has_python, python_version much more robuse

Author: scivision

+stdlib/has_python.m

@@ -4,11 +4,6 @@
 
 function y = has_python()
 
-try
-  pe = pyenv();
-  y = strlength(pe.Version) > 0;
-catch
-  y = false;
-end
+y = ~isempty(stdlib.python_version);
 
 end

+stdlib/python_version.m

@@ -1,12 +1,29 @@
 %% PYTHON_VERSION get the Python version used by MATLAB
+%
+%## Output
+%* 1x3 vector of major, minor, micro version e.g. Python 3.14.2 = [3, 14, 2]
+% we need to do at least one Python function call to handle cases
+% where the environment has changed since pyenv() was set. For example
+% HPC with "module load python3..."
 
 function v = python_version()
 
+v = [];
+
 try
   pe = pyenv();
-  v = pe.Version;
-catch
-  v = "";
+  vs = pe.Version;
+  vi = py.sys.version_info;
+  v = [double(vi.major), double(vi.minor), double(vi.micro)];
+
+  vv = strsplit(vs, '.');
+  assert(str2double(vv{1}) == v(1), "stdlib:python_version:ValueError", "Python major version %s did not match pyenv %d", vv{1}, v(1))
+  assert(str2double(vv{2}) == v(2), "stdlib:python_version:ValueError", "Python minor version %s did not match pyenv %d", vv{1}, v(1))
+catch e
+  switch e.identifier
+    case {'Octave:undefined-function', 'MATLAB:Python:PythonUnavailable'}  % pass
+    otherwise, rethrow(e)
+  end
 end
 
 end

test/TestSys.m

@@ -26,7 +26,7 @@ function test_dotnet_version(tc)
 function test_has_python(tc)
 tc.assumeTrue(stdlib.has_python())
 v = stdlib.python_version();
-tc.verifyTrue(stdlib.version_atleast(v, "3.8"), "expected Python >= 3.8")
+tc.verifyTrue(all(v >= [3, 8, 0]), "expected Python >= 3.8")
 end
 
 function test_os_version(tc)

test/test_nomex.m

@@ -1,13 +1,16 @@
 function test_nomex()
-import matlab.unittest.TestSuite
 import matlab.unittest.selectors.HasTag
 
 cwd = fileparts(mfilename('fullpath'));
 
 root = fileparts(cwd);
 addpath(root)
 
-suite = TestSuite.fromFolder(cwd);
+if isMATLABReleaseOlderThan('R2022b')
+  suite = testsuite(cwd);
+else
+  suite = testsuite(cwd, InvalidFileFoundAction="error");
+end
 
 sel = ~HasTag("exe") & ~HasTag("mex");