signature: Use a clean init function to initialize it

After the quick hack replacing "type.__signature__" by
'eval("type.__signature__")', we now use a clean initialization
function `_init_pyside_extension` that is implanted into the
__builtins__ module.

This is the first of a series of improvements and simplifications
that will be applied slowly with low priority.

Task-number: PYSIDE-829
Task-number: PYSIDE-510
Change-Id: I9951239c73d02f47272f1a531fb4886c8181b9a7
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>

5 files changed, 28 insertions, 7 deletions

diff --git a/sources/shiboken2/libshiboken/embed/signature_bootstrap.py b/sources/shiboken2/libshiboken/embed/signature_bootstrap.py
index 3a74bb42e..b7d9d2793 100644
--- a/sources/shiboken2/libshiboken/embed/signature_bootstrap.py
+++ b/sources/shiboken2/libshiboken/embed/signature_bootstrap.py
@@ -73,7 +73,7 @@ def bootstrap():
     if recursion_trap:
         # we are probably called from outside, already
         print("Recursion occurred in Bootstrap. Did you start by hand? Then it's ok.")
-        print("""But you should trigger start by 'eval("type.__signature__")', only!""")
+        print("But you should trigger start by '_init_pyside_extension()', only!")
     recursion_trap += 1
 
     @contextmanager
diff --git a/sources/shiboken2/libshiboken/signature.cpp b/sources/shiboken2/libshiboken/signature.cpp
index e2c02a196..70f1e8de7 100644
--- a/sources/shiboken2/libshiboken/signature.cpp
+++ b/sources/shiboken2/libshiboken/signature.cpp
@@ -98,6 +98,7 @@ static PyObject *PySide_BuildSignatureProps(PyObject *class_mod);
 
 static void init_module_1(void);
 static void init_module_2(void);
+static PyObject *_init_pyside_extension(PyObject * /* self */, PyObject * /* args */);
 
 static PyObject *
 CreateSignature(PyObject *props, PyObject *key)
@@ -486,8 +487,14 @@ static const unsigned char PySide_SignatureLoader[] = {
 #include "embed/signature_bootstrap_inc.h"
     };
 
+// This function will be inserted into __builtins__.
+static PyMethodDef init_methods[] = {
+    {"_init_pyside_extension", (PyCFunction)_init_pyside_extension, METH_NOARGS},
+    {nullptr, nullptr}
+};
+
 static safe_globals_struc *
-init_phase_1(void)
+init_phase_1(PyMethodDef *init_meth)
 {
     {
         auto *p = reinterpret_cast<safe_globals_struc *>
@@ -582,6 +589,12 @@ init_phase_1(void)
         // This function will be disabled until phase 2 is done.
         p->finish_import_func = nullptr;
 
+        // Initialize the explicit init function.
+        Shiboken::AutoDecRef init(PyCFunction_NewEx(init_meth, nullptr, nullptr));
+        if (init.isNull()
+            || PyDict_SetItemString(PyEval_GetBuiltins(), init_meth->ml_name, init) != 0)
+            goto error;
+
         return p;
     }
 error:
@@ -870,6 +883,14 @@ get_signature(PyObject * /* self */, PyObject *args)
     Py_RETURN_NONE;
 }
 
+static PyObject *
+_init_pyside_extension(PyObject * /* self */, PyObject * /* args */)
+{
+    init_module_1();
+    init_module_2();
+    Py_RETURN_NONE;
+}
+
 ////////////////////////////////////////////////////////////////////////////
 //
 // This special Type_Ready does certain initializations earlier with
@@ -955,7 +976,7 @@ init_module_1(void)
     static int init_done = 0;
 
     if (!init_done) {
-        pyside_globals = init_phase_1();
+        pyside_globals = init_phase_1(init_methods);
         if (pyside_globals != nullptr)
             init_done = 1;
     }
diff --git a/sources/shiboken2/shibokenmodule/__init__.py.in b/sources/shiboken2/shibokenmodule/__init__.py.in
index eb392e847..6ba8929c9 100644
--- a/sources/shiboken2/shibokenmodule/__init__.py.in
+++ b/sources/shiboken2/shibokenmodule/__init__.py.in
@@ -26,5 +26,5 @@ if sys.version_info[0] == 3:
 
 from .shiboken2 import *
 
-# Trigger signature initialization.
-eval("type.__signature__")
+# Trigger signature initialization via __builtins__.
+_init_pyside_extension()
diff --git a/sources/shiboken2/tests/minimalbinding/brace_pattern_test.py b/sources/shiboken2/tests/minimalbinding/brace_pattern_test.py
index bcaccac44..550a609cb 100644
--- a/sources/shiboken2/tests/minimalbinding/brace_pattern_test.py
+++ b/sources/shiboken2/tests/minimalbinding/brace_pattern_test.py
@@ -49,7 +49,7 @@ from shiboken_paths import init_paths
 init_paths()
 
 import shiboken2
-eval("type.__signature__")   # trigger bootstrap
+_init_pyside_extension()   # trigger bootstrap
 
 from shibokensupport.signature.lib.tool import build_brace_pattern
 
diff --git a/sources/shiboken2/tests/samplebinding/pointerprimitivetype_test.py b/sources/shiboken2/tests/samplebinding/pointerprimitivetype_test.py
index 3abd01cd9..648b35e41 100644
--- a/sources/shiboken2/tests/samplebinding/pointerprimitivetype_test.py
+++ b/sources/shiboken2/tests/samplebinding/pointerprimitivetype_test.py
@@ -54,7 +54,7 @@ init_paths()
 from sample import IntArray2, VirtualMethods
 
 import shiboken2
-eval("type.__signature__")   # trigger init, which does not happen in tests
+_init_pyside_extension()   # trigger init, which does not happen in tests
 from shibokensupport.signature import typing