Allow variable-prefixed include statements in mk2rbc

mk2rbc was already searching the whole android tree
for Makefiles, so allowing variable-prefixed include
statements doesn't affect performance on the file searching
front. On the generated code front, there's already a cap
of 150 potentially-included makefiles that prevents the
performance from getting too bad, and it can be lowered
if necessary.

Bug: 213508006
Test: go test
Change-Id: I3a4e81acb3d97bee08ac3dbe63052a274acf5793
diff --git a/mk2rbc/mk2rbc_test.go b/mk2rbc/mk2rbc_test.go
index c4f7da3..20f198a 100644
--- a/mk2rbc/mk2rbc_test.go
+++ b/mk2rbc/mk2rbc_test.go
@@ -1072,13 +1072,7 @@
   cfg = rblf.cfg(handle)
   g["MY_PATH"] = "foo"
   #RBC# include_top vendor/foo1
-  _entry = {
-    "vendor/foo1/cfg.mk": ("vendor/foo1/cfg", _cfg_init),
-  }.get("%s/cfg.mk" % g["MY_PATH"])
-  (_varmod, _varmod_init) = _entry if _entry else (None, None)
-  if not _varmod_init:
-    rblf.mkerror("product.mk", "Cannot find %s" % ("%s/cfg.mk" % g["MY_PATH"]))
-  rblf.inherit(handle, _varmod, _varmod_init)
+  rblf.inherit(handle, "vendor/foo1/cfg", _cfg_init)
 `,
 	},
 	{
@@ -1098,25 +1092,13 @@
   cfg = rblf.cfg(handle)
   g["MY_PATH"] = "foo"
   #RBC# include_top vendor/foo1
-  _entry = {
-    "vendor/foo1/cfg.mk": ("vendor/foo1/cfg", _cfg_init),
-  }.get("%s/cfg.mk" % g["MY_PATH"])
-  (_varmod, _varmod_init) = _entry if _entry else (None, None)
-  if not _varmod_init:
-    rblf.mkerror("product.mk", "Cannot find %s" % ("%s/cfg.mk" % g["MY_PATH"]))
-  rblf.inherit(handle, _varmod, _varmod_init)
+  rblf.inherit(handle, "vendor/foo1/cfg", _cfg_init)
   #RBC# include_top vendor/foo1
-  _entry = {
-    "vendor/foo1/cfg.mk": ("vendor/foo1/cfg", _cfg_init),
-  }.get("%s/cfg.mk" % g["MY_PATH"])
-  (_varmod, _varmod_init) = _entry if _entry else (None, None)
-  if not _varmod_init:
-    rblf.mkerror("product.mk", "Cannot find %s" % ("%s/cfg.mk" % g["MY_PATH"]))
-  rblf.inherit(handle, _varmod, _varmod_init)
+  rblf.inherit(handle, "vendor/foo1/cfg", _cfg_init)
 `,
 	},
 	{
-		desc:   "Dynamic inherit path that lacks necessary hint",
+		desc:   "Dynamic inherit path that lacks hint",
 		mkname: "product.mk",
 		in: `
 #RBC# include_top foo
@@ -1133,26 +1115,23 @@
 		expected: `#RBC# include_top foo
 load("//build/make/core:product_config.rbc", "rblf")
 load("//foo:font.star|init", _font_init = "init")
+load("//bar:font.star|init", _font1_init = "init")
 
 def init(g, handle):
   cfg = rblf.cfg(handle)
-  _entry = {
-    "foo/font.mk": ("foo/font", _font_init),
-  }.get("%s/font.mk" % g.get("MY_VAR", ""))
-  (_varmod, _varmod_init) = _entry if _entry else (None, None)
-  if not _varmod_init:
-    rblf.mkerror("product.mk", "Cannot find %s" % ("%s/font.mk" % g.get("MY_VAR", "")))
-  rblf.inherit(handle, _varmod, _varmod_init)
+  rblf.inherit(handle, "foo/font", _font_init)
   #RBC# include_top foo
   # There's some space and even this comment between the include_top and the inherit-product
+  rblf.inherit(handle, "foo/font", _font_init)
+  rblf.mkwarning("product.mk:11", "Including a path with a non-constant prefix, please convert this to a simple literal to generate cleaner starlark.")
   _entry = {
     "foo/font.mk": ("foo/font", _font_init),
+    "bar/font.mk": ("bar/font", _font1_init),
   }.get("%s/font.mk" % g.get("MY_VAR", ""))
   (_varmod, _varmod_init) = _entry if _entry else (None, None)
   if not _varmod_init:
     rblf.mkerror("product.mk", "Cannot find %s" % ("%s/font.mk" % g.get("MY_VAR", "")))
   rblf.inherit(handle, _varmod, _varmod_init)
-  rblf.mk2rbc_error("product.mk:11", "inherit-product/include statements must not be prefixed with a variable, or must include a #RBC# include_top comment beforehand giving a root directory to search.")
 `,
 	},
 	{