Move runfiles from DefaultInfo into FilesToRun

ctx.actions.run(tools=[...]) may take instances of FilesToRun.
FilesToRun should therefore be complete enough that it describes an
executable and all of its runtime dependencies. We should therefore
place the runfiles not in DefaultInfo, but in FilesToRun.

Author: EdSchouten

starlark/builtins_core/exports.bzl

@@ -91,29 +91,34 @@ _runfiles = runfiles
 
 def _default_info_init(*, data_runfiles = None, default_runfiles = None, executable = None, files = None, runfiles = None):
     return {
-        # Bazel documents DefaultInfo(data_runfiles, default_runfiles)
-        # and DefaultInfo.data_runfiles as features to avoid. The
-        # distinction between "data" and "default" runfiles is only
-        # maintained for legacy reasons. Keep this implementation simple
-        # by only storing a single copy of the runfiles.
-        "default_runfiles": (runfiles or _runfiles()).merge_all(
-            ([default_runfiles] if default_runfiles else []) +
-            ([data_runfiles] if data_runfiles else []),
-        ),
         "files": files or depset(),
         "files_to_run": FilesToRunProvider(
+            # According to the Bazel documentation, only the runfiles
+            # parameter should be used. Calling DefaultInfo() with
+            # data_runfiles or default_runfiles is deprecated. In this
+            # implementation we simply merge all of the runfiles
+            # together.
+            _runfiles = (runfiles or _runfiles()).merge_all(
+                ([data_runfiles] if data_runfiles else []) +
+                ([default_runfiles] if default_runfiles else []),
+            ),
             executable = executable,
             repo_mapping_manifest = None,
             runfiles_manifest = None,
         ),
     }
 
-def _default_info_data_runfiles(r):
-    return r.default_runfiles
+def _default_info_runfiles(r):
+    # There is no point in storing the runfiles both in DefaultInfo and
+    # the FilesToRunProvider contained within. Simply let
+    # DefaultInfo.{data,default}_runfiles return the runfiles object
+    # contained in the FilesToRunProvider.
+    return r.files_to_run._runfiles
 
 DefaultInfo, _DefaultInfoRaw = provider(
     computed_fields = {
-        "data_runfiles": _default_info_data_runfiles,
+        "data_runfiles": _default_info_runfiles,
+        "default_runfiles": _default_info_runfiles,
     },
     init = _default_info_init,
 )