Infer Map[string] when the Map's element type is unspecified (#2316)

SDKv2 providers allow specifying a map type without a backing element
type:

```go
schema.Schema{
	Type:     schema.TypeMap,
	Required: true,
}
```

Previously, the bridge interpreted this as `map[any]`. This does not
agree with TF's interpretation: `map[string]`. This PR changes the
bridge to correctly interpret `map[???]` as `map[string]`.

Fixes pulumi/pulumi-nomad#389

pkg/tests/internal/tfcheck/tf_test.go

@@ -54,6 +54,67 @@ resource "test_resource" "test" {
 	t.Logf(driver.GetState(t))
 }
 
+// TestTfMapMissingElem shows that maps missing Elem types are equivalent to specifying:
+//
+//	Elem: &schema.Schema{Type: schema.TypeString}
+//
+// Previously, the bridge treated a missing map element type as `schema.TypeAny` instead
+// of `schema.TypeString`, which caused provider panics. For example:
+//
+// - https://github.com/pulumi/pulumi-nomad/issues/389
+func TestTfMapMissingElem(t *testing.T) {
+	prov := schema.Provider{
+		ResourcesMap: map[string]*schema.Resource{
+			"test_resource": {
+				Schema: map[string]*schema.Schema{
+					"m": {
+						Type:     schema.TypeMap,
+						Required: true,
+					},
+				},
+				CreateContext: func(ctx context.Context, d *schema.ResourceData, _ interface{}) diag.Diagnostics {
+					var errs diag.Diagnostics
+					if _, ok := d.Get("m").(map[string]any)["string"].(string); !ok {
+						errs = append(errs, diag.Errorf(`expected m["string"] to be a string`)...)
+					}
+					if _, ok := d.Get("m").(map[string]any)["number"].(string); !ok {
+						errs = append(errs, diag.Errorf(`expected m["number"] to be a string`)...)
+					}
+
+					d.SetId("test")
+					return errs
+				},
+			},
+		},
+	}
+
+	driver := NewTfDriver(t, t.TempDir(), "test", &prov)
+
+	driver.Write(t, `
+resource "test_resource" "test" {
+  m = {
+    "string" = "123"
+    "number" =  123
+  }
+}
+`,
+	)
+
+	plan := driver.Plan(t)
+	t.Logf(driver.Show(t, plan.PlanFile))
+	driver.Apply(t, plan)
+
+	t.Logf(driver.GetState(t))
+
+	newPlan := driver.Plan(t)
+
+	t.Logf(driver.Show(t, plan.PlanFile))
+
+	driver.Apply(t, newPlan)
+
+	t.Logf(driver.GetState(t))
+}
+
 func TestTfUnknownObjects(t *testing.T) {
 	prov := schema.Provider{
 		ResourcesMap: map[string]*schema.Resource{

pkg/tfgen/generate.go

@@ -319,7 +319,7 @@ type moduleMember interface {
 type typeKind int
 
 const (
-	kindInvalid = iota
+	kindInvalid typeKind = iota
 	kindBool
 	kindInt
 	kindFloat
@@ -330,9 +330,6 @@ const (
 	kindObject
 )
 
-// Avoid an unused warning from varcheck.
-var _ = kindInvalid
-
 // propertyType represents a non-resource, non-datasource type. Property types may be simple
 type propertyType struct {
 	name       string
@@ -431,6 +428,10 @@ func (g *Generator) makePropertyType(typePath paths.TypePath,
 	switch sch.Type() {
 	case shim.TypeMap:
 		t.kind = kindMap
+		// TF treats maps without a specified type as map[string]string, so we do the same.
+		if element == nil || element.kind == kindInvalid {
+			element = &propertyType{kind: kindString}
+		}
 	case shim.TypeList:
 		t.kind = kindList
 	case shim.TypeSet:

pkg/tfgen/generate_test.go

@@ -166,7 +166,7 @@ func Test_makePropertyType(t *testing.T) {
 	t.Run("String", func(t *testing.T) {
 		p, err := g.makePropertyType(path, "obj", strType, nil, false, entityDocs{})
 		require.NoError(t, err)
-		assert.Equal(t, typeKind(kindString), p.kind)
+		assert.Equal(t, kindString, p.kind)
 	})
 
 	//TODO: change this test to assert typeKind when implementing
@@ -183,8 +183,8 @@ func Test_makePropertyType(t *testing.T) {
 		}).Shim()
 		p, err := g.makePropertyType(path, "obj", strListType, nil, false, entityDocs{})
 		require.NoError(t, err)
-		assert.Equal(t, typeKind(kindList), p.kind)
-		assert.Equal(t, typeKind(kindString), p.element.kind)
+		assert.Equal(t, kindList, p.kind)
+		assert.Equal(t, kindString, p.element.kind)
 	})
 
 	t.Run("MapString", func(t *testing.T) {
@@ -194,8 +194,8 @@ func Test_makePropertyType(t *testing.T) {
 		}).Shim()
 		p, err := g.makePropertyType(path, "obj", strMapType, nil, false, entityDocs{})
 		require.NoError(t, err)
-		assert.Equal(t, typeKind(kindMap), p.kind)
-		assert.Equal(t, typeKind(kindString), p.element.kind)
+		assert.Equal(t, kindMap, p.kind)
+		assert.Equal(t, kindString, p.element.kind)
 	})
 
 	t.Run("MapUnknown", func(t *testing.T) {
@@ -204,8 +204,8 @@ func Test_makePropertyType(t *testing.T) {
 		}).Shim()
 		p, err := g.makePropertyType(path, "obj", unkMapType, nil, false, entityDocs{})
 		require.NoError(t, err)
-		assert.Equal(t, typeKind(kindMap), p.kind)
-		assert.Nil(t, p.element)
+		assert.Equal(t, kindMap, p.kind)
+		assert.Equal(t, kindString, p.element.kind)
 	})
 
 	t.Run("SingleNestedBlock", func(t *testing.T) {
@@ -215,7 +215,7 @@ func Test_makePropertyType(t *testing.T) {
 		}).Shim()
 		p, err := g.makePropertyType(path, "obj", objType, nil, false, entityDocs{})
 		require.NoError(t, err)
-		assert.Equal(t, typeKind(kindObject), p.kind)
+		assert.Equal(t, kindObject, p.kind)
 		assert.Equal(t, "config.prop", p.properties[0].parentPath.String())
 	})
 
@@ -226,8 +226,8 @@ func Test_makePropertyType(t *testing.T) {
 		}).Shim()
 		p, err := g.makePropertyType(path, "obj", objType, nil, false, entityDocs{})
 		require.NoError(t, err)
-		assert.Equal(t, typeKind(kindList), p.kind)
-		assert.Equal(t, typeKind(kindObject), p.element.kind)
+		assert.Equal(t, kindList, p.kind)
+		assert.Equal(t, kindObject, p.element.kind)
 		assert.Equal(t, "config.prop.$", p.element.properties[0].parentPath.String())
 	})
 
@@ -239,7 +239,7 @@ func Test_makePropertyType(t *testing.T) {
 		}).Shim()
 		p, err := g.makePropertyType(path, "obj", objType, nil, false, entityDocs{})
 		require.NoError(t, err)
-		assert.Equal(t, typeKind(kindObject), p.kind)
+		assert.Equal(t, kindObject, p.kind)
 		assert.Equal(t, "config.prop", p.properties[0].parentPath.String())
 	})
 
@@ -250,8 +250,8 @@ func Test_makePropertyType(t *testing.T) {
 		}).Shim()
 		p, err := g.makePropertyType(path, "obj", objType, nil, false, entityDocs{})
 		require.NoError(t, err)
-		assert.Equal(t, typeKind(kindSet), p.kind)
-		assert.Equal(t, typeKind(kindObject), p.element.kind)
+		assert.Equal(t, kindSet, p.kind)
+		assert.Equal(t, kindObject, p.element.kind)
 		assert.Equal(t, "config.prop.$", p.element.properties[0].parentPath.String())
 	})
 
@@ -263,7 +263,7 @@ func Test_makePropertyType(t *testing.T) {
 		}).Shim()
 		p, err := g.makePropertyType(path, "obj", objType, nil, false, entityDocs{})
 		require.NoError(t, err)
-		assert.Equal(t, typeKind(kindObject), p.kind)
+		assert.Equal(t, kindObject, p.kind)
 		assert.Equal(t, "config.prop", p.properties[0].parentPath.String())
 	})
 }

pkg/tfgen/test_data/minimuxed-schema.json

@@ -49,7 +49,7 @@
         "keepers": {
           "type": "object",
           "additionalProperties": {
-            "$ref": "pulumi.json#/Any"
+            "type": "string"
           },
           "description": "Arbitrary map of values that, when changed, will trigger recreation of resource. See the main provider documentation for\nmore information.\n"
         },
@@ -79,7 +79,7 @@
         "keepers": {
           "type": "object",
           "additionalProperties": {
-            "$ref": "pulumi.json#/Any"
+            "type": "string"
           },
           "description": "Arbitrary map of values that, when changed, will trigger recreation of resource. See the main provider documentation for\nmore information.\n",
           "willReplaceOnChanges": true
@@ -110,7 +110,7 @@
           "keepers": {
             "type": "object",
             "additionalProperties": {
-              "$ref": "pulumi.json#/Any"
+              "type": "string"
             },
             "description": "Arbitrary map of values that, when changed, will trigger recreation of resource. See the main provider documentation for\nmore information.\n",
             "willReplaceOnChanges": true

pkg/tfgen/test_data/minirandom-schema-csharp.json

@@ -35,7 +35,7 @@
         "keepers": {
           "type": "object",
           "additionalProperties": {
-            "$ref": "pulumi.json#/Any"
+            "type": "string"
           },
           "description": "Arbitrary map of values that, when changed, will trigger recreation of resource. See the main provider documentation for\nmore information.\n"
         },
@@ -75,7 +75,7 @@
         "keepers": {
           "type": "object",
           "additionalProperties": {
-            "$ref": "pulumi.json#/Any"
+            "type": "string"
           },
           "description": "Arbitrary map of values that, when changed, will trigger recreation of resource. See the main provider documentation for\nmore information.\n",
           "willReplaceOnChanges": true
@@ -111,7 +111,7 @@
           "keepers": {
             "type": "object",
             "additionalProperties": {
-              "$ref": "pulumi.json#/Any"
+              "type": "string"
             },
             "description": "Arbitrary map of values that, when changed, will trigger recreation of resource. See the main provider documentation for\nmore information.\n",
             "willReplaceOnChanges": true

pkg/tfgen/test_data/regress-minirandom-schema.json

@@ -35,7 +35,7 @@
         "keepers": {
           "type": "object",
           "additionalProperties": {
-            "$ref": "pulumi.json#/Any"
+            "type": "string"
           },
           "description": "Arbitrary map of values that, when changed, will trigger recreation of resource. See the main provider documentation for\nmore information.\n"
         },
@@ -65,7 +65,7 @@
         "keepers": {
           "type": "object",
           "additionalProperties": {
-            "$ref": "pulumi.json#/Any"
+            "type": "string"
           },
           "description": "Arbitrary map of values that, when changed, will trigger recreation of resource. See the main provider documentation for\nmore information.\n",
           "willReplaceOnChanges": true
@@ -96,7 +96,7 @@
           "keepers": {
             "type": "object",
             "additionalProperties": {
-              "$ref": "pulumi.json#/Any"
+              "type": "string"
             },
             "description": "Arbitrary map of values that, when changed, will trigger recreation of resource. See the main provider documentation for\nmore information.\n",
             "willReplaceOnChanges": true

pkg/tfgen/test_data/test-propagate-language-options.json

@@ -52,7 +52,7 @@
         "keepers": {
           "type": "object",
           "additionalProperties": {
-            "$ref": "pulumi.json#/Any"
+            "type": "string"
           },
           "description": "Arbitrary map of values that, when changed, will trigger recreation of resource. See the main provider documentation for\nmore information.\n"
         },
@@ -82,7 +82,7 @@
         "keepers": {
           "type": "object",
           "additionalProperties": {
-            "$ref": "pulumi.json#/Any"
+            "type": "string"
           },
           "description": "Arbitrary map of values that, when changed, will trigger recreation of resource. See the main provider documentation for\nmore information.\n",
           "willReplaceOnChanges": true
@@ -113,7 +113,7 @@
           "keepers": {
             "type": "object",
             "additionalProperties": {
-              "$ref": "pulumi.json#/Any"
+              "type": "string"
             },
             "description": "Arbitrary map of values that, when changed, will trigger recreation of resource. See the main provider documentation for\nmore information.\n",
             "willReplaceOnChanges": true