1 files changed, 64 insertions, 0 deletions
diff --git a/vendor/go.opentelemetry.io/otel/trace/doc.go b/vendor/go.opentelemetry.io/otel/trace/doc.go
index ab0346f96..440f3d756 100644
--- a/vendor/go.opentelemetry.io/otel/trace/doc.go
+++ b/vendor/go.opentelemetry.io/otel/trace/doc.go
@@ -62,5 +62,69 @@ a default.
 		defer span.End()
 		// ...
 	}
+
+# API Implementations
+
+This package does not conform to the standard Go versioning policy; all of its
+interfaces may have methods added to them without a package major version bump.
+This non-standard API evolution could surprise an uninformed implementation
+author. They could unknowingly build their implementation in a way that would
+result in a runtime panic for their users that update to the new API.
+
+The API is designed to help inform an instrumentation author about this
+non-standard API evolution. It requires them to choose a default behavior for
+unimplemented interface methods. There are three behavior choices they can
+make:
+
+  - Compilation failure
+  - Panic
+  - Default to another implementation
+
+All interfaces in this API embed a corresponding interface from
+[go.opentelemetry.io/otel/trace/embedded]. If an author wants the default
+behavior of their implementations to be a compilation failure, signaling to
+their users they need to update to the latest version of that implementation,
+they need to embed the corresponding interface from
+[go.opentelemetry.io/otel/trace/embedded] in their implementation. For
+example,
+
+	import "go.opentelemetry.io/otel/trace/embedded"
+
+	type TracerProvider struct {
+		embedded.TracerProvider
+		// ...
+	}
+
+If an author wants the default behavior of their implementations to panic, they
+can embed the API interface directly.
+
+	import "go.opentelemetry.io/otel/trace"
+
+	type TracerProvider struct {
+		trace.TracerProvider
+		// ...
+	}
+
+This option is not recommended. It will lead to publishing packages that
+contain runtime panics when users update to newer versions of
+[go.opentelemetry.io/otel/trace], which may be done with a trasitive
+dependency.
+
+Finally, an author can embed another implementation in theirs. The embedded
+implementation will be used for methods not defined by the author. For example,
+an author who wants to default to silently dropping the call can use
+[go.opentelemetry.io/otel/trace/noop]:
+
+	import "go.opentelemetry.io/otel/trace/noop"
+
+	type TracerProvider struct {
+		noop.TracerProvider
+		// ...
+	}
+
+It is strongly recommended that authors only embed
+[go.opentelemetry.io/otel/trace/noop] if they choose this default behavior.
+That implementation is the only one OpenTelemetry authors can guarantee will
+fully implement all the API interfaces when a user updates their API.
 */
 package trace // import "go.opentelemetry.io/otel/trace"