bytes of memory on top of the
|
||||
memory required for their entries (see ``per active file'' below).
|
||||
The cost of a tree is virtually 0, as its overhead ammortizes out
|
||||
over the individual file entries.
|
||||
|
||||
per active file entry
|
||||
~~~~~~~~~~~~~~~~~~~~~
|
||||
Files (and pointers to subtrees) within active trees require 52 or 64
|
||||
bytes (32/64 bit platforms) per entry. To conserve space, file and
|
||||
tree names are pooled in a common string table, allowing the filename
|
||||
``Makefile'' to use just 16 bytes (after including the string header
|
||||
overhead) no matter how many times it occurs within the project.
|
||||
|
||||
The active branch LRU, when coupled with the filename string pool
|
||||
and lazy loading of subtrees, allows gfi to efficiently import
|
||||
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>.
|
||||
|
||||
GIT
|
||||
---
|
||||
Part of the gitlink:git[7] suite
|
||||
|
||||
1
Makefile
1
Makefile
|
|
@ -194,6 +194,7 @@ SCRIPTS = $(patsubst %.sh,%,$(SCRIPT_SH)) \
|
|||
PROGRAMS = \
|
||||
git-convert-objects$X git-fetch-pack$X git-fsck$X \
|
||||
git-hash-object$X git-index-pack$X git-local-fetch$X \
|
||||
git-fast-import$X \
|
||||
git-merge-base$X \
|
||||
git-daemon$X \
|
||||
git-merge-index$X git-mktag$X git-mktree$X git-patch-id$X \
|
||||
|
|
|
|||
Разница между файлами не показана из-за своего большого размера
Загрузить разницу
|
|
@ -0,0 +1,359 @@
|
|||
#!/bin/sh
|
||||
#
|
||||
# Copyright (c) 2007 Shawn Pearce
|
||||
#
|
||||
|
||||
test_description='test git-fast-import utility'
|
||||
. ./test-lib.sh
|
||||
. ../diff-lib.sh ;# test-lib chdir's into trash
|
||||
|
||||
file2_data='file2
|
||||
second line of EOF'
|
||||
|
||||
file3_data='EOF
|
||||
in 3rd file
|
||||
END'
|
||||
|
||||
file4_data=abcd
|
||||
file4_len=4
|
||||
|
||||
file5_data='an inline file.
|
||||
we should see it later.'
|
||||
|
||||
file6_data='#!/bin/sh
|
||||
echo "$@"'
|
||||
|
||||
###
|
||||
### series A
|
||||
###
|
||||
|
||||
test_tick
|
||||
cat >input <<INPUT_END
|
||||
blob
|
||||
mark :2
|
||||
data <<EOF
|
||||
$file2_data
|
||||
EOF
|
||||
|
||||
blob
|
||||
mark :3
|
||||
data <<END
|
||||
$file3_data
|
||||
END
|
||||
|
||||
blob
|
||||
mark :4
|
||||
data $file4_len
|
||||
$file4_data
|
||||
commit refs/heads/master
|
||||
mark :5
|
||||
committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
|
||||
data <<COMMIT
|
||||
initial
|
||||
COMMIT
|
||||
|
||||
M 644 :2 file2
|
||||
M 644 :3 file3
|
||||
M 755 :4 file4
|
||||
|
||||
INPUT_END
|
||||
test_expect_success \
|
||||
'A: create pack from stdin' \
|
||||
'git-fast-import --export-marks=marks.out <input &&
|
||||
git-whatchanged master'
|
||||
test_expect_success \
|
||||
'A: verify pack' \
|
||||
'for p in .git/objects/pack/*.pack;do git-verify-pack $p||exit;done'
|
||||
|
||||
cat >expect <<EOF
|
||||
author $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
|
||||
committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
|
||||
|
||||
initial
|
||||
EOF
|
||||
test_expect_success \
|
||||
'A: verify commit' \
|
||||
'git-cat-file commit master | sed 1d >actual &&
|
||||
diff -u expect actual'
|
||||
|
||||
cat >expect <<EOF
|
||||
100644 blob file2
|
||||
100644 blob file3
|
||||
100755 blob file4
|
||||
EOF
|
||||
test_expect_success \
|
||||
'A: verify tree' \
|
||||
'git-cat-file -p master^{tree} | sed "s/ [0-9a-f]* / /" >actual &&
|
||||
diff -u expect actual'
|
||||
|
||||
echo "$file2_data" >expect
|
||||
test_expect_success \
|
||||
'A: verify file2' \
|
||||
'git-cat-file blob master:file2 >actual && diff -u expect actual'
|
||||
|
||||
echo "$file3_data" >expect
|
||||
test_expect_success \
|
||||
'A: verify file3' \
|
||||
'git-cat-file blob master:file3 >actual && diff -u expect actual'
|
||||
|
||||
printf "$file4_data" >expect
|
||||
test_expect_success \
|
||||
'A: verify file4' \
|
||||
'git-cat-file blob master:file4 >actual && diff -u expect actual'
|
||||
|
||||
cat >expect <<EOF
|
||||
:2 `git-rev-parse --verify master:file2`
|
||||
:3 `git-rev-parse --verify master:file3`
|
||||
:4 `git-rev-parse --verify master:file4`
|
||||
:5 `git-rev-parse --verify master^0`
|
||||
EOF
|
||||
test_expect_success \
|
||||
'A: verify marks output' \
|
||||
'diff -u expect marks.out'
|
||||
|
||||
###
|
||||
### series B
|
||||
###
|
||||
|
||||
test_tick
|
||||
cat >input <<INPUT_END
|
||||
commit refs/heads/branch
|
||||
mark :1
|
||||
committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
|
||||
data <<COMMIT
|
||||
corrupt
|
||||
COMMIT
|
||||
|
||||
from refs/heads/master
|
||||
M 755 0000000000000000000000000000000000000001 zero1
|
||||
|
||||
INPUT_END
|
||||
test_expect_failure \
|
||||
'B: fail on invalid blob sha1' \
|
||||
'git-fast-import <input'
|
||||
rm -f .git/objects/pack_* .git/objects/index_*
|
||||
|
||||
###
|
||||
### series C
|
||||
###
|
||||
|
||||
newf=`echo hi newf | git-hash-object -w --stdin`
|
||||
oldf=`git-rev-parse --verify master:file2`
|
||||
test_tick
|
||||
cat >input <<INPUT_END
|
||||
commit refs/heads/branch
|
||||
committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
|
||||
data <<COMMIT
|
||||
second
|
||||
COMMIT
|
||||
|
||||
from refs/heads/master
|
||||
M 644 $oldf file2/oldf
|
||||
M 755 $newf file2/newf
|
||||
D file3
|
||||
|
||||
INPUT_END
|
||||
test_expect_success \
|
||||
'C: incremental import create pack from stdin' \
|
||||
'git-fast-import <input &&
|
||||
git-whatchanged branch'
|
||||
test_expect_success \
|
||||
'C: verify pack' \
|
||||
'for p in .git/objects/pack/*.pack;do git-verify-pack $p||exit;done'
|
||||
test_expect_success \
|
||||
'C: validate reuse existing blob' \
|
||||
'test $newf = `git-rev-parse --verify branch:file2/newf`
|
||||
test $oldf = `git-rev-parse --verify branch:file2/oldf`'
|
||||
|
||||
cat >expect <<EOF
|
||||
parent `git-rev-parse --verify master^0`
|
||||
author $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
|
||||
committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
|
||||
|
||||
second
|
||||
EOF
|
||||
test_expect_success \
|
||||
'C: verify commit' \
|
||||
'git-cat-file commit branch | sed 1d >actual &&
|
||||
diff -u expect actual'
|
||||
|
||||
cat >expect <<EOF
|
||||
:000000 100755 0000000000000000000000000000000000000000 f1fb5da718392694d0076d677d6d0e364c79b0bc A file2/newf
|
||||
:100644 100644 7123f7f44e39be127c5eb701e5968176ee9d78b1 7123f7f44e39be127c5eb701e5968176ee9d78b1 R100 file2 file2/oldf
|
||||
:100644 000000 0d92e9f3374ae2947c23aa477cbc68ce598135f1 0000000000000000000000000000000000000000 D file3
|
||||
EOF
|
||||
git-diff-tree -M -r master branch >actual
|
||||
test_expect_success \
|
||||
'C: validate rename result' \
|
||||
'compare_diff_raw expect actual'
|
||||
|
||||
###
|
||||
### series D
|
||||
###
|
||||
|
||||
test_tick
|
||||
cat >input <<INPUT_END
|
||||
commit refs/heads/branch
|
||||
committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
|
||||
data <<COMMIT
|
||||
third
|
||||
COMMIT
|
||||
|
||||
from refs/heads/branch^0
|
||||
M 644 inline newdir/interesting
|
||||
data <<EOF
|
||||
$file5_data
|
||||
EOF
|
||||
|
||||
M 755 inline newdir/exec.sh
|
||||
data <<EOF
|
||||
$file6_data
|
||||
EOF
|
||||
|
||||
INPUT_END
|
||||
test_expect_success \
|
||||
'D: inline data in commit' \
|
||||
'git-fast-import <input &&
|
||||
git-whatchanged branch'
|
||||
test_expect_success \
|
||||
'D: verify pack' \
|
||||
'for p in .git/objects/pack/*.pack;do git-verify-pack $p||exit;done'
|
||||
|
||||
cat >expect <<EOF
|
||||
:000000 100755 0000000000000000000000000000000000000000 35a59026a33beac1569b1c7f66f3090ce9c09afc A newdir/exec.sh
|
||||
:000000 100644 0000000000000000000000000000000000000000 046d0371e9220107917db0d0e030628de8a1de9b A newdir/interesting
|
||||
EOF
|
||||
git-diff-tree -M -r branch^ branch >actual
|
||||
test_expect_success \
|
||||
'D: validate new files added' \
|
||||
'compare_diff_raw expect actual'
|
||||
|
||||
echo "$file5_data" >expect
|
||||
test_expect_success \
|
||||
'D: verify file5' \
|
||||
'git-cat-file blob branch:newdir/interesting >actual &&
|
||||
diff -u expect actual'
|
||||
|
||||
echo "$file6_data" >expect
|
||||
test_expect_success \
|
||||
'D: verify file6' \
|
||||
'git-cat-file blob branch:newdir/exec.sh >actual &&
|
||||
diff -u expect actual'
|
||||
|
||||
###
|
||||
### series E
|
||||
###
|
||||
|
||||
cat >input <<INPUT_END
|
||||
commit refs/heads/branch
|
||||
author $GIT_AUTHOR_NAME <$GIT_AUTHOR_EMAIL> Tue Feb 6 11:22:18 2007 -0500
|
||||
committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> Tue Feb 6 12:35:02 2007 -0500
|
||||
data <<COMMIT
|
||||
RFC 2822 type date
|
||||
COMMIT
|
||||
|
||||
from refs/heads/branch^0
|
||||
|
||||
INPUT_END
|
||||
test_expect_failure \
|
||||
'E: rfc2822 date, --date-format=raw' \
|
||||
'git-fast-import --date-format=raw <input'
|
||||
test_expect_success \
|
||||
'E: rfc2822 date, --date-format=rfc2822' \
|
||||
'git-fast-import --date-format=rfc2822 <input'
|
||||
test_expect_success \
|
||||
'E: verify pack' \
|
||||
'for p in .git/objects/pack/*.pack;do git-verify-pack $p||exit;done'
|
||||
|
||||
cat >expect <<EOF
|
||||
author $GIT_AUTHOR_NAME <$GIT_AUTHOR_EMAIL> 1170778938 -0500
|
||||
committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> 1170783302 -0500
|
||||
|
||||
RFC 2822 type date
|
||||
EOF
|
||||
test_expect_success \
|
||||
'E: verify commit' \
|
||||
'git-cat-file commit branch | sed 1,2d >actual &&
|
||||
diff -u expect actual'
|
||||
|
||||
###
|
||||
### series F
|
||||
###
|
||||
|
||||
old_branch=`git-rev-parse --verify branch^0`
|
||||
test_tick
|
||||
cat >input <<INPUT_END
|
||||
commit refs/heads/branch
|
||||
committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
|
||||
data <<COMMIT
|
||||
losing things already?
|
||||
COMMIT
|
||||
|
||||
from refs/heads/branch~1
|
||||
|
||||
reset refs/heads/other
|
||||
from refs/heads/branch
|
||||
|
||||
INPUT_END
|
||||
test_expect_success \
|
||||
'F: non-fast-forward update skips' \
|
||||
'if git-fast-import <input
|
||||
then
|
||||
echo BAD gfi did not fail
|
||||
return 1
|
||||
else
|
||||
if test $old_branch = `git-rev-parse --verify branch^0`
|
||||
then
|
||||
: branch unaffected and failure returned
|
||||
return 0
|
||||
else
|
||||
echo BAD gfi changed branch $old_branch
|
||||
return 1
|
||||
fi
|
||||
fi
|
||||
'
|
||||
test_expect_success \
|
||||
'F: verify pack' \
|
||||
'for p in .git/objects/pack/*.pack;do git-verify-pack $p||exit;done'
|
||||
|
||||
cat >expect <<EOF
|
||||
tree `git-rev-parse branch~1^{tree}`
|
||||
parent `git-rev-parse branch~1`
|
||||
author $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
|
||||
committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
|
||||
|
||||
losing things already?
|
||||
EOF
|
||||
test_expect_success \
|
||||
'F: verify other commit' \
|
||||
'git-cat-file commit other >actual &&
|
||||
diff -u expect actual'
|
||||
|
||||
###
|
||||
### series G
|
||||
###
|
||||
|
||||
old_branch=`git-rev-parse --verify branch^0`
|
||||
test_tick
|
||||
cat >input <<INPUT_END
|
||||
commit refs/heads/branch
|
||||
committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
|
||||
data <<COMMIT
|
||||
losing things already?
|
||||
COMMIT
|
||||
|
||||
from refs/heads/branch~1
|
||||
|
||||
INPUT_END
|
||||
test_expect_success \
|
||||
'G: non-fast-forward update forced' \
|
||||
'git-fast-import --force <input'
|
||||
test_expect_success \
|
||||
'G: verify pack' \
|
||||
'for p in .git/objects/pack/*.pack;do git-verify-pack $p||exit;done'
|
||||
test_expect_success \
|
||||
'G: branch changed, but logged' \
|
||||
'test $old_branch != `git-rev-parse --verify branch^0` &&
|
||||
test $old_branch = `git-rev-parse --verify branch@{1}`'
|
||||
|
||||
test_done
|
||||
Загрузка…
Ссылка в новой задаче