dpatch - Online in the Cloud

PROGRAM:

NAME

dpatch - patch maintenance system for Debian

SYNOPSIS

dpatch [options] command [command-arguments]

DESCRIPTION

dpatch is an easy to use patch system for Debian packages, somewhat similar to the dbs
package, but much simpler to use.

It lets you store patches and other simple customization templates in debian/patches and
otherwise does not require much reorganization of your source tree. To get the patches
applied at build time you simply need to include a makefile snippet and then depend on the
patch/unpatch target in the build or clean stage of debian/rules. For added flexibility,
you can call /usr/bin/dpatch directly too.

WARNING

dpatch is deprecated, please switch to the `3.0 (quilt)' Debian source package format
instead. See http://wiki.debian.org/Projects/DebSrc3.0#FAQ for a short guide on how to do
it.

GLOBAL OPTIONS

There are a few options which change the overall behaviour of dpatch, and have an effect
on not only one, but most of the available commands.

These global options are:

--workdir (-d) DIRECTORY
By default, dpatch applies patches to the source tree it was run from. With this
option, one can change that, and tell dpatch to work on a different tree, although
taking the dpatches from the current one.

Note that this will only pass a second argument to dpatch scriptlets, and will not
change to the specified directory. To do that, use the --chdir option explained
below.

--chdir (-c)
When using a different working directory than the current one, change there before
trying to apply patches.

This should be used together with the --workdir option.

--strict (-S)
Enable strict mode, which means that dpatch will bail out early even on warnings
(like when trying to apply a patch which is already applied - normally it will
simply skip it).

--force (-F)
Force the application or deapplication of patches, even if dpatch would normally
skip them because the operation was already done earlier.

--with-cpp
Force the use of cpp. Overrides use of DPATCH_OPTION_CPP=1 option in
debian/patches/00options file.

COMMANDS

Patch handling commands
There is a generic syntax for all patch handling commands, namely that, that the command
itself takes a list of dpatch names to work with, then does what it is meant to do on all
of them, in the exact same order it was specified on the command line.

Then, there is a version of each patch handling command with an -all suffix, which does
not take any arguments, and performs the necessary action for each and every available
dpatch.

The last variation is a command with a -until or -up-to suffix, which takes only one
argument: the name of a dpatch. The appropriate action will be performed on all dpatches
up to and including this specified one.

apply [options]
patch [options]
Applies one or more dpatches to the working tree (the current directory, if not
told otherwise). By default the specified patches will be applied in the exact same
order they were specified.

Options
--stampdir=directory, -s=directory
Put stamp files into directory instead of the default debian/patched.
--help (-h)
Print a short help message about the command.
--quiet (-q)
Forces the command to not print anything.
--verbose (-v)
Disables hiding of the scriptlet output.

deapply [options]
unpatch [options]
Deapplies one or more dpatches to the working tree (the current directory, if not
told otherwise). By default the specified patches will be deapplied in the reverse
order they were specified as one generally should deapply in reverse order
(compared to the apply order, that is).

Options
--stampdir=directory, -s=directory
Use stamp files in directory instead of the default debian/patched.
--help (-h)
Print a short help message about the command.
--quiet (-q)
Forces the command to not print anything.
--verbose (-v)
Disables hiding of the scriptlet output.

cat [options]
Print meta-information about a dpatch, such as its name, author and description
(any of which can be disabled with the appropriate option).

Options
--no-meta, --desc-only (-nm, -d)
Only print the patch description.
--author-only (-a)
Only print the author of the patch.
--no-desc, (-nd)
Do not print the patch description.
--help (-h)
Print a short help message about the command.
--quiet (-q)
Forces the command to not print anything.

list [options]
List the name of the given patches. This commands is not really useful, except the
list-all variant, which lists all available patches.

Options
--help (-h)
Print a short help message about the command.

status [options]
Prints the status of the given patches - whether they are applied to the working
tree or not.

Options
--stampdir=directory, -s=directory
Use stamp files in directory instead of the default debian/patched.
--help (-h)
Print a short help message about the command.
--quiet (-q)
Forces the command to not print anything.

log [options]
Displays the log of the given patching attempts.

Options
--stampdir=directory, -s=directory
Use stamp files in directory instead of the default debian/patched.
--help (-h)
Print a short help message about the command.
--quiet (-q)
Forces the command to not print anything, but the logs without extra
sugar on top.

call [options]
Call a dpatch with a user-specified argument. All arguments with a pkg- prefix is
guaranteed to be unused by dpatch itself, and are reserved for use with this very
command.

This command is most useful for extracting custom meta-information from dpatch
scriptlets.

Options
--argument=arg (-a=arg)
Call patches with arg as argument.
--help (-h)
Print a short help message about the command.
--quiet (-q)
Forces the command to not print anything.

Miscellaneous commands
patch-template [options] [patchname] [description]
Print a quasi-standard dpatch script template, based on the information give on the
command-line. If a description given, it will be folded at about 72 characters into
multiple lines appropriately.

When prepending the template to STDIN, the contents of the standard input will be
printed right after the template.

Options
--prepend (-p)
Prepend the template to STDIN.
--help (-h)
Print a short help message about the command.

help (--help, -h) [command]
Attempt to give a little more detailed help about dpatch itself, or about a given
dpatch command.

version
Prints the dpatch version number and exits.

DPATCH IN DEBIAN PACKAGES

There are two different ways to use dpatch in debian/rules: calling it directly, or
including dpatch.make(7). Only the former method will be described here - the latter has
its own manual page.

NOTE: The following examples also require adding the .NOTPARALLEL flag to the head of
debian/rules since the dependency lists rely on the order of the execution. Without
.NOTPARALLEL, they execution order may be wrong with multiple make threads (the -j
option).

In most situations, one will want to run dpatch as soon during the build process, as
possible. How that can be accomplished depends heavily on the existing debian/rules.
However, in common practice most packages have a build (or build-stamp), config.status, or
configure (or configure-stamp) target. The easiest way to make dpatching the very first
thing, one only has to write a rule that calls dpatch, and add it to the list of
prerequisites for the appropriate target (see above).

Deapplying dpatches can be easy or a bit more tricky. If nothing in the clean rule touches
files modified by dpatches (creating incompatible changes), you can safely add unpatch to
the list of the clean rules dependencies.

If the patches might affect the build system, they should be deapplied after the source
tree has been cleaned. To do this, rename the clean target to, say, clean-patched, write a
rule that calls dpatch to deapply the dpatches, and make a new clean rule that has
clean-patched and unpatch as its prerequisites.

Let us look at an example! First, let us look at the relevant parts of the original
debian/rules of our imaginary package:

config.status: configure
./configure --prefix=/usr --mandir=/usr/share
build: config.status
${MAKE}
clean:
$(testdir)
$(testroot)
${MAKE} distclean
rm -rf debian/imaginary-package debian/files debian/substvars

After dpatchifying, this would look like this:

config.status: patch configure
./configure --prefix=/usr --mandir=/usr/share
build: config.status
${MAKE}
clean: clean-patched unpatch
clean-patched:
$(testdir)
$(testroot)
${MAKE} distclean
rm -rf debian/imaginary-package debian/files debian/substvars

patch: patch-stamp
patch-stamp:
dpatch apply-all
dpatch cat-all >patch-stamp

unpatch:
dpatch deapply-all
rm -rf patch-stamp debian/patched

Adding dpatch scriptlets to a package
When using dpatch, one surely wants to tell the system what dpatches to apply, and which
ones to discard. In the most common situation, one only needs to list the names of the
dpatches (the filenames relative to debian/patches) in debian/patches/00list. They
usually have the extension .dpatch and the extension can be omitted, thus a file
debian/patches/01_one_patch.dpatch is written as 01_one_patch inside debian/patches/00list

However, there may be situations where something more flexible is needed, like applying
the same patch on only two architectures, say, m68k and powerpc. One solve this in at
least two very different ways: One is to list the same patch in both
debian/patches/00list.m68k and debian/patches/00list.powerpc, the other is to use
DPATCH_OPTION_CPP=1 in debian/patches/00options. 00list file is passed through cpp
command with DEB_BUILD_ARCH variable set to the architecture, and
DEB_BUILD_ARCH_architecture being set to 1. With cpp, our sample debian/patches/00list
might look like this:

01_manpage_typo
#if defined(DEB_BUILD_ARCH_m68k) || defined(DEB_BUILD_ARCH_powerpc)
/* This patch fixes a random build-time breakage on Macintosh boxen. */
02_macintosh_foo
#endif

Creating dpatch scriptlets
There are many ways to create dpatch scriptlets. They are simple, executable files, which
follow a standardised calling convention (documented in dpatch(7)).

You can fire up your $EDITOR, or use dpatch-edit-patch, and you should be all set.

For most cases, where the dpatch file is only to apply a simple patch, there is an even
easier way:

dpatch patch-template -p "01_some_patch" "A random patch" \
<random.diff >debian/patches/01_some_patch.dpatch

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