Cross language dependency: py_binary() depends upon cc

JG

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Jul 18, 2018, 7:18:33 PM7/18/18

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Dear Bazel users,

a. Looks like, py_binary(..) supports easily py_library(..) rule variants. However, our expectations to use cc_custom_target_binary(…) as cc_binnary(…) rule variants under py_binary(..) dependency. Here, we are facing “does not have mandatory providers: 'py' error” consistently, some existing references inline:

bazel wiki: py_binary

https://github.com/bazelbuild/bazel/issues/4237

https://github.com/tensorflow/models/issues/831

https://groups.google.com/forum/#!topic/bazel-discuss/QrdrQpYiyCA

As alternative, does it makes sense to investigate into sh_binary, Attributes common to all build rules, dependencies, Build configurations, Make variables areas to navigate for any feasible Bazel solution, or this problem itself "By Design" Bazel features/limitations over Cross Language binary dependency support coverage ?

Any idea/hint would be very highly appreciated.

Thanks in advance!

Kind Regards,
JG

László Csomor

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Jul 19, 2018, 5:56:38 AM7/19/18

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Hi JG,

Unfortunately Bazel doesn't yet support py_* rules to depend on cc_* rules. There are no design limitations against it, but we haven't implemented this support yet.

The error message you see means that the interface that py_* binary rules expect from their dependencies (the "py" provider) is not implemented by the cc_* rule.

Geschäftsführer: Paul Manicle, Halimah DeLaine Prado

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Ulf Adams

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Jul 19, 2018, 6:03:38 AM7/19/18

to László Csomor, jg.i...@gmail.com, bazel-dev

As a workaround, you may be able to make the py_binary have a data dependency on the cc_binary and make the name of the cc_binary lib<name>.so to get it to build a dynamic library. I believe this is what others are doing. I would expect py_binary.deps -> cc_binary to continue to be illegal even when we implement py/cc interop.

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Marcel Hlopko

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Jul 19, 2018, 12:02:15 PM7/19/18

to Ulf Adams, László Csomor, Joyabrata Ghosh, bazel-dev

You'll have to also set linkshared = 1 on the cc_binary in order to make shared library.

I can imagine allowing py_library\py_binary to depend on cc_library. But that's also TBD, I'm not promising anything :)

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Marcel Hlopko | Software Engineer | hlo...@google.com |

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Cross language dependency: py_binary() depends upon cc_binary() rule feasible ?

JG

László Csomor

Ulf Adams

Marcel Hlopko