Check the exact full import name for eager imports

Summary: We used to check parent import and `fromlist` separately for eagerness. This makes it so we check for the exact full import name on the container instead. This works well with the strategy files introduced in D65434680 and D65555319.

Reviewed By: brittanyrey

Differential Revision: D65216354

fbshipit-source-id: 3e6972444a370ca981324256904e5d94bc77af4f

Python/import.c

@@ -1637,25 +1637,18 @@ add_lazy_modules(PyThreadState *tstate, PyObject *builtins, PyObject *name, PyOb
     PyObject *lazy_submodules;
 
     if (tstate->interp->eager_imports != NULL) {
-        int found = PySequence_Contains(tstate->interp->eager_imports, name);
-        if (found < 0) {
-            goto error;
-        }
-        if (found) {
-            ret = 0; /* If the module is flagged as eager import, load eagerly */
-            goto end;
-        }
+        Py_ssize_t size = 0;
         if (fromlist != NULL && fromlist != Py_None) {
             assert(PyTuple_CheckExact(fromlist));
-            Py_ssize_t size = PyTuple_GET_SIZE(fromlist);
+            size = PyTuple_GET_SIZE(fromlist);
             for (Py_ssize_t i = 0; i < size; ++i) {
                 PyObject* item = PyTuple_GET_ITEM(fromlist, i);
                 assert(PyUnicode_Check(item));
                 PyObject *from_name = PyUnicode_FromFormat("%U.%U", name, item);
                 if (from_name == NULL) {
                     goto error;
                 }
-                found = PySequence_Contains(tstate->interp->eager_imports, from_name);
+                int found = PySequence_Contains(tstate->interp->eager_imports, from_name);
                 Py_DECREF(from_name);
                 if (found < 0) {
                     goto error;
@@ -1666,6 +1659,16 @@ add_lazy_modules(PyThreadState *tstate, PyObject *builtins, PyObject *name, PyOb
                 }
             }
         }
+        if (size == 0) {
+            int found = PySequence_Contains(tstate->interp->eager_imports, name);
+            if (found < 0) {
+                goto error;
+            }
+            if (found) {
+                ret = 0; /* If the module is flagged as eager import, load eagerly */
+                goto end;
+            }
+        }
     }
 
     lazy_submodules = PyDict_GetItemWithError(lazy_modules, name);