A RubyGems plugin for patching gems
Latest commit 073bbcf Jun 22, 2015 Josef Stribny Version should be 0.1.6



A RubyGems plugin that patches gems.


gem-patch is a RubyGems plugin that helps to patch gems without manually opening and rebuilding them. It opens a given .gem file, extracts it, patches it with system patch command, clones its spec, updates the file list and builds the patched gem.


Run gem install gem-patch and you are done.


On Fedora you can use YUM:

sudo yum install rubygem-gem-patch


gem patch [options] name-version.gem PATCH [PATCH ...]

Supported options

option alternative syntax description
-pNUMBER --strip-numberNUMBER Sets the file name strip count to NUMBER.
-FNUMBER --fuzz=NUMBER Set NUMBER of lines to ignore in looking for places to install a hunk.
-oFILE --output=FILE Set output FILE.
--patch-options=OPTIONS Pass additional patch command options.
-cPATHS --copy-in=PATHS Copy in files or folders (separated by comma)
-rPATHS --remove=PATHS Remove files or folders before rebuild (separated by comma)
--dry-run Print the results from patching, but do not change any files.
--verbose Print additional info and STDOUT from patch command.

For versions higher than 0.1.4 --dry-run switch behaviour has been changed and it's not the same as in original patch command. Instead, gem-patch lets patch command modify files, but doesn't override the gem to be patched nor the output file at the end. This way we can easily use dry run also for patches involving more diffs changing each other.

If you need to check patching files that are not part of .gem release (such as a separate test suite), you can do it with --copy-in=test,folders option. If you don't want to include those additional files then delete them with --remove=test,folders.


This version is build for both RubyGems 1.8 and RubyGems 2.0.


Released under the MIT license. Feel free to contribute!