Fixes #1123

pkg/yqlib/candidate_node.go

@@ -124,7 +124,9 @@ func (n *CandidateNode) Copy() (*CandidateNode, error) {
 func (n *CandidateNode) UpdateFrom(other *CandidateNode, prefs assignPreferences) {
 
 	// if this is an empty map or empty array, use the style of other node.
-	if n.Node.Kind != yaml.ScalarNode && len(n.Node.Content) == 0 {
+	if (n.Node.Kind != yaml.ScalarNode && len(n.Node.Content) == 0) ||
+		// if the tag has changed (e.g. from str to bool)
+		(guessTagFromCustomType(n.Node) != guessTagFromCustomType(other.Node)) {
 		n.Node.Style = other.Node.Style
 	}
 

pkg/yqlib/operator_assign_test.go

@@ -37,6 +37,33 @@ var assignOperatorScenarios = []expressionScenario{
 			"D0, P[], (doc)::a:\n    - cat\n",
 		},
 	},
+	{
+		skipDoc:     true,
+		description: "change to number when old value is valid number",
+		document:    `a: "3"`,
+		expression:  `.a = 3`,
+		expected: []string{
+			"D0, P[], (doc)::a: 3\n",
+		},
+	},
+	{
+		skipDoc:     true,
+		description: "change to bool when old value is valid bool",
+		document:    `a: "true"`,
+		expression:  `.a = true`,
+		expected: []string{
+			"D0, P[], (doc)::a: true\n",
+		},
+	},
+	{
+		skipDoc:     true,
+		description: "update custom tag string, dont clobber style",
+		document:    `a: !cat "meow"`,
+		expression:  `.a = "woof"`,
+		expected: []string{
+			"D0, P[], (doc)::a: !cat \"woof\"\n",
+		},
+	},
 	{
 		description: "Update node to be the child value",
 		document:    `{a: {b: {g: foof}}}`,