From 6270c29f546259b9d5e8957cc49c49179a0a7dc4 Mon Sep 17 00:00:00 2001
From: Mike Farah <mikefarah@gmail.com>
Date: Sun, 7 Dec 2025 20:26:01 +1100
Subject: [PATCH] Fixed processing of nested data

---
 pkg/yqlib/decoder_hcl.go | 29 ++++++++++++++---------------
 pkg/yqlib/hcl_test.go    | 14 +++++++++++++-
 2 files changed, 27 insertions(+), 16 deletions(-)

diff --git a/pkg/yqlib/decoder_hcl.go b/pkg/yqlib/decoder_hcl.go
index bf54c8ac..597eb5c9 100644
--- a/pkg/yqlib/decoder_hcl.go
+++ b/pkg/yqlib/decoder_hcl.go
@@ -81,14 +81,7 @@ func (dec *hclDecoder) Decode() (*CandidateNode, error) {
 
 	// process blocks
 	for _, block := range body.Blocks {
-		// build a key from type and labels to preserve identity
-		keyName := block.Type
-		if len(block.Labels) > 0 {
-			keyName = keyName + " " + strings.Join(block.Labels, " ")
-		}
-		keyNode := createStringScalarNode(keyName)
-		valueNode := hclBodyToNode(block.Body, dec.fileBytes)
-		root.AddKeyValueChild(keyNode, valueNode)
+		addBlockToMapping(root, block, dec.fileBytes)
 	}
 
 	dec.documentIndex++
@@ -104,17 +97,23 @@ func hclBodyToNode(body *hclsyntax.Body, src []byte) *CandidateNode {
 		node.AddKeyValueChild(key, val)
 	}
 	for _, block := range body.Blocks {
-		keyName := block.Type
-		if len(block.Labels) > 0 {
-			keyName = keyName + " " + strings.Join(block.Labels, " ")
-		}
-		key := createStringScalarNode(keyName)
-		val := hclBodyToNode(block.Body, src)
-		node.AddKeyValueChild(key, val)
+		addBlockToMapping(node, block, src)
 	}
 	return node
 }
 
+// addBlockToMapping nests block type and labels into the parent mapping, merging children.
+func addBlockToMapping(parent *CandidateNode, block *hclsyntax.Block, src []byte) {
+	bodyNode := hclBodyToNode(block.Body, src)
+	chain := bodyNode
+	for i := len(block.Labels) - 1; i >= 0; i-- {
+		wrap := &CandidateNode{Kind: MappingNode}
+		wrap.AddKeyValueChild(createStringScalarNode(block.Labels[i]), chain)
+		chain = wrap
+	}
+	parent.AddKeyValueChild(createStringScalarNode(block.Type), chain)
+}
+
 func convertHclExprToNode(expr hclsyntax.Expression, src []byte) *CandidateNode {
 	// handle literal values directly
 	switch e := expr.(type) {
diff --git a/pkg/yqlib/hcl_test.go b/pkg/yqlib/hcl_test.go
index 41c43956..6bf377e5 100644
--- a/pkg/yqlib/hcl_test.go
+++ b/pkg/yqlib/hcl_test.go
@@ -6,6 +6,12 @@ import (
 	"github.com/mikefarah/yq/v4/test"
 )
 
+var nestedExample = `service "http" "web_proxy" {
+  listen_addr = "127.0.0.1:8080"
+}`
+
+var nestedExampleYaml = "service:\n  http:\n    web_proxy:\n      listen_addr: \"127.0.0.1:8080\"\n"
+
 var hclFormatScenarios = []formatScenario{
 	{
 		description:  "Simple decode",
@@ -25,6 +31,12 @@ var hclFormatScenarios = []formatScenario{
 		expected:     "io_mode = async\n",
 		scenarioType: "roundtrip",
 	},
+	{
+		description:  "Nested decode",
+		input:        nestedExample,
+		expected:     nestedExampleYaml,
+		scenarioType: "decode",
+	},
 	{
 		description:  "Template decode",
 		input:        `message = "Hello, ${name}!"`,
@@ -124,7 +136,7 @@ var hclFormatScenarios = []formatScenario{
 	{
 		description:  "block with labels",
 		input:        `resource "aws_instance" "example" { ami = "ami-12345" }`,
-		expected:     "resource aws_instance example:\n  ami: \"ami-12345\"\n",
+		expected:     "resource:\n  aws_instance:\n    example:\n      ami: \"ami-12345\"\n",
 		scenarioType: "decode",
 	},
 	{