repocutter - Man Page

repocutter [-q] [-d n] [-i 'filename'] [-r 'selection'] 'subcommand'

This program does surgical and filtering operations on Subversion dump files.  While it is is not as flexible as reposurgeon(1), it can perform Subversion-specific transformations that reposurgeon cannot, and can be useful for processing Subversion repositories into a form suitable for conversion. Also, it supports the version 3 dumpfile format, which reposurgeon does not.

In most commands, the -r (or --range) option limits the selection of revisions over which an operation will be performed. Usually other revisions will be passed through unaltered, except in the select and deselect commands for which the option controls which revisions will be passed through. A selection consists of one or more comma-separated ranges. A range may consist of an integer revision number or the special name HEAD for the head revision. Or it may be a colon-separated pair of integers, or an integer followed by a colon followed by HEAD.

If the output stream contains copyfrom references to missing revisions, repocutter silently patch each copysources by stepping it backwards to the most recent previous version that exists.

(Older versions of this tool, before 4.30, treated -r as an implied selection filter rather than passing through unselected revisions unaltered. If you have old scripts using repocutter they may need modification.)

Normally, each subcommand produces a progress spinner on standard error; each turn means another revision has been filtered. The -q (or --quiet) option suppresses this. Quiet mode is set when output is redirected to a file or pipe.

The -d option enables debug messages on standard error. It takes an integer debug level. These messages are probably only of interest to repocutter developers.

The -i option sets the input source to a specified filename. This is primarily useful when running the program under a debugger. When this option is not present the program expects to read a stream from standard input.

Generally, if you need to use this program at all, you will find that you need to pipe your dump file through multiple instances of it doing one kind of operation each.  This is not as expensive as it sounds; with the exception of the reduce subcommand, the working set of this program is bounded by the size of the the largest single blob plus its metadata.  It does not need to hold the entire repo metadata in memory.

The -f/-fixed option disables regexp compilation of PATTERN arguments, treating them as literal strings.

The -t option sets a tag to be included in error and warning messages. This will be useful for determining which stage of a multistage repocutter pipeline failed.

There are a few other command-specific options described under individual commands.

In the command descriptions, PATTERN arguments are regular expressions to match pathnames, constrained so that each match must be a path segment or a sequence of path segments; that is, the left end must be either at the start of path or immediately following a /, and the right end must precede a / or be at end of string.  With a leading ^ the match is constrained to be a leading sequence of the pathname; with a trailing $, a trailing one.

The following subcommands are available:

select

The 'select' subcommand selects a range and permits only revisions and nodes in that range to pass to standard output.  A range beginning with 0 includes the dumpfile header. Mergeinfo properties in all revisions are updated so they no longer refer to omitted revisions.

Warning::valid dump that can be read by reposurgeon. In particular, it may delete a revision that is referenced in a later copy-from operation, which will crash reposurgeon.

deselect

The 'deselect' subcommand selects a range and permits only revisions and nodes NOT in that range to pass to standard output.  Any mergeinfo properties in other revisions are updated so they no longer refer to dropped revisions.

Warning::valid dump that can be read by reposurgeon. In particular, it may delete a revision that is referenced in a later copy-from operation, which will crash reposurgeon.

see

Render a very condensed report on the repository node structure, mainly useful for examining strange and pathological repositories.  File content is ignored.  You get one line per repository operation, reporting the revision, operation type, file path, and the copy source (if any). Directory paths are distinguished by a trailing slash.  The 'copy' operation is really an 'add' with a directory source and target; the display name is changed to make them easier to see. This report can be restricted by a selection set.

renumber

Renumber all revisions, patching Node-copyfrom headers as required. Any selection option is ignored. Takes no arguments.  The -b option can be used to set the base to renumber from, defaulting to 0.

count

The 'count' subcommand lists the last revision number in the input stream. This is normally the revision count, buut may not if the stream has omitted revisions.

log

Generate a log report, same format as the output of svn log on a repository, to standard output.

setlog

Replace the log entries in the input dumpfile with the corresponding entries in the LOGFILE, which should be in the format of an svn log output. Replacements may be restricted to a specified range.

propdel

Delete the property PROPNAME. May be restricted by a revision selection. You may specify multiple properties to be deleted.

proprename

Rename the property OLDNAME to NEWNAME. May be restricted by a revision selection. You may specify multiple properties to be renamed.

propset

Set the property PROPNAME to PROPVAL.

May be restricted by a revision selection. Note that specifying only a revision will cause the property  to be seet on the revision properties and on all nodes in the rtevision; you’ll probably want to specify a node index.

You may specify multiple property settings.

propclean

Every path with a suffix matching one of SUFFIXES gets a property turned off.  The default property is svn::Another property may be set with the -p option.

expunge

Delete all operations with Node-path or Node-copyfrom-path headers matching specified Golang regular expressions (opposite of 'sift').  Any revision left with no Node records after this filtering has its Revision record dropped as well. Mergeinfo properties in all revisions are updated so they no longer refer to dropped revisions.

Warning::valid dump that can be read by reposurgeon. In particular, it may delete a revision that is referenced in a later copy-from operation, which will crash reposurgeon.

sift

Delete all operations with either Node-path or Node-copyfrom-path headers not matching specified Golang regular expressions (opposite of 'expunge'). Any revision left with no Node records after this filtering has its Revision record removed as well. Mergeinfo properties in all revisions are updated so they no longer refer to dropped revisions.

This transform can be restricted by a selection set.

Warning::valid dump that can be read by reposurgeon. In particular, it may delete a revision that is referenced in a later copy-from operation, which will crash reposurgeon.

closure

The 'closure' subcommand computes the transitive closure of a path set under the relation 'copies from' - that is, with the smallest set of additional paths such that every copy-from source is in the set.

pathlist

List all distinct node-paths in the stream, once each, in the order first encountered.

pathrename

Modify Node-path headers, Node-copyfrom-path headers, and svn::expression FROM; replace with TO.  TO may contain Golang-style backreferences (${1}, ${2} etc - curly brackets not optional) to parenthesized portions of FROM.

Matches are constrained so that each match must be a path segment or a sequence of path segments; that is, the left end must be either at the start of path or immediately following a /, and the right end must precede a / or be at end of string.  With a leading ^ the match is constrained to be a leading sequence of the pathname; with a trailing $, a trailing one.

Multiple FROM/TO pairs may be specified and are applied in order. This transform can be restricted by a selection set.

All mergeinfo properties are updated in accordance with the path renames,

setpath

In the specified revisions, replace the Node-path with the specified PATH. Does not alter mergeinfo properties as a side effect.

setcopyfrom

In the specified revisions, replace the Node-copyfrom-path with the specified PATH. Does not alter mergeinfo properties as a side effect.  Terminates with error if any selected node is not a copy.

pop

Pop initial segment off each path matching PATTERN - by default, all paths.

May be useful after a sift command to turn a dump from a subproject stripped from a dump for a multiple-project repository into the normal form with trunk/tags/branches at the top level.

This transform cannot be restricted by a selection set, as it is not possible to guarantee that copyfro paths and mergeinfo properties will be modified consistently in the presence of that kind of restriction.

Mergeinfo properties in all revisions are updated, as well as path and copyfrom parts.

push

Push an initial segment onto each matching path. Normally used to add a "trunk" prefix to every path in a flat repository.  The -s option can be used rton set a different initial segment.

This transform cannot be restricted by a selection set, as it is not possible to guarantee that copyfro paths and mergeinfo properties will be modified consistently in the presence of that kind of restriction.

Mergeinfo properties in all revisions are updated toi refer to the new pathnames.

filecopy

For each node in the revision range, stash the current version of the node-path’s content.  For each later file copy operation with that source, replace the file copy with an explicit add/change using the stashed content.

You can use this operation to sever links from obsolete branches or non-conformable directories in a multiproject repository so the unwanted content can be expunged without changing the content of later revisions.

If a PATTERN argument is provided, only replace copies with an explicit add/change when the source node path matches PATTERN.

With the -n flag, only the basename is required to match PATTERN if it is provided. Otherwise, with -n and no PATTERN, require a match of source to target on basename only rather than the full path. This may be required in order to extract filecopies from branches.

Restricting the range holds down the memory requirement of this tool, which in the worst (and default) 1:$ case will keep a copy of every blob in the repository until it’s done processing the stream.

skipcopy

Replace the source revision and path of a copy at the upper end of the selection with the source revisions and path of a copy at the lower end. Fails unless both revisions are copies.  Used to remove an unwanted intermediate copy or copies, cleaning up the history.

swap

Swap the top two elements of each pathname in every revision in the selection set. Useful following a sift operation for straightening out a common form of multi-project repository.  If a PATTERN argument is given, only paths matching it are swapped.

swapsvn

Like swap, but is aware of Subversion structure.  Used for transforming multiproject repositories into a standard layout with trunk, tags, and branches at the top level.

Fires when the second component of a matching path is "trunk", "branches", or "tags", or the path consists of a single segment that is a top-level project directory; passes through all paths for this is not so unaltered.

Top-level project directories with properties or comments make this command die (return status 1) with an error message on stderr; otherwise these directories are silently discarded.

Otherwise, swaps "trunk" and the top-level (project) directory straight up.  For tags and branches, the following two components are swapped to the top.  thus, "foo/branches/release23" becomes "branches/release23/foo", putting the project directory beneath the branch.

Also fires when an entire project directory is copied; this is transformed into a copy of trunk and copies of each subbranch and tag that exists.

After the swap, there are attempts to recognize spans of copies into branch directories, and copies into tag subdirectories that are parallel in all top-level (project) directories. These are coalesced into single copies in the inverted structure.  No attempts is made to coalesce deletes; the user must manually trim unneeded branches.

Accordingly, copies with three-segment sources and three-segment targets are transformed; for tags/ and branches/ paths the last segment (the subdirectory below the branch name) is dropped, Following copies are skipped.

This has two minor negative consequences. One is that metadata belonging to all deletes or copies after the first one in a coalesced span is lost.  The other is that branches and tags local to individual project directories are promoted to global branches and tags across the entire transformed repository; no content is lost this way.

Parallel rename sequences are also coalesced.

If a PATTERN argument is given, only paths matching the pattern are swapped.

Note that the result of swapping does not have initial trunk/branches/tags directory creations and can thus not be fed directly to svnload. reposurgeon copes with this, but Subversion will not.

Merfeinfo propertied are updated to use the swapped path names.

This transform can be restricted by a selection set.

swapcheck

List directory prefixes of anomalous paths that would confuse swapsvn. This includes any single-segment path other than trunk/tags/branches or a project copy operation, any path with two or more segments in which the second is not trunk/tags/branches, and any path in which trunk/tags/branches occurs more than one segment down from the root.

Each report line has two fields; the first is the earliest revision containing a path with the prefix given, and the second is the prefix.  Once a particular path prefix has been recognized and reported as anomalous, later paths with that prefix are not reported.

If feeding a Subversion dump to this subcommand doesn’t produce an empty report, you can expect swapsvn to produce an invalid dump that will confuse and possibly crash reposurgeon. The remedy for this is a set of pathrenames and/or deselections that yields paths conformable to being swapped into a regular Subversion structure.

replace

Perform a regular expression search/replace on blob content. The first character of the argument (normally /) is treated as the end delimiter for the regular-expression and replacement parts. This transform can be restricted by a selection set.

strip

Replace content with unique generated cookies on all node paths matching the specified regular expressions; if no expressions are given, match all paths.

This command is useful for reducing the bulk of a stream without touching its metadata, so you can do test conversions more quickly.

hash

Replace content with hash on all node paths matching the specified regular expressions; if no expressions are given, match all paths.

obscure

Replace path segments and committer IDs with arbitrary but consistent names in order to obscure them. The replacement algorithm is tuned to make the replacements readily distinguishable by eyeball.  This transform can be restricted by a selection set.

reduce

Strip revisions out of a dump so the only parts left those likely to be relevant to a conversion problem. This is done by dropping every node that consists of a change on a file and has no property settings. Mergeinfo properties in all revisions are updated so they no longer refer to dropped revisions.

testify

Replace commit timestamps with a monotonically increasing clock tick starting at the Unix epoch and advancing by 10 seconds per commit. Replace all attributions with 'fred'.  Discard the repository UUID. Use this to neutralize procedurally-generated streams so they can be compared. This transform can be restricted by a selection set.

count

Set the debug level to the specified value on the selected revisions. Setting debugging enables diagnostics to standard error, and suppresses the progress baton for the entire run in order not to step on any diagnostics that might be emitted.

For the meaning of the debug levels, see the source code.  This option is probably only of interest to repocutter developers.

version

Report major and minor repocutter version.

Under the name "svncutter", an ancestor of this program traveled in the 'contrib/' director of the Subversion distribution. It had functional overlap with reposurgeon(1) because it was directly ancestral to that code. It was moved to the reposurgeon(1) distribution in January 2016.  This program was ported from Python to Go in August 2018, at which time the obsolete "squash" command was retired.  The syntax of regular expressions in the pathrename command changed at that time.

The reason for the partial functional overlap between repocutter and reposurgeon is that repocutter was first written earlier and became a testbed for some of the design concepts in reposurgeon. After reposurgeon was written, the author learned that it could not naturally support some useful operations very specific to Subversion, and enhanced repocutter to do those.

Normally 0. Can be 1 if repocutter sees an ill-formed dump, or if the output stream contains any copyfrom references to missing revisions.

There is one regression since the Python version: repocutter no longer recognizes Macintosh-style line endings consisting of a carriage return only. This may be addressed in a future version.

reposurgeon(1).

Suppose you have a Subversion repository with the following semi-pathological structure:

Directory1/ (with unrelated content)
Directory2/ (with unrelated content)
TheDirIWantToMigrate/
                branches/
                               crazy-feature/
                                               UnrelatedApp1/
                                               TheAppIWantToMigrate/
                tags/
                               v1.001/
                                               UnrelatedApp1/
                                               UnrelatedApp2/
                                               TheAppIWantToMigrate/
                trunk/
                               UnrelatedApp1/
                               UnrelatedApp2/
                               TheAppIWantToMigrate/

You want to transform the dump file so that TheAppIWantToMigrate can be subject to a regular branchy lift. A way to dissect out the code of interest would be with the following series of filters applied:

repocutter expunge '^Directory1' '^Directory2'
repocutter pathrename '^TheDirIWantToMigrate/' ''
repocutter expunge '^branches/crazy-feature/UnrelatedApp1/
repocutter pathrename 'branches/crazy-feature/TheAppIWantToMigrate/' 'branches/crazy-feature/'
repocutter expunge '^tags/v1.001/UnrelatedApp1/'
repocutter expunge '^tags/v1.001/UnrelatedApp2/'
repocutter pathrename '^tags/v1.001/TheAppIWantToMigrate/' 'tags/v1.001/'
repocutter expunge '^trunk/UnrelatedApp1/'
repocutter expunge '^trunk/UnrelatedApp2/'
repocutter pathrename '^trunk/TheAppIWantToMigrate/' 'trunk/'

The sift and expunge operations can produce output dumps that are invalid.  The problem is copyfrom operations (Subversion branch and tag creations).  If an included revision includes a copyfrom reference to an excluded one, the reference target won’t be in the emitted dump; it won’t load correctly in Subversion, and while reposurgeon has fallback logic that backs down to the latest existing revision before the kissing one this expedient is fragile. The revision number in a copyfrom header pointing to a missing revision will be zero. Attempts to be clever about this won’t work; the problem is inherent in the data model of Subversion.

Eric S. Raymond esr@thyrsus.com. This tool is distributed with reposurgeon; see the project page.