Fix duplicate SV struct typedefs when multiple APIs share same struct type

Co-authored-by: mballance <1340805+mballance@users.noreply.github.com>

Author: Copilot

src/hdl_if/impl/call/gen_sv_class.py

@@ -37,6 +37,7 @@ def __init__(self, out, ind="", uvm=False, deprecated=False):
         self._deprecated = deprecated
         self._have_imp = False
         self._struct_types = set()  # Track struct types used in API
+        self._emitted_struct_types = set()  # Track struct types already emitted (across multiple gen() calls)
         pass
 
     def _collect_methods(self, api: ApiDef):
@@ -93,16 +94,20 @@ def gen(self, api : ApiDef):
         # Collect struct types used in the API
         self._collect_struct_types(api)
 
-        # Generate struct typedefs
-        if self._struct_types:
-            for struct_type in sorted(self._struct_types, key=lambda t: t.__name__):
+        # Generate struct typedefs only for types not already emitted
+        new_struct_types = self._struct_types - self._emitted_struct_types
+        if new_struct_types:
+            for struct_type in sorted(new_struct_types, key=lambda t: t.__name__):
                 self.gen_struct_typedef(struct_type)
                 self.println()
 
-            # Generate conversion functions for each struct
-            for struct_type in sorted(self._struct_types, key=lambda t: t.__name__):
+            # Generate conversion functions for each new struct
+            for struct_type in sorted(new_struct_types, key=lambda t: t.__name__):
                 self.gen_struct_conversion_functions(struct_type)
                 self.println()
+            
+            self._emitted_struct_types.update(new_struct_types)
+        self._struct_types = set()
 
         # Existing class generation (unchanged)
 #        self.gen_class_interface_exp(api)

tests/unit/test_api_gen_sv_filtering.py

@@ -450,3 +450,45 @@ def __init__(self):
         assert len(filtered) == 3
         names = [a.name for a in filtered]
         assert names == ["First", "Second", "Third"]
+
+    def test_no_duplicate_struct_typedefs_across_apis(self):
+        """Test that struct typedefs are not duplicated when multiple APIs share the same struct type."""
+
+        class Point(ct.Structure):
+            _fields_ = [
+                ("x", ct.c_int32),
+                ("y", ct.c_int32),
+            ]
+
+        @api
+        class FirstAPI(object):
+            @imp
+            async def func1(self, pt: Point):
+                pass
+
+        @api
+        class SecondAPI(object):
+            @exp
+            def func2(self, pt: Point):
+                pass
+
+        all_apis = ApiDefRgy.inst().getApis()
+
+        out = io.StringIO()
+        gen = GenSVClass(out, ind="", uvm=False, deprecated=False)
+        for a in all_apis:
+            gen.gen(a)
+        sv_content = out.getvalue()
+
+        # Count occurrences of the struct typedef — must appear exactly once
+        typedef_count = sv_content.count("typedef struct")
+        assert typedef_count == 1, (
+            f"Expected 1 struct typedef for Point_t, but found {typedef_count}. "
+            f"Duplicate typedefs cause SV compilation errors."
+        )
+        # Conversion function definitions must also appear exactly once
+        # (the name may also appear in calls within API method bodies)
+        assert sv_content.count("function Point_t pyhdl_if_py_to_struct_Point") == 1, \
+            "pyhdl_if_py_to_struct_Point conversion function definition duplicated"
+        assert sv_content.count("function pyhdl_if::PyObject pyhdl_if_struct_to_py_Point") == 1, \
+            "pyhdl_if_struct_to_py_Point conversion function definition duplicated"