feat: Add support for .tfvars file

hcl/hcl.go

@@ -75,7 +75,7 @@ func (m *Merger) mergeTokens(aTokens hclwrite.Tokens, bTokens hclwrite.Tokens) (
 // and are identified by their key, e.g.
 // key = value
 // or key = { ... }
-func (m *Merger) mergeAttrs(aAttr map[string]*hclwrite.Attribute, bAttr map[string]*hclwrite.Attribute) map[string]hclwrite.Tokens {
+func (m *Merger) mergeAttrs(aAttr map[string]*hclwrite.Attribute, bAttr map[string]*hclwrite.Attribute, outBody *hclwrite.Body) {
 	outAttr := make(map[string]hclwrite.Tokens)
 
 	for key, aValue := range aAttr {
@@ -113,7 +113,17 @@ func (m *Merger) mergeAttrs(aAttr map[string]*hclwrite.Attribute, bAttr map[stri
 		}
 	}
 
-	return outAttr
+	// sort and add attributes
+	keys := make([]string, 0, len(outAttr))
+	for key := range outAttr {
+		keys = append(keys, key)
+	}
+
+	sort.Strings(keys)
+
+	for _, key := range keys {
+		outBody.SetAttributeRaw(key, outAttr[key])
+	}
 }
 
 // objectForTokensMap is the inverse of hclwrite.TokensForObject, only merges the top level keys, but not the values of the keys.
@@ -218,33 +228,25 @@ func objectForTokensMap(tokens hclwrite.Tokens) (map[string]hclwrite.ObjectAttrT
 }
 
 // mergeFiles merges two HCL files together
+// Files are composed of a body, which contains attributes and blocks
 func (m *Merger) mergeFiles(aFile *hclwrite.File, bFile *hclwrite.File) *hclwrite.File {
 	out := hclwrite.NewFile()
-	outBlocks := m.mergeBlocks(aFile.Body().Blocks(), bFile.Body().Blocks())
 
-	lastIndex := len(outBlocks) - 1
-
-	for i, block := range outBlocks {
-		out.Body().AppendBlock(block)
-		out.Body().AppendNewline()
-
-		// append extra newline for spacing between blocks, but not at the EOF
-		if i < lastIndex {
-			out.Body().AppendNewline()
-		}
-	}
+	m.mergeAttrs(aFile.Body().Attributes(), bFile.Body().Attributes(), out.Body())
+	m.mergeBlocks(aFile.Body().Blocks(), bFile.Body().Blocks(), out.Body())
 
 	return out
 }
 
 // mergeBlocks merges two blocks together, a block is identified by its type and labels, e.g.
 // type "label" { ... }
 // or type { ... }
-func (m *Merger) mergeBlocks(aBlocks []*hclwrite.Block, bBlocks []*hclwrite.Block) []*hclwrite.Block {
+func (m *Merger) mergeBlocks(aBlocks []*hclwrite.Block, bBlocks []*hclwrite.Block, outBody *hclwrite.Body) {
 	outBlocks := make([]*hclwrite.Block, 0)
 	aBlockMap := blockToMap(aBlocks)
 	bBlockMap := blockToMap(bBlocks)
 
+	// add all blocks from a and check if they are in b
 	for _, aBlock := range aBlocks {
 		blockKey := formatBlockKey(aBlock)
 		outBlock := aBlock
@@ -254,45 +256,42 @@ func (m *Merger) mergeBlocks(aBlocks []*hclwrite.Block, bBlocks []*hclwrite.Bloc
 			// override outBlock with the new block to merge the two blocks into
 			outBlock = hclwrite.NewBlock(aBlock.Type(), aBlock.Labels())
 
-			// merge block attributes
-			outAttributes := m.mergeAttrs(aBlock.Body().Attributes(), bBlock.Body().Attributes())
-			// sort the keys to ensure consistent ordering
-			keys := make([]string, 0, len(outAttributes))
-			for key := range outAttributes {
-				keys = append(keys, key)
-			}
-
-			sort.Strings(keys)
+			// merge the attributes and blocks of the two blocks
+			m.mergeAttrs(aBlock.Body().Attributes(), bBlock.Body().Attributes(), outBlock.Body())
 
-			for _, key := range keys {
-				outBlock.Body().SetAttributeRaw(key, outAttributes[key])
+			// format the attributes
+			if len(outBody.Attributes()) > 0 {
+				outBody.AppendNewline()
 			}
 
-			// recursively merge nested blocks
-			aNestedBlocks := aBlock.Body().Blocks()
-			bNestedBlocks := bBlock.Body().Blocks()
-			outNestedBlocks := m.mergeBlocks(aNestedBlocks, bNestedBlocks)
-
-			for _, nestedBlock := range outNestedBlocks {
-				outBlock.Body().AppendNewline()
-				outBlock.Body().AppendBlock(nestedBlock)
-			}
+			// merge the nested blocks
+			m.mergeBlocks(aBlock.Body().Blocks(), bBlock.Body().Blocks(), outBlock.Body())
 		}
 
 		outBlocks = append(outBlocks, outBlock)
 	}
 
+	// add all blocks from b that are not found in a
 	for _, bBlock := range bBlocks {
 		blockKey := formatBlockKey(bBlock)
 		_, found := aBlockMap[blockKey]
 
 		if !found {
-			// append any target blocks that were not in the source
 			outBlocks = append(outBlocks, bBlock)
 		}
 	}
 
-	return outBlocks
+	// formatting of the body
+	lastIndex := len(outBlocks) - 1
+
+	for i, block := range outBlocks {
+		outBody.AppendBlock(block)
+
+		// append extra newline for spacing between blocks, but not at the EOF
+		if i < lastIndex {
+			outBody.AppendNewline()
+		}
+	}
 }
 
 func parseBytes(bytes []byte) (*hclwrite.File, error) {

hcl/hcl_test.go

@@ -26,6 +26,18 @@ func TestMerge(t *testing.T) {
 		want    string
 		wantErr error
 	}{
+		{
+			name: "merge simple key values",
+			input: input{
+				a: `foo = "bar"
+some_value = 10
+`,
+				b: `foo = "baz"`,
+			},
+			want: `foo        = "baz"
+some_value = 10
+`,
+		},
 		{
 			name: "merge simple",
 			input: input{
@@ -45,13 +57,11 @@ func TestMerge(t *testing.T) {
   description = "Variable A"
   default     = "a"
 }
-
 variable "b" {
   type        = string
   description = "Variable B"
   default     = "b"
-}
-`,
+}`,
 			wantErr: nil,
 		},
 		{
@@ -77,7 +87,6 @@ variable "b" {
   override    = true
   type        = string
 }
-
 `,
 			wantErr: nil,
 		},
@@ -110,7 +119,6 @@ variable "b" {
     warning  = 80
   }
 }
-
 `,
 			wantErr: nil,
 		},
@@ -149,7 +157,6 @@ variable "b" {
     }
   }
 }
-
 `,
 		},
 		{
@@ -229,7 +236,6 @@ variable "b" {
     var_key      = var.value
   }
 }
-
 `,
 		},
 	}

src/hcl.test.ts

@@ -5,6 +5,15 @@
 import { merge } from "./hcl";
 
 describe("merge", () => {
+  it("should merge simple key values", async () => {
+    const a = `foo = "bar"`;
+    const b = `foo = "baz"`;
+
+    const expected = `foo = "baz"
+`;
+    const actual = await merge(a, b);
+    expect(actual).toBe(expected);
+  });
   it("should merge two hcl strings", async () => {
     const a = `variable "a" {
   type        = string
@@ -22,13 +31,11 @@ describe("merge", () => {
   description = "Variable A"
   default     = "a"
 }
-
 variable "b" {
   type        = string
   description = "Variable B"
   default     = "b"
-}
-`;
+}`;
 
     const out = await merge(a, b);
     expect(out).toBe(expected);
@@ -46,8 +53,7 @@ variable "b" {
   type        = string
   description = "Variable B"
   default     = "b"
-}
-`;
+}`;
 
     const actual = await merge(a, b);
     expect(actual).toBe(expected);
@@ -122,7 +128,6 @@ variable "b" {
     },
   }
 }
-
 `;
     const options = { mergeMapKeys: true };
     const actual = await merge(a, b, options);