Transitive dependencies in Go

This repository was an experiment to learn better how transitive dependencies work in Go. It contains two Go modules:

• A library module that houses two packages. One of these packages cgo has a dependency on the Confluent Kafka client, which requires CGO_ENABLED to build. The other package clean is standard Go.
• An application module that has a dependency on the library module. This application requires the library as a whole but only imports the standard Go package in its source code.

Notice that the application does not state any transitive dependency on the Confluent Kafka client in its go.mod. You can build the application successfully without CGO_ENABLED=1 using the Makefile target.

Use make cgo to switch the application code so that it now imports the cgo package from the library. Then run go mod tidy. You will now be able to see the Confluent client in the go.mod as an indirect dependency. You will also be unable to build main.go unless you have CGO_ENBALED=1.