Fix crash when z3 is missing and add transform error reporting

CHANGELOG.md

@@ -18,6 +18,7 @@ and adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 - Added a STRICT_NUMERIC_TYPES configuration to `python_ta.contracts` allowing to enable/disable stricter type checking of numeric types
 - Added integration with MemoryViz Webstepper
 - Added `z3` option to `one-iteration-checker` to only check for feasible code blocks based on edge z3 constraints
+- Added reporting for errors raised by custom transforms (`Z3Visitor`, `CFGVisitor`)
 
 ### 💫 New checkers
 
@@ -34,6 +35,7 @@ and adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 - Added strict type checking support for nested and union types (e.g., `list[int]`, `dict[float, int]`, `Union[int, float]`)
 - Fixed issue where CFG edges from loop body to loop condition block was ignored during augmenting edge z3 constraints
 - Fixed issue in `one-iteration-checker` where the message was not correctly reported for `while` loops when `z3` option is on
+- Fixed crash when z3-solver is not installed
 
 ### 🔧 Internal changes
 

python_ta/patches/transforms.py

@@ -1,24 +1,36 @@
 """Patch to add transforms for setting type constraints and creating control flow graphs.
 """
 
+import logging
+
 from pylint.lint import PyLinter
 
 from ..cfg.visitor import CFGVisitor
-from ..transforms.z3_visitor import Z3Visitor
 
 
 def patch_ast_transforms(z3: bool):
     old_get_ast = PyLinter.get_ast
 
     def new_get_ast(self, filepath, modname, data):
         ast = old_get_ast(self, filepath, modname, data)
-        if ast is not None:
+        if ast is None:
+            return None
+
+        # Run the Z3Visitor
+        if z3:
             try:
-                if z3:
-                    ast = Z3Visitor().visitor.visit(ast)
-                ast.accept(CFGVisitor())
-            except:
-                pass
+                from ..transforms.z3_visitor import Z3Visitor
+
+                ast = Z3Visitor().visitor.visit(ast)
+            except Exception as e:
+                logging.warning(f"Could not run Z3Visitor: {e}")
+
+        # Run the CFGVisitor
+        try:
+            ast.accept(CFGVisitor())
+        except Exception as e:
+            logging.warning(f"Could not run Z3Visitor: {e}")
+
         return ast
 
     PyLinter.get_ast = new_get_ast