feature request: generate into a zipfile for python?

[ckchow]

https://developers.google.com/protocol-buffers/docs/reference/python-generated#invocation

The default python plugin is able to generate code directly into a zipfile. It determines whether to do this by looking at the suffix of the output path (and if it sees a .zip, it assumes you want a zipped output). Could we add an option to the python plugin to support this behavior? I think currently the plugin makes all the output directories up to and including outputSubdir. So this behavior almost works without modification except at the last second it complains

<...>.zip: Is a directory

[voidzcy]

Looks we only need to not create a directory for the leaf of the path given by outputSubDir if it ends with .jar or .zip, and things will be working out of the box. outputSubDir maps to the --builtin_out in protoc invocations.

[cilki]

This works great the first time I run the task, but all subsequent runs fail because the plugin makes the output zip itself a source directory:

Caused by: org.gradle.api.InvalidUserDataException: Source directory '.../build/generated-proto/main/cpp.zip' is not a directory.
	at org.gradle.api.internal.file.DefaultSourceDirectorySet.getSourceTrees(DefaultSourceDirectorySet.java:273)
	at org.gradle.api.internal.file.DefaultSourceDirectorySet.getSrcDirTrees(DefaultSourceDirectorySet.java:256)
	at org.gradle.api.internal.file.DefaultSourceDirectorySet.getSrcDirs(DefaultSourceDirectorySet.java:114)
...

Any way to avoid creating a new source directory or maybe just remove it before the task runs?