[Frontend-go] Add unit test 4 with fixes on index/slicing expression type detection (#1973)

* [Frontend-go] Add unit test for object type detect and fix logic

Signed-off-by: Arthur Chan <[email protected]>

* [Frontend-go] Fix for index/slicing expression type detection

Signed-off-by: Arthur Chan <[email protected]>

* Fix formatting

Signed-off-by: Arthur Chan <[email protected]>

---------

Signed-off-by: Arthur Chan <[email protected]>

Author: arthurscchan

src/fuzz_introspector/frontends/frontend_go.py

@@ -222,6 +222,12 @@ def dump_module_logic(self,
             for func_def in functions_methods:
                 func_def.extract_local_variable_type(
                     self.functions_methods_map)
+                # Need a second pass because the processing may out of order
+                # That could affect some local variable types that are
+                # relying on other variables
+                func_def.extract_local_variable_type(
+                    self.functions_methods_map)
+
                 func_def.extract_callsites(self.functions_methods_map)
                 func_dict: dict[str, Any] = {}
                 func_dict['functionName'] = func_def.function_name
@@ -663,10 +669,15 @@ def _detect_variable_type(
                 if target_name:
                     return target_name
 
-                # TODO Handles the following type
-                # index_expression slice_expression
-                # type_assertion_expression type_conversion_expression
-                # type_instantiation_expression
+            # Index expression / Slice expression
+            elif child.type in ['index_expression', 'slice_expression']:
+                op = child.child_by_field_name('operand')
+                parent_type = self.var_map.get(op.text.decode())
+                if parent_type:
+                    if '[' in parent_type and ']' in parent_type:
+                        return parent_type.rsplit(']', 1)[-1]
+                    elif parent_type == 'string':
+                        return 'uint8'
 
             # Other expression that need to recursive deeper
             # unary_expression binary_expression
@@ -680,8 +691,6 @@ def extract_local_variable_type(self,
                                     all_funcs_meths: dict[str,
                                                           'FunctionMethod']):
         """Gets the local variable types of the function."""
-        # TODO The handling of all kind of variable declaration approach is not done.
-        # There are some requires extensive search to determine a type.
 
         query = self.tree_sitter_lang.query('( var_declaration ) @vd')
         for _, exprs in query.captures(self.root).items():

src/test/data/source-code/go/test-project-4/fuzzer.go

@@ -0,0 +1,109 @@
+// Copyright 2025 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+package structs
+
+import (
+	"testing"
+	"fmt"
+	"strconv"
+)
+
+type Person struct {
+	Name string
+	Age  int
+}
+
+func (p Person) Greet() string {
+	return fmt.Sprintf("Hello, my name is %s and I am %d years old.", p.Name, p.Age)
+}
+
+func (p Person) Introduce() string {
+	return fmt.Sprintf("I am %s, a person of age %d.", p.Name, p.Age)
+}
+
+func (p Person) Describe() string {
+	return fmt.Sprintf("Person: %s, Age: %d", p.Name, p.Age)
+}
+
+type Dog struct {
+	Name string
+}
+
+func (d Dog) Greet() string {
+	return fmt.Sprintf("Hello, my dog's name is %s.", d.Name)
+}
+
+func (d Dog) Introduce() string {
+	return fmt.Sprintf("This is my dog, %s.", d.Name)
+}
+
+func (d Dog) Describe() string {
+	return fmt.Sprintf("Dog: %s", d.Name)
+}
+
+func NewDog(name string) Dog {
+	return Dog{Name: name}
+}
+
+type Robot struct {
+	Model string
+}
+
+func (r Robot) Greet() string {
+	return fmt.Sprintf("Hello, I am a robot of model %s.", r.Model)
+}
+
+func (r Robot) Introduce() string {
+	return fmt.Sprintf("I am %s, a highly advanced robot.", r.Model)
+}
+
+func (r Robot) Describe() string {
+	return fmt.Sprintf("Robot Model: %s", r.Model)
+}
+
+func FuzzStructs(f *testing.F) {
+	f.Fuzz(func(t *testing.T, name string, ageString string, model string) {
+		age, err := strconv.Atoi(ageString)
+		if err != nil {
+			return
+		}
+
+		personMap := map[int]Person{
+			0: {Name: "Default", Age: 0},
+			1: {Name: name, Age: age},
+		}
+		p := personMap[1]
+
+		var dogInterface interface{} = Dog{Name: name}
+		d, ok := dogInterface.(Dog)
+		if !ok {
+			return
+		}
+
+		d := NewDog(name)
+
+		robots := [3]Robot{
+			{Model: "X-1000"},
+			{Model: "R2-D2"},
+			{Model: model},
+		}
+		r := robots[0]
+
+		_ = p.Greet()
+		_ = d.Introduce()
+		_ = r.Describe()
+	})
+}

src/test/test_frontends_go.py

@@ -91,7 +91,21 @@ def test_tree_sitter_go_sample4():
 
     # Project check
     harness = project.get_source_codes_with_harnesses()
-    assert len(harness) == 0
+    assert len(harness) == 1
+
+    functions_reached = project.get_reachable_functions(harness[0].source_file, harness[0])
+
+    # Callsite check
+    assert 'strconv.Atoi' in functions_reached
+    assert 'Person.Greet' in functions_reached
+    assert 'Dog.Introduce' in functions_reached
+    assert 'Robot.Describe' in functions_reached
+    assert 'Person.Introduce' not in functions_reached
+    assert 'Person.Describe' not in functions_reached
+    assert 'Dog.Greet' not in functions_reached
+    assert 'Dog.Describe' not in functions_reached
+    assert 'Robot.Greet' not in functions_reached
+    assert 'Robot.Introduce' not in functions_reached
 
 
 def test_tree_sitter_go_sample5():