'python2 --version' sends output to stderr, redirect to stdout to cat…

recipes/qt/5.x.x/conanfile.py

@@ -14,6 +14,7 @@
 import os
 import textwrap
 import shutil
+import subprocess
 
 required_conan_version = ">=1.60.0 <2 || >=2.0.5"
 
@@ -148,12 +149,14 @@
                        "in order to build Qt WebEngine")
                 raise ConanInvalidConfiguration(msg)
 
-            # In any case, check its actual version for compatibility
-            from six import StringIO  # Python 2 and 3 compatible
-            mybuf = StringIO()
-            cmd_v = f"\"{python_exe}\" --version"
-            self.run(cmd_v, mybuf)
-            verstr = mybuf.getvalue().strip().split("Python ")[1]
+            # In any case, check its actual version for compatibility.
+            # Note that python2 exe sends its version to stderr instead of stdout.
+            completed = subprocess.run( [python_exe, '--version'], stderr=subprocess.PIPE,
+                                            timeout=5 )
+            if completed.returncode != 0:
+                msg = ("Found python2 executable %s but could not run it" % python_exe)
+                raise ConanInvalidConfiguration(msg)
+            verstr = completed.stderr.decode('utf-8').split("Python ")[1]
             if verstr.endswith("+"):
                 verstr = verstr[:-1]
             version = Version(verstr)
@@ -162,7 +165,7 @@
             v_max = "3.0.0"
             if (version >= v_min) and (version < v_max):
                 msg = ("Found valid Python 2 required for QtWebengine:"
-                       f" version={mybuf.getvalue()}, path={python_exe}")
+                       f" version={verstr}, path={python_exe}")
                 self.output.success(msg)
             else:
                 msg = (f"Found Python 2 in path, but with invalid version {verstr}"
@@ -925,7 +928,7 @@
         filecontents += 'set(CMAKE_AUTOMOC_MACRO_NAMES "Q_OBJECT" "Q_GADGET" "Q_GADGET_EXPORT" "Q_NAMESPACE" "Q_NAMESPACE_EXPORT")\n'
         save(self, os.path.join(self.package_folder, self._cmake_core_extras_file), filecontents)
 
         def _create_private_module(module, dependencies=[]):
             if "Core" not in dependencies:
                 dependencies.append("Core")
             dependencies_string = ';'.join(f'Qt5::{dependency}' for dependency in dependencies)
@@ -994,7 +997,7 @@
                 reqs.append(corrected_req)
             return reqs
 
         def _create_module(module, requires=[], has_include_dir=True):
             componentname = f"qt{module}"
             assert componentname not in self.cpp_info.components, f"Module {module} already present in self.cpp_info.components"
             self.cpp_info.components[componentname].set_property("cmake_target_name", f"Qt5::{module}")