command: Providers schema shows required_providers

command/testdata/providers-schema/required/output.json

@@ -0,0 +1,41 @@
+{
+    "format_version": "0.1",
+    "provider_schemas": {
+        "registry.terraform.io/hashicorp/test": {
+            "provider": {
+                "version": 0,
+                "block": {
+                    "attributes": {
+                        "region": {
+                            "description_kind": "plain",
+                            "optional": true,
+                            "type": "string"
+                        }
+                    },
+                    "description_kind": "plain"
+                }
+            },
+            "resource_schemas": {
+                "test_instance": {
+                    "version": 0,
+                    "block": {
+                        "attributes": {
+                            "ami": {
+                                "type": "string",
+                                "optional": true,
+                                "description_kind": "plain"
+                            },
+                            "id": {
+                                "type": "string",
+                                "optional": true,
+                                "computed": true,
+                                "description_kind": "plain"
+                            }
+                        },
+                        "description_kind": "plain"
+                    }
+                }
+            }
+        }
+    }
+}

command/testdata/providers-schema/required/provider.tf

@@ -0,0 +1,7 @@
+terraform {
+  required_providers {
+    test = {
+      source = "hashicorp/test"
+    }
+  }
+}

configs/config.go

@@ -226,6 +226,7 @@ func (c *Config) addProviderRequirements(reqs getproviders.Requirements, recurse
 	var diags hcl.Diagnostics
 
 	// First we'll deal with the requirements directly in _our_ module...
+	if c.Module.ProviderRequirements != nil {
 		for _, providerReqs := range c.Module.ProviderRequirements.RequiredProviders {
 			fqn := providerReqs.Type
 			if _, ok := reqs[fqn]; !ok {
@@ -253,6 +254,8 @@ func (c *Config) addProviderRequirements(reqs getproviders.Requirements, recurse
 			}
 			reqs[fqn] = append(reqs[fqn], constraints...)
 		}
+	}
+
 	// Each resource in the configuration creates an *implicit* provider
 	// dependency, though we'll only record it if there isn't already
 	// an explicit dependency on the same provider.
@@ -323,11 +326,11 @@ func (c *Config) addProviderRequirements(reqs getproviders.Requirements, recurse
 // provider version selection in an earlier step and have identified suitable
 // versions for each provider.
 func (c *Config) ProviderTypes() []addrs.Provider {
-	m := make(map[addrs.Provider]struct{})
-	c.gatherProviderTypes(m)
+	// Ignore diagnostics here because they relate to version constraints
+	reqs, _ := c.ProviderRequirements()
 
-	ret := make([]addrs.Provider, 0, len(m))
-	for k := range m {
+	ret := make([]addrs.Provider, 0, len(reqs))
+	for k := range reqs {
 		ret = append(ret, k)
 	}
 	sort.Slice(ret, func(i, j int) bool {
@@ -336,32 +339,6 @@ func (c *Config) ProviderTypes() []addrs.Provider {
 	return ret
 }
 
-func (c *Config) gatherProviderTypes(m map[addrs.Provider]struct{}) {
-	if c == nil {
-		return
-	}
-
-	for _, pc := range c.Module.ProviderConfigs {
-		fqn := c.Module.ProviderForLocalConfig(addrs.LocalProviderConfig{LocalName: pc.Name})
-		m[fqn] = struct{}{}
-	}
-	for _, rc := range c.Module.ManagedResources {
-		providerAddr := rc.ProviderConfigAddr()
-		fqn := c.Module.ProviderForLocalConfig(providerAddr)
-		m[fqn] = struct{}{}
-	}
-	for _, rc := range c.Module.DataResources {
-		providerAddr := rc.ProviderConfigAddr()
-		fqn := c.Module.ProviderForLocalConfig(providerAddr)
-		m[fqn] = struct{}{}
-	}
-
-	// Must also visit our child modules, recursively.
-	for _, cc := range c.Children {
-		cc.gatherProviderTypes(m)
-	}
-}
-
 // ResolveAbsProviderAddr returns the AbsProviderConfig represented by the given
 // ProviderConfig address, which must not be nil or this method will panic.
 //

configs/config_test.go

@@ -32,6 +32,7 @@ func TestConfigProviderTypes(t *testing.T) {
 		addrs.NewDefaultProvider("aws"),
 		addrs.NewDefaultProvider("null"),
 		addrs.NewDefaultProvider("template"),
+		addrs.NewDefaultProvider("test"),
 	}
 	for _, problem := range deep.Equal(got, want) {
 		t.Error(problem)

configs/testdata/valid-files/providers-explicit-implied.tf

@@ -13,3 +13,11 @@ resource "aws_instance" "foo" {
 resource "null_resource" "foo" {
 
 }
+
+terraform {
+  required_providers {
+    test = {
+      source = "hashicorp/test"
+    }
+  }
+}