PR: Improve validation for the right Spyder-kernels version

spyder/plugins/ipythonconsole/__init__.py

@@ -10,3 +10,18 @@
 
 IPython Console plugin based on QtConsole
 """
+
+# Required version of Spyder-kernels
+SPYDER_KERNELS_MIN_VERSION = '2.3.0'
+SPYDER_KERNELS_MAX_VERSION = '2.4.0'
+SPYDER_KERNELS_VERSION = (
+    f'>={SPYDER_KERNELS_MIN_VERSION};<{SPYDER_KERNELS_MAX_VERSION}')
+SPYDER_KERNELS_CONDA = (
+    f'conda install spyder&#45;kernels={SPYDER_KERNELS_MIN_VERSION[:-2]}')
+SPYDER_KERNELS_PIP = (
+    f'pip install spyder&#45;kernels=={SPYDER_KERNELS_MIN_VERSION[:-1]}*')
+
+
+class SpyderKernelError(RuntimeError):
+    """Error to be shown in client."""
+    pass

spyder/plugins/ipythonconsole/tests/test_ipythonconsole.py

@@ -2387,5 +2387,39 @@ def test_varexp_magic_dbg_locals(ipyconsole, qtbot):
     assert shell._control.toHtml().count('img src') == 1
 
 
+@pytest.mark.skipif(os.name == 'nt', reason="Fails on windows")
+def test_old_kernel_version(ipyconsole, qtbot):
+    """
+    Check that an error is shown when an version of spyder-kernels is used.
+    """
+    # Set a false _spyder_kernels_version in the cached kernel
+    w = ipyconsole.get_widget()
+    # create new client so PYTEST_CURRENT_TEST is the same
+    w.create_new_client()
+    # Wait until the window is fully up
+    shell = ipyconsole.get_current_shellwidget()
+    qtbot.waitUntil(
+        lambda: shell._prompt_html is not None, timeout=SHELL_TIMEOUT)
+
+    kc = w._cached_kernel_properties[-1][2]
+    kc.start_channels()
+    kc.execute("get_ipython()._spyder_kernels_version = ('1.0.0', '')")
+    # Cleanup the kernel_client so it can be used again
+    kc.stop_channels()
+    kc._shell_channel = None
+    kc._iopub_channel = None
+    kc._stdin_channel = None
+    kc._hb_channel = None
+    kc._control_channel = None
+
+    # Create new client
+    w.create_new_client()
+    client = w.get_current_client()
+
+    # Make sure an error is shown
+    qtbot.waitUntil(lambda: client.error_text is not None)
+    assert '1.0.0' in client.error_text
+
+
 if __name__ == "__main__":
     pytest.main()

spyder/plugins/ipythonconsole/utils/kernelspec.py

@@ -19,19 +19,43 @@
 
 # Local imports
 from spyder.api.config.mixins import SpyderConfigurationAccessor
+from spyder.api.translations import get_translation
 from spyder.config.base import (get_safe_mode, is_pynsist, running_in_mac_app,
                                 running_under_pytest)
+from spyder.plugins.ipythonconsole import (
+    SPYDER_KERNELS_CONDA, SPYDER_KERNELS_PIP, SpyderKernelError)
 from spyder.utils.conda import (add_quotes, get_conda_activation_script,
                                 get_conda_env_path, is_conda_env)
 from spyder.utils.environ import clean_env
 from spyder.utils.misc import get_python_executable
-from spyder.utils.programs import is_python_interpreter
+from spyder.utils.programs import is_python_interpreter, is_module_installed
 
 # Constants
 HERE = os.path.abspath(os.path.dirname(__file__))
 logger = logging.getLogger(__name__)
 
 
+# Localization
+_ = get_translation('spyder')
+
+ERROR_SPYDER_KERNEL_INSTALLED = _(
+    "The Python environment or installation whose interpreter is located at"
+    "<pre>"
+    "    <tt>{0}</tt>"
+    "</pre>"
+    "doesn't have the <tt>spyder-kernels</tt> module installed. Without this "
+    "module is not possible for Spyder to create a console for you.<br><br>"
+    "You can install it by activating your environment (if necessary) and "
+    "running in a system terminal:"
+    "<pre>"
+    "    <tt>{1}</tt>"
+    "</pre>"
+    "or"
+    "<pre>"
+    "    <tt>{2}</tt>"
+    "</pre>")
+
+
 def is_different_interpreter(pyexec):
     """Check that pyexec is a different interpreter from sys.executable."""
     executable_validation = osp.basename(pyexec).startswith('python')
@@ -59,6 +83,13 @@ def get_activation_script(quote=False):
     return script_path
 
 
+def has_spyder_kernels(pyexec):
+    """Check if env has spyder kernels."""
+    return is_module_installed(
+        'spyder_kernels',
+        interpreter=pyexec)
+
+
 HERE = osp.dirname(os.path.realpath(__file__))
 
 
@@ -86,6 +117,15 @@ def argv(self):
             pyexec = get_python_executable()
         else:
             pyexec = self.get_conf('executable', section='main_interpreter')
+            if not has_spyder_kernels(pyexec):
+                raise SpyderKernelError(
+                    ERROR_SPYDER_KERNEL_INSTALLED.format(
+                          pyexec,
+                          SPYDER_KERNELS_CONDA,
+                          SPYDER_KERNELS_PIP
+                      )
+                )
+                return
             if not is_python_interpreter(pyexec):
                 pyexec = get_python_executable()
                 self.set_conf('executable', '', section='main_interpreter')

spyder/plugins/ipythonconsole/widgets/main_widget.py

@@ -33,6 +33,7 @@
 from spyder.api.widgets.menus import MENU_SEPARATOR
 from spyder.config.base import (
     get_conf_path, get_home_dir, running_under_pytest)
+from spyder.plugins.ipythonconsole import SpyderKernelError
 from spyder.plugins.ipythonconsole.utils.kernelspec import SpyderKernelSpec
 from spyder.plugins.ipythonconsole.utils.manager import SpyderKernelManager
 from spyder.plugins.ipythonconsole.utils.client import SpyderKernelClient
@@ -58,17 +59,6 @@
 # ---- Constants
 # =============================================================================
 MAIN_BG_COLOR = QStylePalette.COLOR_BACKGROUND_1
-SPYDER_KERNELS_MIN_VERSION = '2.3.0'
-SPYDER_KERNELS_MAX_VERSION = '2.4.0'
-SPYDER_KERNELS_VERSION = (
-    f'>={SPYDER_KERNELS_MIN_VERSION};<{SPYDER_KERNELS_MAX_VERSION}')
-SPYDER_KERNELS_VERSION_MSG = _(
-    '>= {0} and < {1}').format(
-        SPYDER_KERNELS_MIN_VERSION, SPYDER_KERNELS_MAX_VERSION)
-SPYDER_KERNELS_CONDA = (
-    f'conda install spyder&#45;kernels={SPYDER_KERNELS_MIN_VERSION[:-2]}')
-SPYDER_KERNELS_PIP = (
-    f'pip install spyder&#45;kernels=={SPYDER_KERNELS_MIN_VERSION[:-1]}*')
 
 
 class IPythonConsoleWidgetActions:
@@ -1486,42 +1476,6 @@ def create_new_client(self, give_focus=True, filename='', is_cython=False,
             client.show_kernel_error(error_msg)
             return
 
-        # Check if ipykernel is present in the external interpreter.
-        # Else we won't be able to create a client
-        if not self.get_conf('default', section='main_interpreter'):
-            pyexec = self.get_conf('executable', section='main_interpreter')
-            has_spyder_kernels = programs.is_module_installed(
-                'spyder_kernels',
-                interpreter=pyexec,
-                version=SPYDER_KERNELS_VERSION)
-            if not has_spyder_kernels and not running_under_pytest():
-                client.show_kernel_error(
-                    _("The Python environment or installation whose "
-                      "interpreter is located at"
-                      "<pre>"
-                      "    <tt>{0}</tt>"
-                      "</pre>"
-                      "doesn't have the <tt>spyder-kernels</tt> module or the "
-                      "right version of it installed ({1}). "
-                      "Without this module is not possible for Spyder to "
-                      "create a console for you.<br><br>"
-                      "You can install it by activating your environment (if "
-                      "necessary) and then running in a system terminal:"
-                      "<pre>"
-                      "    <tt>{2}</tt>"
-                      "</pre>"
-                      "or"
-                      "<pre>"
-                      "    <tt>{3}</tt>"
-                      "</pre>").format(
-                          pyexec,
-                          SPYDER_KERNELS_VERSION_MSG,
-                          SPYDER_KERNELS_CONDA,
-                          SPYDER_KERNELS_PIP
-                      )
-                )
-                return
-
         self.connect_client_to_kernel(client, km, kc)
         if client.shellwidget.kernel_manager is None:
             return
@@ -1653,16 +1607,14 @@ def create_client_for_kernel(self, connection_file, hostname, sshkey,
         # Assign kernel manager and client to shellwidget
         kernel_client.start_channels()
         shellwidget = client.shellwidget
-        shellwidget.set_kernel_client_and_manager(
-            kernel_client, kernel_manager)
-        shellwidget.sig_exception_occurred.connect(
-            self.sig_exception_occurred)
 
         if not known_spyder_kernel:
             shellwidget.sig_is_spykernel.connect(
                 self.connect_external_spyder_kernel)
-            shellwidget.check_spyder_kernel()
-
+        shellwidget.set_kernel_client_and_manager(
+            kernel_client, kernel_manager)
+        shellwidget.sig_exception_occurred.connect(
+            self.sig_exception_occurred)
         self.sig_shellwidget_created.emit(shellwidget)
         kernel_client.stopped_channels.connect(
             lambda: self.sig_shellwidget_deleted.emit(shellwidget))
@@ -2131,6 +2083,8 @@ def create_kernel_manager_and_kernel_client(self, connection_file,
                 config=None,
                 autorestart=True,
             )
+        except SpyderKernelError as e:
+            return (e.args[0], None)
         except Exception:
             error_msg = _("The error is:<br><br>"
                           "<tt>{}</tt>").format(traceback.format_exc())
@@ -2143,6 +2097,8 @@ def create_kernel_manager_and_kernel_client(self, connection_file,
             kernel_manager.start_kernel(stderr=stderr_handle,
                                         stdout=stdout_handle,
                                         env=kernel_spec.env)
+        except SpyderKernelError as e:
+            return (e.args[0], None)
         except Exception:
             error_msg = _("The error is:<br><br>"
                           "<tt>{}</tt>").format(traceback.format_exc())