Building a single bottle for all platforms

[Idane]

Output of brew config

Irrelevant

Output of brew doctor

Irrelevant

Description of issue

Hi, I intend to distribute a jar with brew. The jar is identical for all platforms. I set up a tap here: https://github.com/krud-dev/homebrew-tap and used the default actions to generate the bottles. While experimenting I found that a bottle tagged with 'all' will work for all platforms.

My question is, how can I instruct test-bot to generate the bottle artifact as "all" rather than "x86_64_linux"?

[SMillerDev]

If it detects that the hashes for all platforms are the same it'll make it an all bottle.

[SMillerDev]

I'd recommend just testing the compatibility on both platforms and let brew calculate the bottle type. I don't know of any way to force it.

[Idane]

Problem with jar files is that the hash will be different every time, so that won't solve it. Would you be open to a PR to add a flag to override this behaviour and force all?

[SMillerDev]

That seems like it won't be the same between OS versions then if it's not the same between runs, especially since Homebrew packages a bunch of jar files that do not have this issue.

[Idane]

I'm unsure of the difference between myself and these jars.
In any case, here is a simple project outlining this issue and showing that an identical build can produce two different hashes. I wrote a script that builds the same project in isolation twice, and prints out the hashes. You can take a look at the output here under Build and Analyze

First hash:  08b90f0a02fff853a9253a45873c6f681e67924811fdc8c45e9102f655b919ba build/first/libs/buildtestjava-1.0-SNAPSHOT.jar
Second hash:  7e55431714c83e236c3086724a44cf37bed63495f5ad477849d957f2676c97dc build/second/libs/buildtestjava-1.0-SNAPSHOT.jar

[gromgit]

It's been a while since I last Java'd, but if your JARs are anything like typical Java runtime ones, then it's either the manifest file that's different across platforms:

ubuntu$ unzip -p /usr/share/java/gettext.jar META-INF/MANIFEST.MF
Manifest-Version: 1.0
Created-By: 11.0.16 (Ubuntu)

or the order of files in the JAR, or their file timestamps.

In particular, zipping up a class hierarchy recursively is not guaranteed to package individual classes in the same order on the same platform each time, much less on different platforms. This of course would definitely affect the hash of the overall JAR, even if all the contents were identical.