python · serhiy-storchaka · May 16, 2018 · May 16, 2018 · May 18, 2018 · May 18, 2018
diff --git a/Doc/c-api/capsule.rst b/Doc/c-api/capsule.rst
@@ -102,13 +102,15 @@ Refer to :ref:`using-capsules` for more information on using these objects.
    Import a pointer to a C object from a capsule attribute in a module.  The
    *name* parameter should specify the full name to the attribute, as in
    ``module.attribute``.  The *name* stored in the capsule must match this
-   string exactly.  If *no_block* is true, import the module without blocking
-   (using :c:func:`PyImport_ImportModuleNoBlock`).  If *no_block* is false,
-   import the module conventionally (using :c:func:`PyImport_ImportModule`).
+   string exactly.
 
    Return the capsule's internal *pointer* on success.  On failure, set an
    exception and return *NULL*.
 
+   .. versionchanged:: 3.8
+      Supported importing submodules as in ``package.module.attribute``.
+      *no_block* is ignored.
+
 
 .. c:function:: int PyCapsule_IsValid(PyObject *capsule, const char *name)
 

diff --git a/Misc/NEWS.d/next/C API/2018-05-16-13-47-18.bpo-32414.NODPbj.rst b/Misc/NEWS.d/next/C API/2018-05-16-13-47-18.bpo-32414.NODPbj.rst
@@ -0,0 +1,3 @@
+:c:func:`PyCapsule_Import` now imports submodules if needed.  Previously
+names like ``package.module.attribute`` worked only if ``package.module``
+was already imported.
diff --git a/Objects/capsule.c b/Objects/capsule.c
@@ -192,63 +192,52 @@ PyCapsule_SetContext(PyObject *o, void *context)
 
 
 void *
-PyCapsule_Import(const char *name, int no_block)
+PyCapsule_Import(const char *name, int Py_UNUSED(no_block))
 {
     PyObject *object = NULL;
     void *return_value = NULL;
     char *trace;
-    size_t name_length = (strlen(name) + 1) * sizeof(char);
-    char *name_dup = (char *)PyMem_MALLOC(name_length);
+    char *name_dup = _PyMem_Strdup(name);
 
     if (!name_dup) {
         return NULL;
     }
 
-    memcpy(name_dup, name, name_length);
-
     trace = name_dup;
-    while (trace) {
+    while (1) {
         char *dot = strchr(trace, '.');
         if (dot) {
-            *dot++ = '\0';
+            *dot = '\0';
         }
-
-        if (object == NULL) {
-            if (no_block) {
-                object = PyImport_ImportModuleNoBlock(trace);
-            } else {
-                object = PyImport_ImportModule(trace);
-                if (!object) {
-                    PyErr_Format(PyExc_ImportError, "PyCapsule_Import could not import module \"%s\"", trace);
-                }
-            }
-        } else {
-            PyObject *object2 = PyObject_GetAttrString(object, trace);
-            Py_DECREF(object);
-            object = object2;
+        if (object) {
+            Py_SETREF(object, PyObject_GetAttrString(object, trace));
+        }
+        if (!dot) {
+            break;
         }
         if (!object) {
-            goto EXIT;
+            object = PyImport_ImportModule(name_dup);
+            if (!object) {
+                break;
+            }
         }
-
-        trace = dot;
+        *dot = '.';
+        trace = dot + 1;
     }
 
     /* compare attribute name to module.name by hand */
     if (PyCapsule_IsValid(object, name)) {
         PyCapsule *capsule = (PyCapsule *)object;
         return_value = capsule->pointer;
-    } else {
+    }
+    else if (object || trace == name_dup) {
         PyErr_Format(PyExc_AttributeError,
             "PyCapsule_Import \"%s\" is not valid",
             name);
     }
 
-EXIT:
     Py_XDECREF(object);
-    if (name_dup) {
-        PyMem_FREE(name_dup);
-    }
+    PyMem_Free(name_dup);
     return return_value;
 }