still not hitting every env condition ugh

env.go

@@ -53,9 +53,9 @@ func (e *env) load(dest Test) error {
 	destV := reflect.ValueOf(dest).Elem()
 	destT := destV.Type()
 
-	e = e.match(dest)
+	e, err := e.match(dest)
-	if e == nil {
+	if err != nil {
-		return fmt.Errorf("failed to find a matching environment")
+		return fmt.Errorf("match failed: %w", err)
 	}
 
 	for i := 0; i < destT.NumField(); i++ {
@@ -86,23 +86,29 @@ func (e *env) load(dest Test) error {
 		}
 
 		if !set {
-			return fmt.Errorf("failed to set required field: %q", f.Name)
+			return fmt.Errorf("%w: failed to set required field: %q", PlanError, f.Name)
 		}
 	}
 	return nil
 }
 
-func (e *env) match(dest Test) *env {
+func (e *env) match(dest Test) (*env, error) {
 	destV := reflect.ValueOf(dest).Elem()
 	destT := destV.Type()
 
 	required := getMatchFields(destT)
 	if len(required) == 0 {
-		return e
+		return e, nil
 	}
 
-	var last *env
+	var (
-	var leaf *env
+		last                  *env
+		leaf                  *env
+		foundWithWrongType    = make(map[string]bool)
+		foundWithMatchingType = make(map[string]bool)
+		foundWithWrongValue   = make(map[string]bool)
+		foundWithCorrectValue = make(map[string]bool)
+	)
 
 	for e := e; e != nil; e = e.parent {
 		present := make([]reflect.StructField, 0, len(required))
@@ -113,7 +119,10 @@ func (e *env) match(dest Test) *env {
 				break
 			}
 			if reflect.TypeOf(ev).AssignableTo(f.Type) {
+				foundWithMatchingType[f.Name] = true
 				present = append(present, f)
+			} else {
+				foundWithWrongType[f.Name] = true
 			}
 		}
 
@@ -125,7 +134,10 @@ func (e *env) match(dest Test) *env {
 			for _, f := range required {
 				fv := destV.FieldByName(f.Name)
 				if fv.Interface() == e.data[f.Name] {
+					foundWithCorrectValue[f.Name] = true
 					matched[f.Name] = e.data[f.Name]
+				} else {
+					foundWithWrongValue[f.Name] = true
 				}
 			}
 
@@ -156,5 +168,33 @@ func (e *env) match(dest Test) *env {
 		}
 	}
 
-	return leaf
+	if leaf == nil {
+		var notFound []string
+		for _, f := range required {
+			if !foundWithMatchingType[f.Name] && !foundWithWrongType[f.Name] {
+				notFound = append(notFound, f.Name)
+			}
+		}
+		switch len(notFound) {
+		case 0:
+			break
+		case 1:
+			return nil, fmt.Errorf("%w: missing required field: %q", PlanError, notFound[0])
+		default:
+			return nil, fmt.Errorf("%w: missing %d required fields: %s", PlanError, len(notFound), notFound)
+		}
+		for f, _ := range foundWithWrongType {
+			if !foundWithMatchingType[f] {
+				return nil, fmt.Errorf("%w: field %s was only found with unmatching types", PlanError, f)
+			}
+		}
+		for f, _ := range foundWithWrongValue {
+			if !foundWithCorrectValue[f] {
+				return nil, fmt.Errorf("%w: field %s was only found with unmatching values", RunError, f)
+			}
+		}
+		return nil, fmt.Errorf("%w: required match fields not encountered on the same layer", PlanError)
+	}
+
+	return leaf, nil
 }

env_test.go

@@ -1,9 +1,18 @@
 package tea
 
 import (
+	"errors"
 	"testing"
 )
 
+func assertErrorType(t *testing.T, err error, target error) {
+	if !errors.Is(err, target) {
+		t.Errorf("expected %v, instead saw %v", target, err)
+	} else {
+		t.Logf("found expected %v: %v", target, err)
+	}
+}
+
 func TestSave(t *testing.T) {
 	t.Run("empty begets nil", func(t *testing.T) {
 		e := mkenv(Pass)
@@ -100,7 +109,9 @@ func TestLoad(t *testing.T) {
 		}
 
 		if err := e.load(&test); err == nil {
-			t.Errorf("expected a load error but did not see one")
+			t.Fatalf("expected a load error but did not see one")
+		} else {
+			assertErrorType(t, err, PlanError)
 		}
 	})
 
@@ -138,6 +149,8 @@ func TestMatch(t *testing.T) {
 
 		if err := e.load(&test); err == nil {
 			t.Errorf("expected a load error but did not see one")
+		} else {
+			assertErrorType(t, err, PlanError)
 		}
 	})
 
@@ -158,6 +171,30 @@ func TestMatch(t *testing.T) {
 
 		if err := e.load(&test); err == nil {
 			t.Errorf("expected a load error but did not see one")
+		} else {
+			assertErrorType(t, err, RunError)
+		}
+	})
+
+	t.Run("required match field has wrong type", func(t *testing.T) {
+		e := &env{
+			data: map[string]interface{}{
+				"Foo":  5,
+				"Name": []byte("alice"),
+			},
+		}
+
+		var test struct {
+			Passing
+			Name string `tea:"match"`
+			Foo  int    `tea:"load"`
+		}
+		test.Name = "bob"
+
+		if err := e.load(&test); err == nil {
+			t.Errorf("expected a load error but did not see one")
+		} else {
+			assertErrorType(t, err, PlanError)
 		}
 	})
 
@@ -213,7 +250,7 @@ func TestMatch(t *testing.T) {
 		}
 	})
 
-	t.Run("complicated match", func(t *testing.T) {
+	t.Run("layer-skipping matches", func(t *testing.T) {
 		type connect struct {
 			Passing
 			Role string `tea:"save"`
@@ -269,7 +306,80 @@ func TestMatch(t *testing.T) {
 				t.Errorf("expected host to have ID 1, has %d instead", host.ID)
 			}
 		}
+	})
+
+	t.Run("layer-skipping matches", func(t *testing.T) {
+		type connect struct {
+			Passing
+			Role string `tea:"save"`
+			Name string `tea:"save"`
+			ID   int    `tea:"save"`
+		}
+
+		type request struct {
+			Passing
+			Role string `tea:"match"`
+			Name string `tea:"match"`
+			ID   int    `tea:"load"`
+			body string
+		}
 
+		e := mkenv(connect{
+			Role: "host",
+			ID:   1,
+		})
+		e = e.save(request{
+			Role: "host",
+			body: "one",
+		})
+		e = e.save(connect{
+			Role: "player",
+			Name: "alice",
+			ID:   2000000,
+		})
+		e = e.save(Pass)
+		e = e.save(connect{
+			Role: "player",
+			Name: "alice",
+			ID:   2,
+		})
+		e = e.save(connect{
+			Role: "player",
+			Name: "bob",
+			ID:   3,
+		})
+		e = e.save(Pass)
+		e = e.save(request{
+			Role: "player",
+			body: "one",
+		})
+
+		bob := request{Role: "player", Name: "bob"}
+		if err := e.load(&bob); err != nil {
+			t.Errorf("failed to load bob: %s", err)
+		} else {
+			if bob.ID != 3 {
+				t.Errorf("expected bob to have ID 3, has %d instead", bob.ID)
+			}
+		}
+
+		alice := request{Role: "player", Name: "alice"}
+		if err := e.load(&alice); err != nil {
+			t.Errorf("failed to load alice: %s", err)
+		} else {
+			if alice.ID != 2 {
+				t.Errorf("expected alice to have ID 2, has %d instead", alice.ID)
+			}
+		}
+
+		host := request{Role: "host"}
+		if err := e.load(&host); err != nil {
+			t.Errorf("failed to load host: %s", err)
+		} else {
+			if host.ID != 1 {
+				t.Errorf("expected host to have ID 1, has %d instead", host.ID)
+			}
+		}
 	})
 }
 

error.go

@@ -0,0 +1,8 @@
+package tea
+
+type testError string
+
+func (e testError) Error() string { return string(e) }
+
+const PlanError = testError("test plan error")
+const RunError = testError("test run error")