This repository contains a minimal example of a problem between ts_library and rollup_bundle i've been having.
Setup
lib contains a minimal typescript library in its src directory and has a BUILD.bazel file mapping the src folder as module_root under module_name kevin.
lib_root contains the same library as lib but not inside of a src folder.
app contains a minimal rollup.config.js and a index.ts file using the kevin function from the kevin library with a bundle target in its BUILD.bazel file that runs the rollup_bundle step.
Problems
when building the bundle in the current configuration the ts_library step completes successfully but during bundling the kevin library cannot be found while the kevin_root library resolves successfully.
Moving the index.ts file to the root of the lib package and updating the BUILD.bazel file to reflect those changes allows for proper compilation, which leads me to suspect some problem in the module_root mapping.