Stream types

In the stream spec, you assign stream types in a stream hierarchy The set of parent-to-child relationships between streams in a stream depot. according to the stream’s expected usage, stability, and flow of change:

Type	Description
Development	code that changes frequently experiment without destabilizing the mainline stream
Mainline	code that changes somewhat frequently, but is more stable than code in development streams it is common to implement new features in the mainline
Release	the most stable code and the closest to being released enables you to put existing features in the final state
Task	lightweight short-lived streams see Task streams
Virtual	filtered view of a stream see Virtual streams

Merge down, copy up

A release stream is more stable than its mainline stream parent.

A development stream is less stable than its mainline stream parent.

Merging incorporates another stream’s changes into your stream, and can require you to resolve conflicts.

Copying duplicates the source stream to the target. Changes are merged down (to streams of lesser stability) and copied up (to streams of greater stability).

Stream types - most stable to least stable

Stream Type	Stability	Merge	Copy
release	Highly stable	to parent	from parent
mainline	Stable per your policy (for example, all code builds)	from child (from release, or to development)	to child (to release, or from development)
development	Unstable	from parent	to parent
task	Unstable	from parent	to parent
virtual	N/A; used to filter streams	N/A	N/A