Recent merge broke downstream projects

[orlangure]

#1071 which was supposed to fix downstream broke it again:

../../../contrib.go.opencensus.io/exporter/ocagent/transform_stats_to_metrics.go:257:5: 
cannot use exmplr.Attachments (type metricdata.Attachments) as type map[string]string in field value

It continues the story of breaking downstream by #1067 and fixing it by census-ecosystem/opencensus-go-exporter-ocagent#49.

@songy23 @rghetia

[orlangure]

Fixed by census-ecosystem/opencensus-go-exporter-ocagent#53

[songy23]

Apologies I forgot to mention if you're using Go modules, this kind of issues can be avoided by using a released version in go.mod:

require (
	contrib.go.opencensus.io/exporter/ocagent v0.4.7
	go.opencensus.io v0.19.2
        ...
)

Generally speaking we use master as a dev branch instead of a release branch.

[orlangure]

@songy23, unfortunately in our case this package is not our direct dependency, so we can't actually lock it down.

[songy23]

I see, thanks for the explanation. Assume it's Azure Go SDK, I saw there's an issue on supporting Go modules in Azure/azure-sdk-for-go#2993, hopefully it can help with the dependency issues once it's added.

[ZacJoffe]

Can confirm that v0.4.8 doesn't work with the Azure Autorest, and using v0.4.7 in our go.mod file works.

@songy23 may I ask why you use master as a dev branch?

[songy23]

Kind of a convention - we've been used to using master for dev, and creating separate release branches or tags for release. @rghetia mentioned we could consider using a dedicated dev branch for development and use master for releases instead, though I'm not sure if that's the best practice in Go.

[rghetia]

once go module is adopted this should not be a problem.

Switching to dev branch will not solve the problem as you can still bring the breaking change from dev to master.

[ZacJoffe]

We use Go modules with our codebase, and yes theoretically it shouldn't be an issue as long as the dependency was added when a stable build was checked in. If you were to import the Azure Autorest package today, however, it wouldn't work due to a broken master branch.

While @rghetia is right, the code deployed this morning to the exporter doesn't even compile.