Fixed partial variables extended bug and split PartialVarsEnvExtended…

… test into two (#955)

Fixed partial vars bug and split tests

---------

Co-authored-by: jduraniglesias <[email protected]>

cel/cel_test.go

@@ -1733,6 +1733,79 @@ func TestResidualAstAttributeQualifiers(t *testing.T) {
 	}
 }
 
+func TestPartialVarsEnv(t *testing.T) {
+	env := testEnv(t,
+		Variable("x", IntType),
+		Variable("y", IntType),
+	)
+
+	// Use env to make sure internals are all initialized.
+	ast, iss := env.Compile("x == y")
+
+	if iss.Err() != nil {
+		t.Fatalf("env.Compile() failed: %v", iss.Err())
+	}
+	prg, err := env.Program(ast, EvalOptions(OptPartialEval))
+	if err != nil {
+		t.Fatalf("env.Program() failed: %v", err)
+	}
+
+	act, err := env.PartialVars(map[string]any{"x": 1, "y": 1})
+
+	if err != nil {
+		t.Fatalf("env.PartialVars failed: %v", err)
+	}
+	val, _, err := prg.Eval(act)
+	if err != nil {
+		t.Fatalf("Eval failed: %v", err)
+	}
+
+	if val != types.True {
+		t.Fatalf("want: %v, got: %v", types.True, val)
+	}
+}
+
+func TestPartialVarsExtendedEnv(t *testing.T) {
+	env := testEnv(t,
+		Variable("x", IntType),
+		Variable("y", IntType),
+	)
+
+	env.Compile("x == y")
+	// Now test that a sub environment is correctly copied.
+	env2, err := env.Extend(Variable("z", IntType))
+	if err != nil {
+		t.Fatalf("env.Extend failed: %v", err)
+	}
+
+	ast, iss := env2.Compile("x == y && y == z")
+
+	if iss.Err() != nil {
+		t.Fatalf("env.Compile() failed: %v", iss.Err())
+	}
+	prg, err := env2.Program(ast, EvalOptions(OptPartialEval))
+	if err != nil {
+		t.Fatalf("env.Program() failed: %v", err)
+	}
+
+	act, err := env2.PartialVars(map[string]any{"z": 1, "y": 1})
+
+	if err != nil {
+		t.Fatalf("env.PartialVars failed: %v", err)
+	}
+	val, _, err := prg.Eval(act)
+	if err != nil {
+		t.Fatalf("Eval failed: %v", err)
+	}
+	if !types.IsUnknown(val) {
+		t.Fatalf("Wanted unknown, got %v", val)
+	}
+
+	if !reflect.DeepEqual(val, types.NewUnknown(1, types.NewAttributeTrail("x"))) {
+		t.Fatalf("Wanted Unknown(x (1)), got: %v", val)
+	}
+}
+
 func TestResidualAstModified(t *testing.T) {
 	env := testEnv(t,
 		Variable("x", MapType(StringType, IntType)),

cel/env.go

@@ -309,17 +309,13 @@ func (e *Env) Extend(opts ...EnvOption) (*Env, error) {
 	copy(chkOptsCopy, e.chkOpts)
 
 	// Copy the declarations if needed.
-	varsCopy := []*decls.VariableDecl{}
 	if chk != nil {
 		// If the type-checker has already been instantiated, then the e.declarations have been
 		// validated within the chk instance.
 		chkOptsCopy = append(chkOptsCopy, checker.ValidatedDeclarations(chk))
-	} else {
-		// If the type-checker has not been instantiated, ensure the unvalidated declarations are
-		// provided to the extended Env instance.
-		varsCopy = make([]*decls.VariableDecl, len(e.variables))
-		copy(varsCopy, e.variables)
 	}
+	varsCopy := make([]*decls.VariableDecl, len(e.variables))
+	copy(varsCopy, e.variables)
 
 	// Copy macros and program options
 	macsCopy := make([]parser.Macro, len(e.macros))

repl/evaluator.go

@@ -266,9 +266,10 @@ type Optioner interface {
 // EvaluationContext context for the repl.
 // Handles maintaining state for multiple let expressions.
 type EvaluationContext struct {
-	letVars []letVariable
-	letFns  []letFunction
-	options []Optioner
+	letVars           []letVariable
+	letFns            []letFunction
+	options           []Optioner
+	enablePartialEval bool
 }
 
 func (ctx *EvaluationContext) indexLetVar(name string) int {
@@ -311,6 +312,7 @@ func (ctx *EvaluationContext) copy() *EvaluationContext {
 	copy(cpy.letVars, ctx.letVars)
 	cpy.letFns = make([]letFunction, len(ctx.letFns))
 	copy(cpy.letFns, ctx.letFns)
+	cpy.enablePartialEval = ctx.enablePartialEval
 	return &cpy
 }
 
@@ -419,12 +421,16 @@ func (ctx *EvaluationContext) addOption(opt Optioner) {
 
 // programOptions generates the program options for planning.
 // Assumes context has been planned.
-func (ctx *EvaluationContext) programOptions() cel.ProgramOption {
+func (ctx *EvaluationContext) programOptions() []cel.ProgramOption {
 	var fns = make([]*functions.Overload, len(ctx.letFns))
 	for i, fn := range ctx.letFns {
 		fns[i] = fn.generateFunction()
 	}
-	return cel.Functions(fns...)
+	result := []cel.ProgramOption{cel.Functions(fns...)}
+	if ctx.enablePartialEval {
+		result = append(result, cel.EvalOptions(cel.OptPartialEval))
+	}
+	return result
 }
 
 // Evaluator provides basic environment for evaluating an expression with
@@ -489,7 +495,7 @@ func updateContextPlans(ctx *EvaluationContext, env *cel.Env) error {
 			el.ast = ast
 			el.resultType = ast.ResultType()
 
-			plan, err := env.Program(ast, ctx.programOptions())
+			plan, err := env.Program(ast, ctx.programOptions()...)
 			if err != nil {
 				return err
 			}
@@ -579,6 +585,18 @@ func (e *Evaluator) AddOption(opt Optioner) error {
 	return nil
 }
 
+// EnablePartialEval enables the option to allow partial evaluations.
+func (e *Evaluator) EnablePartialEval() error {
+	cpy := e.ctx.copy()
+	cpy.enablePartialEval = true
+	err := updateContextPlans(cpy, e.env)
+	if err != nil {
+		return err
+	}
+	e.ctx = *cpy
+	return nil
+}
+
 // DelLetVar removes a variable from the evaluation context.
 // If deleting the variable breaks a later expression, this function will return an error without modifying the context.
 func (e *Evaluator) DelLetVar(name string) error {
@@ -747,6 +765,11 @@ func (e *Evaluator) setOption(args []string) error {
 			if err != nil {
 				issues = append(issues, fmt.Sprintf("extension: %v", err))
 			}
+		case "--enable_partial_eval":
+			err := e.EnablePartialEval()
+			if err != nil {
+				issues = append(issues, fmt.Sprintf("enable_partial_eval: %v", err))
+			}
 		default:
 			issues = append(issues, fmt.Sprintf("unsupported option '%s'", arg))
 		}
@@ -967,7 +990,12 @@ func (e *Evaluator) Process(cmd Cmder) (string, bool, error) {
 		}
 		if val != nil {
 			t := UnparseType(resultT)
+			unknown, ok := val.Value().(*types.Unknown)
+			if ok {
+				return fmt.Sprintf("Unknown %v", unknown), false, nil
+			}
 			v, err := ext.FormatString(val, "")
+
 			if err != nil {
 				// Default format if type is unsupported by ext.Strings formatter.
 				return fmt.Sprintf("%v : %s", val.Value(), t), false, nil
@@ -1039,11 +1067,12 @@ func (e *Evaluator) Evaluate(expr string) (ref.Val, *exprpb.Type, error) {
 		return nil, nil, iss.Err()
 	}
 
-	p, err := env.Program(ast, e.ctx.programOptions())
+	p, err := env.Program(ast, e.ctx.programOptions()...)
 	if err != nil {
 		return nil, nil, err
 	}
 
+	act, _ = env.PartialVars(act)
 	val, _, err := p.Eval(act)
 	// expression can be well-formed and result in an error
 	return val, ast.ResultType(), err

repl/evaluator_test.go

@@ -716,7 +716,81 @@ func TestProcess(t *testing.T) {
 			wantExit:  false,
 			wantError: false,
 		},
-
+		{
+			name: "OptionEnablePartialEval",
+			commands: []Cmder{
+				&simpleCmd{
+					cmd: "option",
+					args: []string{
+						"--enable_partial_eval",
+					},
+				},
+				&letVarCmd{
+					identifier: "x",
+					typeHint:   mustParseType(t, "int"),
+					src:        "",
+				},
+				&letVarCmd{
+					identifier: "y",
+					typeHint:   mustParseType(t, "int"),
+					src:        "10",
+				},
+				&evalCmd{
+					expr: "x + y > 10 || y > 10",
+				},
+			},
+			wantText:  "Unknown x (1)",
+			wantExit:  false,
+			wantError: false,
+		},
+		{
+			name: "PartialEvalDisabled",
+			commands: []Cmder{
+				&letVarCmd{
+					identifier: "x",
+					typeHint:   mustParseType(t, "int"),
+					src:        "",
+				},
+				&letVarCmd{
+					identifier: "y",
+					typeHint:   mustParseType(t, "int"),
+					src:        "10",
+				},
+				&evalCmd{
+					expr: "x + y > 10 || y > 10",
+				},
+			},
+			wantText:  "",
+			wantExit:  false,
+			wantError: true,
+		},
+		{
+			name: "PartialEvalFiltered",
+			commands: []Cmder{
+				&simpleCmd{
+					cmd: "option",
+					args: []string{
+						"--enable_partial_eval",
+					},
+				},
+				&letVarCmd{
+					identifier: "x",
+					typeHint:   mustParseType(t, "int"),
+					src:        "",
+				},
+				&letVarCmd{
+					identifier: "y",
+					typeHint:   mustParseType(t, "int"),
+					src:        "11",
+				},
+				&evalCmd{
+					expr: "x + y > 10 || y > 10",
+				},
+			},
+			wantText:  "true : bool",
+			wantExit:  false,
+			wantError: false,
+		},
 		{
 			name: "LoadDescriptorsError",
 			commands: []Cmder{

repl/main/README.md

@@ -161,6 +161,8 @@ may take string arguments.
 `--extension <extensionType>` enables CEL extensions. Valid options are: 
 `strings`, `protos`, `math`, `encoders`, `optional`, `bindings`, and `all`.
 
+`--enable_partial_eval` enables partial evaluations
+
 example:
 
 `%option --container 'google.protobuf'` 
@@ -169,6 +171,8 @@ example:
 
 `%option --extension 'all'` (Loads all extensions)
 
+`%option --enable_partial_eval`
+
 #### reset
 
 `%reset` drops all options and let expressions, returning the evaluator to a