String; nonconfigurable; default is None
An explanatory warning message associated with this target. Typically this is used to notify users that a target has become obsolete, or has become superseded by another rule, is private to a package, or is perhaps considered harmful for some reason. It is a good idea to include some reference (like a webpage, a bug number or example migration CLs) so that one can easily find out what changes are required to avoid the message. If there is a new target that can be used as a drop in replacement, it is a good idea to just migrate all users of the old target.
This attribute has no effect on the way things are built, but it
may affect a build tool's diagnostic output. The build tool issues a
warning when a rule with a deprecation
attribute is
depended upon by a target in another package.
Intra-package dependencies are exempt from this warning, so that, for example, building the tests of a deprecated rule does not encounter a warning.
If a deprecated target depends on another deprecated target, no warning message is issued.
Once people have stopped using it, the target can be removed.