tonic-build fails when service in/out objects are extern_path'd

[cthulhua]

Bug Report

Version

tonic 0.1.1

Platform

Darwin Dannys-Work-MacBook-Pro.local 18.7.0 Darwin Kernel Version 18.7.0: Tue Aug 20 16:57:14 PDT 2019; root:xnu-4903.271.2~2/RELEASE_X86_64 x86_64

Crates

tonic-build

Description

The replace_wellknown function in tonic-build/src/lib.rs fails when any objects referred to in service method definitions have been replaced (via tonic/prost's extern_path functionality). These paths are absolute paths and should not be replace with a relative path rooted at super.

This failure results in a build failure (panic during build.rs execution):

   Compiling my_application v0.1.0 (/Users/danny/tonic_extern_path/my_application)
error: failed to run custom build command for `my_application v0.1.0 (/Users/danny/tonic_extern_path/my_application)`

Caused by:
  process didn't exit successfully: `/Users/danny/tonic_extern_path/target/debug/build/my_application-807cb5f2cea6c0e3/build-script-build` (exit code: 101)
--- stderr
thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: Error("expected identifier")', /Users/danny/.cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/tonic-build-0.1.1/src/lib.rs:332:9
stack backtrace:
   0:        0x10b6f6135 - backtrace::backtrace::libunwind::trace::h2645f0921d177f94
                               at /Users/runner/.cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/backtrace-0.3.40/src/backtrace/libunwind.rs:88
   1:        0x10b6f6135 - backtrace::backtrace::trace_unsynchronized::h2d634d751cc39c09
                               at /Users/runner/.cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/backtrace-0.3.40/src/backtrace/mod.rs:66
   2:        0x10b6f6135 - std::sys_common::backtrace::_print_fmt::hbf6c15b03ac1eab6
                               at src/libstd/sys_common/backtrace.rs:77
   3:        0x10b6f6135 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h0e1e1d13ef39c2d8
                               at src/libstd/sys_common/backtrace.rs:59
   4:        0x10b712e6d - core::fmt::write::h1fc31e3d3e8cc0fb
                               at src/libcore/fmt/mod.rs:1052
   5:        0x10b6f31db - std::io::Write::write_fmt::hfa2e20b6b4a124b0
                               at src/libstd/io/mod.rs:1426
   6:        0x10b6f855a - std::sys_common::backtrace::_print::h589a150dbcdc1aa6
                               at src/libstd/sys_common/backtrace.rs:62
   7:        0x10b6f855a - std::sys_common::backtrace::print::h0a4ab12a7b4cb43a
                               at src/libstd/sys_common/backtrace.rs:49
   8:        0x10b6f855a - std::panicking::default_hook::{{closure}}::h3e9aecc37d191470
                               at src/libstd/panicking.rs:204
   9:        0x10b6f825a - std::panicking::default_hook::h80723c33c50f1398
                               at src/libstd/panicking.rs:224
  10:        0x10b6f8c9a - std::panicking::rust_panic_with_hook::h6b9654fdaf8aa8f2
                               at src/libstd/panicking.rs:476
  11:        0x10b6f8752 - rust_begin_unwind
                               at src/libstd/panicking.rs:380
  12:        0x10b7122bf - core::panicking::panic_fmt::h3216996c707890c3
                               at src/libcore/panicking.rs:85
  13:        0x10b712105 - core::option::expect_none_failed::h7164670b9c7e7202
                               at src/libcore/option.rs:1199
  14:        0x10b468fb4 - core::result::Result<T,E>::unwrap::h742815421e739a87
                               at /rustc/698fcd38fa9548e64a2092ff48c9d15ceb57d40c/src/libcore/result.rs:963
  15:        0x10b463946 - tonic_build::replace_wellknown::h0e195b786cbcb49f
                               at /Users/danny/.cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/tonic-build-0.1.1/src/lib.rs:332
  16:        0x10b4542c2 - tonic_build::client::generate_unary::h94345f34402983e9
                               at /Users/danny/.cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/tonic-build-0.1.1/src/client.rs:104
  17:        0x10b453e9c - tonic_build::client::generate_methods::h8537e877aab43f5f
                               at /Users/danny/.cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/tonic-build-0.1.1/src/client.rs:90
  18:        0x10b44e1e5 - tonic_build::client::generate::h02f17dc0bdb8042b
                               at /Users/danny/.cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/tonic-build-0.1.1/src/client.rs:9
  19:        0x10b46292f - <tonic_build::ServiceGenerator as prost_build::ServiceGenerator>::generate::hc92a32b4748ce54b
                               at /Users/danny/.cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/tonic-build-0.1.1/src/lib.rs:259
  20:        0x10b5ebac2 - prost_build::code_generator::CodeGenerator::push_service::{{closure}}::h52d5b08105d0fe2e
                               at /Users/danny/.cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/prost-build-0.6.1/src/code_generator.rs:676
  21:        0x10b62e9c4 - core::option::Option<T>::map::h68a992540e3f113b
                               at /rustc/698fcd38fa9548e64a2092ff48c9d15ceb57d40c/src/libcore/option.rs:450
  22:        0x10b5eaf6f - prost_build::code_generator::CodeGenerator::push_service::hb7ab3e997bce8594
                               at /Users/danny/.cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/prost-build-0.6.1/src/code_generator.rs:673
  23:        0x10b5e238f - prost_build::code_generator::CodeGenerator::generate::hf6d95ada164997aa
                               at /Users/danny/.cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/prost-build-0.6.1/src/code_generator.rs:103
  24:        0x10b63ae0f - prost_build::Config::generate::hb4f2ccd547f80360
                               at /Users/danny/.cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/prost-build-0.6.1/src/lib.rs:593
  25:        0x10b3e19df - prost_build::Config::compile_protos::h970129da4bfd3b2d
                               at /Users/danny/.cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/prost-build-0.6.1/src/lib.rs:552
  26:        0x10b3d9b43 - tonic_build::Builder::compile::h47d23e4abc40987d
                               at /Users/danny/.cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/tonic-build-0.1.1/src/lib.rs:167
  27:        0x10b421a32 - build_script_build::main::h7748d180a3d5dab2
                               at my_application/build.rs:2
  28:        0x10b403d46 - std::rt::lang_start::{{closure}}::h851e48dc34dc34e1
                               at /rustc/698fcd38fa9548e64a2092ff48c9d15ceb57d40c/src/libstd/rt.rs:67
  29:        0x10b6f8678 - std::rt::lang_start_internal::{{closure}}::hafd3c32b6306bd09
                               at src/libstd/rt.rs:52
  30:        0x10b6f8678 - std::panicking::try::do_call::h3d3fe791c338e3a4
                               at src/libstd/panicking.rs:305
  31:        0x10b6ff43b - __rust_maybe_catch_panic
                               at src/libpanic_unwind/lib.rs:86
  32:        0x10b6f903e - std::panicking::try::ha0910ebc7dfbfd90
                               at src/libstd/panicking.rs:281
  33:        0x10b6f903e - std::panic::catch_unwind::h5badc5d02ddc3558
                               at src/libstd/panic.rs:394
  34:        0x10b6f903e - std::rt::lang_start_internal::he9cd64fc2d39fad3
                               at src/libstd/rt.rs:51
  35:        0x10b403d22 - std::rt::lang_start::h645d221085e6c85b
                               at /rustc/698fcd38fa9548e64a2092ff48c9d15ceb57d40c/src/libstd/rt.rs:67
  36:        0x10b421b72 - build_script_build::main::h7748d180a3d5dab2

I've put my minimal repro at https://github.com/cthulhua/tonic_extern_path.

Note that in the Cargo.toml for the my_application I've added commented out references to https://github.com/cthulhua/tonic/tree/extern_path wherein I've fixed the issue by simply excluding absolute paths from being made relative