Parse bake config as hcl falling back to json

Signed-off-by: Patrick Van Stee <patrick@vanstee.me>

bake/hcl.go

@@ -74,18 +74,20 @@ type staticConfig struct {
 }
 
 func ParseHCL(dt []byte, fn string) (*Config, error) {
-	var file *hcl.File
-	var diags hcl.Diagnostics
-
-	// Decode user defined functions.
-	fnl := strings.ToLower(fn)
-	if strings.HasSuffix(fnl, ".json") {
-		file, diags = json.Parse(dt, fn)
-	} else {
-		file, diags = hclsyntax.ParseConfig(dt, fn, hcl.Pos{Line: 1, Column: 1})
-	}
-	if diags.HasErrors() {
-		return nil, diags
+	// Decode user defined functions, first parsing as hcl and falling back to
+	// json, returning errors based on the file suffix.
+	file, hcldiags := hclsyntax.ParseConfig(dt, fn, hcl.Pos{Line: 1, Column: 1})
+	if hcldiags.HasErrors() {
+		var jsondiags hcl.Diagnostics
+		file, jsondiags = json.Parse(dt, fn)
+		if jsondiags.HasErrors() {
+			fnl := strings.ToLower(fn)
+			if strings.HasSuffix(fnl, ".json") {
+				return nil, jsondiags
+			} else {
+				return nil, hcldiags
+			}
+		}
 	}
 
 	userFunctions, _, diags := userfunc.DecodeUserFunctions(file.Body, "function", func() *hcl.EvalContext {