opencensus dependency issue with Go 1.13

[vcabbage]

When using this library with Go 1.13 (currently in beta), the following error is presented:

go: github.com/Azure/go-autorest/autorest@v0.8.0 requires
        github.com/Azure/go-autorest/tracing@v0.4.0 requires
        contrib.go.opencensus.io/exporter/ocagent@v0.4.6 requires
        github.com/census-instrumentation/opencensus-proto@v0.1.0-0.20181214143942-ba49f56771b8: invalid pseudo-version: version before v0.1.0 would have negative patch number

The pseudo-version referenced in contrib.go.opencensus.io/exporter/ocagent@v0.4.6's go.mod is considered invalid, but Go 1.12 and earlier don't check for it.

contrib.go.opencensus.io/exporter/ocagent v0.4.7 does reference a valid version for github.com/census-instrumentation/opencensus-proto.

If the dependency has already been cached by Go 1.12 the error doesn't present itself. To reproduce you can clear your module cache or use the golang:1.13beta1 docker container.

docker run -it --rm golang:1.13beta1
mkdir /test && cd /test && go mod init test
cat << EOF > main.go
package main

import _ "github.com/Azure/go-autorest/autorest"

func main() {}
EOF
go run .

I'm currently working around this by using a replace:

replace contrib.go.opencensus.io/exporter/ocagent => contrib.go.opencensus.io/exporter/ocagent v0.4.7

[vcabbage]

For anyone who happens across this issue, a more conservative replace would be:

replace github.com/census-instrumentation/opencensus-proto v0.1.0-0.20181214143942-ba49f56771b8 => github.com/census-instrumentation/opencensus-proto v0.0.3-0.20181214143942-ba49f56771b8

Which only fixes up the specific incorrect pseudo-version instead of upgrading a dependency.

[bcmills]

Note that you could achieve an effect equivalent to the ocagent replacement more robustly with:

require contrib.go.opencensus.io/exporter/ocagent v0.4.7

replace github.com/census-instrumentation/opencensus-proto v0.1.0-0.20181214143942-ba49f56771b8 => github.com/census-instrumentation/opencensus-proto v0.0.3-0.20181214143942-ba49f56771b8

That way, your build won't break if some future go get or import adds a (transitive) dependency on a feature added in ocagent v0.5.0 or later.

[jhendrixMSFT]

The dependencies on the various opencensus modules have been moved to the opencensus module which is not included by default, making it pay-for-play (see the CHANGELOG for details). If you don't need/want these opencensus dependencies can you please move to the latest version of the autorest module (and any others you're consuming from this repo)?

[vcabbage]

@jhendrixMSFT Thank you! (btw, there's a small typo in CHANGELOG, should be import instead of include.)

[jhendrixMSFT]

Oops I'll fix that in my next change. This should now be fixed, please let me know if you have further problems.