From 8855bb18a04462a4ea32c73f468af092432a813f Mon Sep 17 00:00:00 2001
From: CrazyMax <crazy-max@users.noreply.github.com>
Date: Tue, 5 Apr 2022 16:08:56 +0200
Subject: [PATCH] bake: merge vars from multiple JSON files

Signed-off-by: CrazyMax <crazy-max@users.noreply.github.com>
---
 bake/hcl_test.go            | 49 +++++++++++++++++++++++++++++++++++++
 bake/hclparser/hclparser.go | 10 ++++++--
 2 files changed, 57 insertions(+), 2 deletions(-)

diff --git a/bake/hcl_test.go b/bake/hcl_test.go
index 20131deed989..42398c4a4935 100644
--- a/bake/hcl_test.go
+++ b/bake/hcl_test.go
@@ -696,3 +696,52 @@ target "b" {
 	require.Equal(t, ".", *c.Targets[3].Context)
 	require.Equal(t, "b", *c.Targets[3].Target)
 }
+
+func TestCombineHCLAndJSONWithGlobalAttrs(t *testing.T) {
+	c, err := ParseFiles([]File{
+		{
+			Name: "docker-bake.hcl",
+			Data: []byte(`
+variable "ABC" {
+  default = "foo"
+}
+variable "DEF" {
+  default = ""
+}
+group "default" {
+  targets = ["one"]
+}
+target "one" {
+  args = {
+    a = "pre-${ABC}"
+  }
+}
+target "two" {
+  args = {
+    b = "pre-${DEF}"
+  }
+}`),
+		},
+		{
+			Name: "foo.json",
+			Data: []byte(`{"variable": {"DEF": {"default": "bar"}}, "target": { "one": { "args": {"a": "pre-${ABC}-${DEF}"}} } }`),
+		},
+		{
+			Name: "bar.json",
+			Data: []byte(`{"ABC": "ghi", "DEF": "jkl"}`),
+		},
+	}, nil)
+	require.NoError(t, err)
+
+	require.Equal(t, 1, len(c.Groups))
+	require.Equal(t, "default", c.Groups[0].Name)
+	require.Equal(t, []string{"one"}, c.Groups[0].Targets)
+
+	require.Equal(t, 2, len(c.Targets))
+
+	require.Equal(t, c.Targets[0].Name, "one")
+	require.Equal(t, map[string]string{"a": "pre-ghi-jkl"}, c.Targets[0].Args)
+
+	require.Equal(t, c.Targets[1].Name, "two")
+	require.Equal(t, map[string]string{"b": "pre-jkl"}, c.Targets[1].Args)
+}
diff --git a/bake/hclparser/hclparser.go b/bake/hclparser/hclparser.go
index c4bbf1fb8411..233d6557d885 100644
--- a/bake/hclparser/hclparser.go
+++ b/bake/hclparser/hclparser.go
@@ -302,7 +302,7 @@ func Parse(b hcl.Body, opt Opt, val interface{}) hcl.Diagnostics {
 
 	attrs, diags := b.JustAttributes()
 	if diags.HasErrors() {
-		if d := removeAttributesDiags(diags, reserved); len(d) > 0 {
+		if d := removeAttributesDiags(diags, reserved, p.vars); len(d) > 0 {
 			return d
 		}
 	}
@@ -513,7 +513,7 @@ func setLabel(v reflect.Value, lbl string) int {
 	return -1
 }
 
-func removeAttributesDiags(diags hcl.Diagnostics, reserved map[string]struct{}) hcl.Diagnostics {
+func removeAttributesDiags(diags hcl.Diagnostics, reserved map[string]struct{}, vars map[string]*variable) hcl.Diagnostics {
 	var fdiags hcl.Diagnostics
 	for _, d := range diags {
 		if fout := func(d *hcl.Diagnostic) bool {
@@ -529,6 +529,12 @@ func removeAttributesDiags(diags hcl.Diagnostics, reserved map[string]struct{})
 					return true
 				}
 			}
+			for v := range vars {
+				// Do the same for global variables
+				if strings.HasPrefix(d.Detail, fmt.Sprintf(`Argument "%s" was already set at `, v)) {
+					return true
+				}
+			}
 			return false
 		}(d); !fout {
 			fdiags = append(fdiags, d)