Add component registry source resolution support to Terraform Stacks

internal/stacks/stackconfig/config.go

@@ -391,6 +391,17 @@
 		}
 		finalRel := rel.Versioned(selectedVersion)
 		return sourceaddrs.ResolveRelativeFinalSource(base, finalRel)
+
+	case sourceaddrs.ComponentSource:
+		// Component registry sources work similar to module registry sources
+		allowedVersions := versions.MeetingConstraints(versionConstraints)
+		availableVersions := sources.ComponentPackageVersions(rel.Package())
+		selectedVersion := availableVersions.NewestInSet(allowedVersions)
+		if selectedVersion == versions.Unspecified {
+			return nil, fmt.Errorf("no cached versions of %s match the given version constraints", rel.Package())
+		}
+		finalRel := rel.Versioned(selectedVersion)
+		return sourceaddrs.ResolveRelativeFinalSource(base, finalRel)
 	default:
 		// Should not get here because the above cases should be exhaustive
 		// for all implementations of sourceaddrs.Source.

internal/stacks/stackconfig/config_test.go

@@ -284,3 +284,85 @@ func TestOmittingBuiltInProviders(t *testing.T) {
 		})
 	})
 }
+
+func TestComponentSourceResolution(t *testing.T) {
+	bundle, err := sourcebundle.OpenDir("testdata/basics-bundle")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	rootAddr := sourceaddrs.MustParseSource("git::https://example.com/component-test.git").(sourceaddrs.RemoteSource)
+	config, diags := LoadConfigDir(rootAddr, bundle)
+	if len(diags) != 0 {
+		t.Fatalf("unexpected diagnostics:\n%s", diags.NonFatalErr().Error())
+	}
+
+	t.Run("component source resolution", func(t *testing.T) {
+		// Verify that the component was loaded
+		if got, want := len(config.Root.Stack.Components), 1; got != want {
+			t.Errorf("wrong number of components %d; want %d", got, want)
+		}
+
+		t.Run("pet-nulls component", func(t *testing.T) {
+			cmpn, ok := config.Root.Stack.Components["pet-nulls"]
+			if !ok {
+				t.Fatal("Root stack config has no component named \"pet-nulls\".")
+			}
+
+			// Verify component name
+			if got, want := cmpn.Name, "pet-nulls"; got != want {
+				t.Errorf("wrong component name\ngot:  %s\nwant: %s", got, want)
+			}
+
+			// Verify that the source address was parsed correctly
+			componentSource, ok := cmpn.SourceAddr.(sourceaddrs.ComponentSource)
+			if !ok {
+				t.Fatalf("expected ComponentSource, got %T", cmpn.SourceAddr)
+			}
+
+			expectedSourceStr := "app.staging.terraform.io/component-configurations/pet-nulls"
+			if got := componentSource.String(); got != expectedSourceStr {
+				t.Errorf("wrong source address\ngot:  %s\nwant: %s", got, expectedSourceStr)
+			}
+
+			// Verify that version constraints were parsed
+			if cmpn.VersionConstraints == nil {
+				t.Fatal("component has no version constraints")
+			}
+
+			// Verify that the final source address was resolved
+			if cmpn.FinalSourceAddr == nil {
+				t.Fatal("component FinalSourceAddr was not resolved")
+			}
+
+			// The final source should be a ComponentSourceFinal
+			componentSourceFinal, ok := cmpn.FinalSourceAddr.(sourceaddrs.ComponentSourceFinal)
+			if !ok {
+				t.Fatalf("expected ComponentSourceFinal for FinalSourceAddr, got %T", cmpn.FinalSourceAddr)
+			}
+
+			// Verify it resolved to the correct version (0.0.2)
+			expectedVersion := "0.0.2"
+			if got := componentSourceFinal.SelectedVersion().String(); got != expectedVersion {
+				t.Errorf("wrong selected version\ngot:  %s\nwant: %s", got, expectedVersion)
+			}
+
+			// Verify the unversioned component source matches
+			if got := componentSourceFinal.Unversioned().String(); got != expectedSourceStr {
+				t.Errorf("wrong unversioned source in final address\ngot:  %s\nwant: %s", got, expectedSourceStr)
+			}
+
+			// Verify we can get the local path from the bundle
+			localPath, err := bundle.LocalPathForSource(cmpn.FinalSourceAddr)
+			if err != nil {
+				t.Fatalf("failed to get local path for component source: %s", err)
+			}
+
+			// The local path should point to the pet-nulls directory
+			if localPath == "" {
+				t.Error("local path is empty")
+			}
+			t.Logf("Component resolved to local path: %s", localPath)
+		})
+	})
+}

internal/stacks/stackconfig/testdata/basics-bundle/component-test/main.tfcomponent.hcl

@@ -0,0 +1,9 @@
+component "pet-nulls" {
+  source  = "app.staging.terraform.io/component-configurations/pet-nulls"
+  version = "0.0.2"
+
+  inputs = {
+    instances = var.instances
+    prefix    = var.prefix
+  }
+}

internal/stacks/stackconfig/testdata/basics-bundle/component-test/variables.tfcomponent.hcl

@@ -0,0 +1,7 @@
+variable "instances" {
+  type = number
+}
+
+variable "prefix" {
+  type = string
+}

internal/stacks/stackconfig/testdata/basics-bundle/pet-nulls/main.tf

@@ -0,0 +1,15 @@
+variable "instances" {
+  type = number
+}
+
+variable "prefix" {
+  type = string
+}
+
+resource "null_resource" "pet" {
+  count = var.instances
+}
+
+output "pet_ids" {
+  value = null_resource.pet[*].id
+}

internal/stacks/stackconfig/testdata/basics-bundle/terraform-sources.json

@@ -30,6 +30,16 @@
             "source": "git::https://example.com/builtin.git",
             "local": "builtin",
             "meta": {}
+        },
+        {
+            "source": "git::https://example.com/component-test.git",
+            "local": "component-test",
+            "meta": {}
+        },
+        {
+            "source": "git::https://example.com/pet-nulls.git?ref=v0.0.2",
+            "local": "pet-nulls",
+            "meta": {}
         }
     ],
     "registry": [
@@ -44,5 +54,18 @@
                 }
             }
         }
+    ],
+    "components": [
+        {
+            "source": "app.staging.terraform.io/component-configurations/pet-nulls",
+            "versions": {
+                "0.0.1": {
+                    "source": "git::https://example.com/pet-nulls.git?ref=v0.0.1"
+                },
+                "0.0.2": {
+                    "source": "git::https://example.com/pet-nulls.git?ref=v0.0.2"
+                }
+            }
+        }
     ]
 }