Support modern location expansions for run_binary

rules/run_binary.bzl

@@ -20,6 +20,22 @@ Runs a binary as a build action. This rule does not require Bash (unlike native.
 
 load("//lib:dicts.bzl", "dicts")
 
+_NOOPS = ("$(rlocationpath", "$(rootpath")
+_EXPANDS = ("$(execpath", "$(location")
+
+def _is_expandable(value):
+    for noop in _NOOPS:
+        if noop in value:
+            # buildifier: disable=print
+            print("The `{}` expansion value is unused by `run_binary`. It's use will not be expanded.".format(
+                noop,
+            ))
+    for prefix in _EXPANDS:
+        if prefix in value:
+            return True
+
+    return False
+
 def _impl(ctx):
     tool_as_list = [ctx.attr.tool]
     args = [
@@ -33,12 +49,12 @@ def _impl(ctx):
         # tokenization they would have to write args=["'a b'"] or args=["a\\ b"]. There's no
         # documented tokenization function anyway (as of 2019-05-21 ctx.tokenize exists but is
         # undocumented, see https://github.com/bazelbuild/bazel/issues/8389).
-        ctx.expand_location(a, tool_as_list) if "$(location" in a else a
+        ctx.expand_location(a, tool_as_list) if _is_expandable("$(location") else a
         for a in ctx.attr.args
     ]
     envs = {
         # Expand $(location) / $(locations) in the values.
-        k: ctx.expand_location(v, tool_as_list) if "$(location" in v else v
+        k: ctx.expand_location(v, tool_as_list) if _is_expandable(v) else v
         for k, v in ctx.attr.env.items()
     }
     ctx.actions.run(