panic in buf generate with misconfigured plugin

[derekperkins]

I added a new plugin go-json_out from https://github.com/mitchellh/protoc-gen-go-json and got some panics running buf generate until I got the actual error Failure: could not find protoc plugin for name go-json_out on the third try. That's when I realized that I needed to remove the _out suffix, after which the generate worked perfectly. Not a big deal, but probably worth fixing so that the error gets emitted correctly on the first run. Maybe also accepting or at least suggesting removing _out if detected?

buf.gen.yaml

version: v1
managed:
  enabled: true
  go_package_prefix:
    default: go.nozzle.io
plugins:
  - name: go
    out: .
    opt: paths=source_relative
  - name: go-grpc
    out: .
    opt:
      - paths=source_relative
      - require_unimplemented_servers=false
  - name: go-json_out
    out: .
    opt:
      - paths=source_relative
      - enums_as_ints=false
      - emit_defaults=false
      - orig_name=false
      - allow_unknown=false

Run 1

panic: send on closed channel

goroutine 110 [running]:
github.com/bufbuild/buf/private/buf/bufgen.semaphore.Acquire(0xc000d8f3e0, {0x1a99d68, 0xc001d37a00})
	github.com/bufbuild/buf/private/buf/bufgen/generator.go:584 +0x7a
github.com/bufbuild/buf/private/buf/bufgen.(*generator).generateConcurrently.func1()
	github.com/bufbuild/buf/private/buf/bufgen/generator.go:227 +0xa6
golang.org/x/sync/errgroup.(*Group).Go.func1()
	golang.org/x/sync@v0.0.0-20210220032951-036812b2e83c/errgroup/errgroup.go:57 +0x67
created by golang.org/x/sync/errgroup.(*Group).Go
	golang.org/x/sync@v0.0.0-20210220032951-036812b2e83c/errgroup/errgroup.go:54 +0x92
panic: send on closed channel

goroutine 118 [running]:
github.com/bufbuild/buf/private/buf/bufgen.semaphore.Acquire(0xc000d8f3e0, {0x1a99d68, 0xc001d37a00})
	github.com/bufbuild/buf/private/buf/bufgen/generator.go:584 +0x7a
github.com/bufbuild/buf/private/buf/bufgen.(*generator).generateConcurrently.func1()
	github.com/bufbuild/buf/private/buf/bufgen/generator.go:227 +0xa6
golang.org/x/sync/errgroup.(*Group).Go.func1()
	golang.org/x/sync@v0.0.0-20210220032951-036812b2e83c/errgroup/errgroup.go:57 +0x67
created by golang.org/x/sync/errgroup.(*Group).Go
	golang.org/x/sync@v0.0.0-20210220032951-036812b2e83c/errgroup/errgroup.go:54 +0x92

Run 2

panic: send on closed channel

goroutine 93 [running]:
github.com/bufbuild/buf/private/buf/bufgen.semaphore.Acquire(0xc001b621e0, {0x1a99d68, 0xc002b7d640})
	github.com/bufbuild/buf/private/buf/bufgen/generator.go:584 +0x7a
github.com/bufbuild/buf/private/buf/bufgen.(*generator).generateConcurrently.func1()
	github.com/bufbuild/buf/private/buf/bufgen/generator.go:227 +0xa6
golang.org/x/sync/errgroup.(*Group).Go.func1()
	golang.org/x/sync@v0.0.0-20210220032951-036812b2e83c/errgroup/errgroup.go:57 +0x67
created by golang.org/x/sync/errgroup.(*Group).Go
	golang.org/x/sync@v0.0.0-20210220032951-036812b2e83c/errgroup/errgroup.go:54 +0x92
panic: send on closed channel

goroutine 116 [running]:
github.com/bufbuild/buf/private/buf/bufgen.semaphore.Acquire(0xc001b621e0, {0x1a99d68, 0xc002b7d640})
	github.com/bufbuild/buf/private/buf/bufgen/generator.go:584 +0x7a
github.com/bufbuild/buf/private/buf/bufgen.(*generator).generateConcurrently.func1()
	github.com/bufbuild/buf/private/buf/bufgen/generator.go:227 +0xa6
golang.org/x/sync/errgroup.(*Group).Go.func1()
	golang.org/x/sync@v0.0.0-20210220032951-036812b2e83c/errgroup/errgroup.go:57 +0x67
created by golang.org/x/sync/errgroup.(*Group).Go
	golang.org/x/sync@v0.0.0-20210220032951-036812b2e83c/errgroup/errgroup.go:54 +0x92
panic: send on closed channel

goroutine 124 [running]:
github.com/bufbuild/buf/private/buf/bufgen.semaphore.Acquire(0xc001b621e0, {0x1a99d68, 0xc002b7d640})
	github.com/bufbuild/buf/private/buf/bufgen/generator.go:584 +0x7a
github.com/bufbuild/buf/private/buf/bufgen.(*generator).generateConcurrently.func1()
	github.com/bufbuild/buf/private/buf/bufgen/generator.go:227 +0xa6
golang.org/x/sync/errgroup.(*Group).Go.func1()
	golang.org/x/sync@v0.0.0-20210220032951-036812b2e83c/errgroup/errgroup.go:57 +0x67
created by golang.org/x/sync/errgroup.(*Group).Go
	golang.org/x/sync@v0.0.0-20210220032951-036812b2e83c/errgroup/errgroup.go:54 +0x92
panic: send on closed channel

goroutine 97 [running]:
github.com/bufbuild/buf/private/buf/bufgen.semaphore.Acquire(0xc001b621e0, {0x1a99d68, 0xc002b7d640})
	github.com/bufbuild/buf/private/buf/bufgen/generator.go:584 +0x7a
github.com/bufbuild/buf/private/buf/bufgen.(*generator).generateConcurrently.func1()
	github.com/bufbuild/buf/private/buf/bufgen/generator.go:227 +0xa6
golang.org/x/sync/errgroup.(*Group).Go.func1()
	golang.org/x/sync@v0.0.0-20210220032951-036812b2e83c/errgroup/errgroup.go:57 +0x67
created by golang.org/x/sync/errgroup.(*Group).Go
	golang.org/x/sync@v0.0.0-20210220032951-036812b2e83c/errgroup/errgroup.go:54 +0x92

Run 3

Failure: could not find protoc plugin for name go-json_out

[johanbrandhorst]

Oops, yeah those are some terrible errors, we'll get that fixed, thanks!

[bufdev]

This is fixed and will go out in a release on Monday.

[bufdev]

This is fixed on v1.0.0-rc3.