How to I install Ghostscript 9.21 with homebrew? - homebrew

Question

I'm stuck using Ghostscript 9.21 on my project, and homebrew is installing 9.55. How do I install 9.21? I tried brew install ghostscript#9.21 but the package doesn't have versioning.
I'd like to use https://github.com/Homebrew/homebrew-core/blob/f7092d9202dbfbd9ea0ae70064c59e796b81d5df/Formula/ghostscript.rb but when I brew install https://github.com/Homebrew/homebrew-core/blob/f7092d9202dbfbd9ea0ae70064c59e796b81d5df/Formula/ghostscript.rb I get:
/opt/homebrew/Homebrew/Library/Homebrew/formulary.rb:277:in `load_file': Invalid usage: Installation of ghostscript from a GitHub commit URL is unsupported! `brew extract ghostscript` to a stable tap on GitHub instead. (UsageError)
I haven't been able to figure out how to do it with brew extract as it says.

Answer 1

brew extract was broken, and a fix has been merged. Now you can extract the formula:
Create a Homebrew tap where the formula will be extracted to:
brew tap-new $USER/local-tap
Extract Ghostscript 9.21 to your tap:
brew extract --version=9.21 ghostscript $USER/local-tap
However, there are still some changes that must be made to fix the formula:
Set the HOMEBREW_EDITOR environment variable to your editor of choice. Mine is code
Run brew edit ghostscript#9.21
Delete revision 4 because this is a new formula.
The sha256 hashes of the patches are wrong, probably because a=patch adds the Git version at the bottom of the patch. Let's change a=patch to a=commitdiff_plain and blank out sha256 to get the new hashes later:
patch do
url "https://git.ghostscript.com/?p=ghostpdl.git;a=commitdiff_plain;h=4f83478c88"
sha256 ""
end
patch do
url "https://git.ghostscript.com/?p=ghostpdl.git;a=commitdiff_plain;h=04b37bbce1"
sha256 ""
end
patch do
url "https://git.ghostscript.com/?p=ghostpdl.git;a=commitdiff_plain;h=57f20719e1"
sha256 ""
end
Delete the devel block:
- devel do
- url "https://github.com/ArtifexSoftware/ghostpdl-downloads/releases/download/gs922rc2/ghostscript-9.22rc2.tar.gz"
- sha256 "1861c0cee1e005bd2712873e3058ee1c131c79819625fe479ebcef68e055648e"
- end
(devel was deprecated somewhat recently.)
Delete depends_on :x11 => :optional (assuming you don't need X11 support)
Also delete if build.without? "x11" like so:
- args << "--without-x" if build.without? "x11"
+ args << "--without-x"
(:x11 has been replaced by the libx11 formula.)
Now run brew install -s ghostscript#9.21 and you'll get the new sha256 hashes mentioned above:
$ brew install -s ghostscript#9.21
==> Downloading https://git.ghostscript.com/?p=ghostpdl.git;a=commitdiff_plain;h=4f83478c88
-#O#- # #
Warning: Cannot verify integrity of '86093339e3f806acdd14f4ba35d2748f1c31cd4f5008d39a4646e9036b5cb767--ghostpdl.git-4f83478c88.patch'.
For your reference, the checksum is:
sha256 "fa46ee96c9896a6feb0f23fd4276023477988c904da52e581efbc78c307eb435"
Finally, your formula should look like this.