Don't allow __lazy_imports__ to work in try/except

Author: DinoV

Lib/test/test_import/__init__.py

@@ -2630,6 +2630,22 @@ def test_compatibility_mode_used(self):
 
         self.assertTrue("test.test_import.data.lazy_imports.basic2" in sys.modules)
 
+    def test_compatibility_mode_func(self):
+        try:
+            import test.test_import.data.lazy_imports.compatibility_mode_func
+        except ImportError as e:
+            self.fail('lazy import failed')
+
+        self.assertTrue("test.test_import.data.lazy_imports.basic2" in sys.modules)
+
+    def test_compatibility_mode_try_except(self):
+        try:
+            import test.test_import.data.lazy_imports.compatibility_mode_try_except
+        except ImportError as e:
+            self.fail('lazy import failed')
+
+        self.assertTrue("test.test_import.data.lazy_imports.basic2" in sys.modules)
+
     def test_compatibility_mode_relative(self):
         try:
             import test.test_import.data.lazy_imports.basic_compatibility_mode_relative

Lib/test/test_import/data/lazy_imports/basic_compatibility_mode_used.py

@@ -0,0 +1,3 @@
+__lazy_modules__ = ['test.test_import.data.lazy_imports.basic2']
+import test.test_import.data.lazy_imports.basic2
+test.test_import.data.lazy_imports.basic2.f()

Lib/test/test_import/data/lazy_imports/compatibility_mode_func.py

@@ -0,0 +1,5 @@
+__lazy_modules__ = ['test.test_import.data.lazy_imports.basic2']
+def f():
+    import test.test_import.data.lazy_imports.basic2
+
+f()

Lib/test/test_import/data/lazy_imports/compatibility_mode_try_except.py

@@ -0,0 +1,5 @@
+__lazy_modules__ = ['test.test_import.data.lazy_imports.basic2']
+try:
+    import test.test_import.data.lazy_imports.basic2
+except:
+    pass

Python/ceval.c

@@ -2986,81 +2986,10 @@ _PyEval_SliceIndexNotNone(PyObject *v, Py_ssize_t *pi)
     return 1;
 }
 
-int
-check_lazy_import_comatibility(PyThreadState *tstate, PyObject *lazy_modules,
-                               PyObject *builtins, PyObject *globals, PyObject *locals,
-                               PyObject *name, PyObject *fromlist, PyObject *level,
-                               PyObject **mod)
-{
-    int ilevel = PyLong_AsInt(level);
-    if (ilevel == -1 && _PyErr_Occurred(tstate)) {
-        return -1;
-    }
-
-    PyObject *abs_name = _PyImport_GetAbsName(tstate, name, globals, ilevel);
-    if (abs_name == NULL) {
-        return -1;
-    }
-
-    int contains = PySequence_Contains(lazy_modules, abs_name);
-    Py_DECREF(abs_name);
-    if (contains < 0) {
-        return -1;
-    } else if (contains == 0) {
-        *mod = NULL;
-        return 0;
-    }
-
-    _PyInterpreterFrame *frame = _PyEval_GetFrame();
-    if (frame == NULL) {
-        PyErr_SetString(PyExc_RuntimeError, "no current frame");
-        return -1;
-    }
-
-    PyObject *import_func;
-    if (PyMapping_GetOptionalItem(frame->f_builtins, &_Py_ID(__import__), &import_func) < 0) {
-        return -1;
-    }
-
-    if (import_func == NULL) {
-        _PyErr_SetString(tstate, PyExc_ImportError, "__import__ not found");
-        return -1;
-    }
-
-    PyObject *final_mod = _PyImport_LazyImportModuleLevelObject(tstate, name, import_func, globals,
-                                                        locals, fromlist, ilevel);
-    Py_DECREF(import_func);
-    if (final_mod == NULL) {
-        return -1;
-    }
-    *mod = final_mod;
-    return 0;
-}
-
 PyObject *
 _PyEval_ImportName(PyThreadState *tstate, PyObject *builtins, PyObject *globals, PyObject *locals,
             PyObject *name, PyObject *fromlist, PyObject *level)
 {
-    // Check if this module should be imported lazily due to the compatbility mode support via
-    // __lazy_modules__.
-    PyObject *lazy_modules;
-    if (globals != NULL &&
-        PyMapping_GetOptionalItem(globals, &_Py_ID(__lazy_modules__), &lazy_modules) < 0) {
-        return NULL;
-    }
-
-    PyObject *res;
-    if (lazy_modules != NULL) {
-        int lazy = check_lazy_import_comatibility(tstate, lazy_modules, builtins, globals,
-                                                  locals, name, fromlist, level, &res);
-        Py_DECREF(lazy_modules);
-        if (lazy < 0) {
-            return NULL;
-        } else if (res != NULL) {
-            return res;
-        }
-    }
-
     PyObject *import_func;
     if (PyMapping_GetOptionalItem(builtins, &_Py_ID(__import__), &import_func) < 0) {
         return NULL;
@@ -3070,7 +2999,7 @@ _PyEval_ImportName(PyThreadState *tstate, PyObject *builtins, PyObject *globals,
         return NULL;
     }
 
-    res = _PyEval_ImportNameWithImport(tstate, import_func, globals, locals, name, fromlist, level);
+    PyObject *res = _PyEval_ImportNameWithImport(tstate, import_func, globals, locals, name, fromlist, level);
     Py_DECREF(import_func);
     return res;
 }
@@ -3102,10 +3031,37 @@ _PyEval_ImportNameWithImport(PyThreadState *tstate, PyObject *import_func, PyObj
     return res;
 }
 
+int
+check_lazy_import_comatibility(PyThreadState *tstate, PyObject *globals,
+                               PyObject *name, PyObject *level)
+{
+     // Check if this module should be imported lazily due to the compatbility mode support via
+    // __lazy_modules__.
+    PyObject *lazy_modules = NULL;
+    if (globals != NULL &&
+        PyMapping_GetOptionalItem(globals, &_Py_ID(__lazy_modules__), &lazy_modules) < 0) {
+        return -1;
+    } else if (lazy_modules == NULL) {
+        return 0;
+    }
+
+    int ilevel = PyLong_AsInt(level);
+    if (ilevel == -1 && _PyErr_Occurred(tstate)) {
+        return -1;
+    }
+
+    PyObject *abs_name = _PyImport_GetAbsName(tstate, name, globals, ilevel);
+    if (abs_name == NULL) {
+        return -1;
+    }
+
+    return PySequence_Contains(lazy_modules, abs_name);
+}
 
 PyObject *
 _PyEval_LazyImportName(PyThreadState *tstate, PyObject *builtins, PyObject *globals,
-            PyObject *locals, PyObject *name, PyObject *fromlist, PyObject *level, int lazy)
+                       PyObject *locals, PyObject *name, PyObject *fromlist, PyObject *level, 
+                       int lazy)
 {
     PyObject *res = NULL;
     // Check if global policy overrides the local syntax
@@ -3120,6 +3076,14 @@ _PyEval_LazyImportName(PyThreadState *tstate, PyObject *builtins, PyObject *glob
             break;
     }
 
+    if (!lazy) {
+        // see if __lazy_imports__ forces this to be lazy
+        lazy = check_lazy_import_comatibility(tstate, globals, name, level);
+        if (lazy < 0) {
+            return NULL;
+        }
+    }
+
     if (!lazy) {
         // Not a lazy import or lazy imports are disabled, fallback to the regular import
         return _PyEval_ImportName(tstate, builtins, globals, locals, name, fromlist, level);