bazel_module_tags

Contains the tags in a module for the module extension currently being processed. This object has a field for each tag class of the extension, and the value of the field is a list containing an object for each tag instance. This "tag instance" object in turn has a field for each attribute of the tag class.

Tag instance objects have a _sort_key field that returns an opaque value that can be compared with other sort keys to determine the relative order of tags, even across tag classes. Tags are ordered by their position within a module file and by the BFS ordering of modules in the dependency graph. This can be used with sorted() to recover the original order of tags: sorted(tags, key=lambda tag: tag._sort_key).

When passed as positional arguments to print() or fail(), tag instance objects turn into a meaningful string representation of the form "'install' tag at /home/user/workspace/MODULE.bazel:3:4". This can be used to construct error messages that point to the location of the tag in the module file, e.g. fail("Conflict between", tag1, "and", tag2).