feat(engine): add pair value container and key-name affinity matching

internal/engine/bottom-up.go

@@ -183,22 +183,6 @@ func candidate(
 	return best
 }
 
-func getKeyLabel(n *treesitter.ASTNode) string {
-	if n == nil || len(n.Children) == 0 {
-		return ""
-	}
-	k := n.Children[0]
-	if k.Label != "" {
-		return k.Label
-	}
-	for _, desc := range k.Descendants() {
-		if desc.Label != "" {
-			return desc.Label
-		}
-	}
-	return ""
-}
-
 // labelOverlap returns the number of shared leaf labels in t2's subtree.
 func labelOverlap(t1Labels map[string]int, t2 *treesitter.ASTNode) int {
 	count := 0

internal/engine/matcher.go

@@ -24,6 +24,7 @@ func Match(t1, t2 *treesitter.ASTNode, srcA, srcB []byte) *MatchResult {
 	// Match AST nodes top-down, by declaration, and bottom-up using line partitioning.
 	TopDown(t1, t2, minHeight, mappings, part)
 	matchDeclarations(t1, t2, mappings)
+	matchPairValues(t1, t2, mappings)
 	BottomUp(t1, t2, mappings, minDice)
 	ContestContainers(t1, t2, mappings)
 
@@ -346,3 +347,74 @@ func getReceiverTypeName(n *treesitter.ASTNode) string {
 	}
 	return ""
 }
+
+func getParentPairKey(n *treesitter.ASTNode) string {
+	for curr := n.Parent; curr != nil; curr = curr.Parent {
+		if label := getKeyLabel(curr.Parent); label != "" {
+			return label
+		}
+	}
+	return ""
+}
+
+func matchPairValues(t1, t2 *treesitter.ASTNode, m *Mapping) {
+	if t1 == nil || t1.Language == "" {
+		return
+	}
+	r := treesitter.GetRules(t1.Language)
+	if r == nil || len(r.Pairs) == 0 {
+		return
+	}
+
+	for _, n1 := range t1.PostOrder() {
+		if !slices.Contains(r.Pairs, n1.Type) {
+			continue
+		}
+
+		var n2 *treesitter.ASTNode
+		if m.Has(n1) {
+			n2 = m.Src()[n1]
+			if n2 == nil || !slices.Contains(r.Pairs, n2.Type) {
+				continue
+			}
+		} else {
+			key1 := getKeyLabel(n1)
+			if key1 == "" {
+				continue
+			}
+			anc1 := NearestMatchedAncestor(n1, m, false)
+			pKey1 := getParentPairKey(n1)
+
+			for _, cand := range t2.PostOrder() {
+				if !slices.Contains(r.Pairs, cand.Type) || m.HasDst(cand) {
+					continue
+				}
+				if getKeyLabel(cand) != key1 {
+					continue
+				}
+				anc2 := NearestMatchedAncestor(cand, m, true)
+				if !areAncestorsMatched(anc1, anc2, m) {
+					continue
+				}
+
+				pKey2 := getParentPairKey(cand)
+				if pKey1 != pKey2 {
+					continue
+				}
+
+				n2 = cand
+				m.Add(n1, n2)
+				m.Add(n1.Children[0], n2.Children[0])
+				break
+			}
+		}
+
+		if n2 != nil && len(n1.Children) >= 2 && len(n2.Children) >= 2 {
+			val1 := n1.Children[len(n1.Children)-1]
+			val2 := n2.Children[len(n2.Children)-1]
+			if !m.Has(val1) && !m.HasDst(val2) && len(val1.Children) > 0 && len(val2.Children) > 0 && val1.Type == val2.Type {
+				m.Add(val1, val2)
+			}
+		}
+	}
+}

internal/engine/matcher_test.go

@@ -243,3 +243,54 @@ func TestMatchUnmatchedLeavesIgnoresKeywords(t *testing.T) {
 		t.Errorf("MatchContainerKeywords should map kw1 to kw2 under mapped parents, got %v", m.Src()[kw1])
 	}
 }
+
+func TestMatchPairValues(t *testing.T) {
+	k1 := testutil.Leaf("string", "\"priority\"")
+	val1 := testutil.Node("object", "", testutil.Leaf("string", "\"a\""))
+	p1 := testutil.Node("key_value_pair", "", k1, val1)
+	srcRoot := testutil.Node("root", "", p1)
+	srcRoot.Language = "go"
+
+	k2 := testutil.Leaf("string", "\"priority\"")
+	val2 := testutil.Node("object", "", testutil.Leaf("string", "\"b\""))
+	p2 := testutil.Node("key_value_pair", "", k2, val2)
+	dstRoot := testutil.Node("root", "", p2)
+
+	m := NewMapping()
+	m.Add(p1, p2)
+
+	matchPairValues(srcRoot, dstRoot, m)
+
+	if !m.Has(val1) || m.Src()[val1] != val2 {
+		t.Errorf("matchPairValues should map val1 to val2, got %v", m.Src()[val1])
+	}
+}
+
+func TestMatchPairKeyNameAffinity(t *testing.T) {
+	// Old pair: "priority": { ... }
+	kOld := testutil.Leaf("string", "\"priority\"")
+	valOld := testutil.Node("object", "")
+	pairOld := testutil.Node("pair", "", kOld, valOld)
+	srcObj := testutil.Node("object", "", pairOld)
+
+	// New pair 1: "priority": { ... }
+	kNew1 := testutil.Leaf("string", "\"priority\"")
+	valNew1 := testutil.Node("object", "")
+	pairNew1 := testutil.Node("pair", "", kNew1, valNew1)
+
+	// New pair 2: "oneOf": [ ... ]
+	kNew2 := testutil.Leaf("string", "\"oneOf\"")
+	valNew2 := testutil.Node("array", "")
+	pairNew2 := testutil.Node("pair", "", kNew2, valNew2)
+
+	dstObj := testutil.Node("object", "", pairNew1, pairNew2)
+
+	r := Match(srcObj, dstObj, nil, nil)
+	if r == nil || r.Mappings == nil {
+		t.Fatal("Match returned nil")
+	}
+
+	if r.Mappings.Src()[pairOld] != pairNew1 {
+		t.Errorf("pairOld ('priority') should match pairNew1 ('priority'), got %v", r.Mappings.Src()[pairOld])
+	}
+}

internal/engine/utils.go

@@ -48,6 +48,22 @@ func descendantSet(n *treesitter.ASTNode) map[*treesitter.ASTNode]struct{} {
 	return s
 }
 
+func getKeyLabel(n *treesitter.ASTNode) string {
+	if n == nil || len(n.Children) == 0 {
+		return ""
+	}
+	k := n.Children[0]
+	if k.Label != "" {
+		return k.Label
+	}
+	for _, desc := range k.Descendants() {
+		if desc.Label != "" {
+			return desc.Label
+		}
+	}
+	return ""
+}
+
 func commonMappedDescendants(t1, t2 *treesitter.ASTNode, m map[*treesitter.ASTNode]*treesitter.ASTNode) (common, lenS1, lenS2 int) {
 	s1 := t1.Descendants()
 	s2 := descendantSet(t2)

internal/treesitter/c/rules.yml

@@ -156,4 +156,6 @@ declarations:
   - parameter_declaration
   - field_declaration
 
-
+pairs:
+  - field_designator
+  - initializer_pair

internal/treesitter/cpp/rules.yml

@@ -209,4 +209,6 @@ declarations:
   - parameter_declaration
   - field_declaration
 
-
+pairs:
+  - field_designator
+  - initializer_pair

internal/treesitter/go/rules.yml

@@ -127,5 +127,7 @@ declarations:
 unordered:
   - interface_type
 
-
+pairs:
+  - key_value_pair
+  - keyed_element
 

internal/treesitter/java/rules.yml

@@ -190,5 +190,6 @@ declarations:
 unordered:
   - annotation
 
-
+pairs:
+  - element_value_pair
 

internal/treesitter/javascript/rules.yml

@@ -177,6 +177,8 @@ unordered:
   - object
   - object_pattern
 
-
-
+pairs:
+  - pair
+  - property_assignment
+  - pair_pattern
 

internal/treesitter/json/rules.yml

@@ -22,3 +22,6 @@ keywords:
   - "true"
   - "false"
   - "null"
+
+pairs:
+  - pair

internal/treesitter/lua/rules.yml

@@ -110,3 +110,5 @@ declarations:
   - function_definition
   - variable_declaration
 
+pairs:
+  - field

internal/treesitter/php/rules.yml

@@ -176,3 +176,7 @@ unordered:
   - attribute_group
   - attribute_list
 
+pairs:
+  - pair
+  - array_element_initializer
+

internal/treesitter/python/rules.yml

@@ -159,5 +159,7 @@ unordered:
   - dictionary
   - set
 
-
+pairs:
+  - pair
+  - keyword_argument
 

internal/treesitter/ruby/rules.yml

@@ -159,5 +159,6 @@ unordered:
   - hash
   - hash_pattern
 
-
+pairs:
+  - pair
 

internal/treesitter/rules.go

@@ -16,6 +16,7 @@ type Rules struct {
 	Scaffolding  []string          `yaml:"scaffolding"`
 	Keywords     []string          `yaml:"keywords"`
 	Declarations []string          `yaml:"declarations"`
+	Pairs        []string          `yaml:"pairs"`
 	Unordered    []string          `yaml:"unordered"`
 }
 

internal/treesitter/rules_test.go

@@ -194,3 +194,15 @@ func TestRulesUnordered(t *testing.T) {
 		t.Errorf("unexpected unordered entries: %v", r.Unordered)
 	}
 }
+
+func TestRulesPairs(t *testing.T) {
+	r := &Rules{
+		Pairs: []string{"pair", "key_value_pair"},
+	}
+	if len(r.Pairs) != 2 {
+		t.Fatalf("expected 2 pairs entries, got %d", len(r.Pairs))
+	}
+	if r.Pairs[0] != "pair" || r.Pairs[1] != "key_value_pair" {
+		t.Errorf("unexpected pairs entries: %v", r.Pairs)
+	}
+}

internal/treesitter/rust/rules.yml

@@ -154,5 +154,7 @@ declarations:
 unordered:
   - use_declaration
 
-
+pairs:
+  - field_initializer
+  - struct_pattern_field
 

internal/treesitter/tsx/rules.yml

@@ -197,6 +197,10 @@ unordered:
   - jsx_self_closing_element
   - object_pattern
 
-
-
+pairs:
+  - pair
+  - property_assignment
+  - pair_pattern
+  - property_signature
+  - jsx_attribute
 

internal/treesitter/typescript/rules.yml

@@ -181,6 +181,9 @@ unordered:
   - object_type
   - object_pattern
 
-
-
+pairs:
+  - pair
+  - property_assignment
+  - pair_pattern
+  - property_signature
 

internal/treesitter/zig/rules.yml

@@ -131,4 +131,6 @@ declarations:
   - test_declaration
   - using_namespace_declaration
 
-
+pairs:
+  - initializer_pair
+  - field_initializer