addrs: Simplify presentation of provider FQNs

The provider fully-qualified name string used in configuration is very
long, and since most providers are hosted in the public registry, most
of that length is redundant. This commit adds and uses a `ForDisplay`
method, which simplifies the presentation of provider FQNs.

If the hostname is the default hostname, we now display only the
namespace and type. This is only used in UI, but should still be
unambiguous, as it matches the FQN string parsing behaviour.

addrs/provider.go

@@ -44,7 +44,7 @@ const BuiltInProviderNamespace = "builtin"
 // FQN.
 const LegacyProviderNamespace = "-"
 
-// String returns an FQN string, indended for use in output.
+// String returns an FQN string, indended for use in machine-readable output.
 func (pt Provider) String() string {
 	if pt.IsZero() {
 		panic("called String on zero-value addrs.Provider")
@@ -52,6 +52,19 @@ func (pt Provider) String() string {
 	return pt.Hostname.ForDisplay() + "/" + pt.Namespace + "/" + pt.Type
 }
 
+// ForDisplay returns a user-friendly FQN string, simplified for readability. If
+// the provider is using the default hostname, the hostname is omitted.
+func (pt Provider) ForDisplay() string {
+	if pt.IsZero() {
+		panic("called ForDisplay on zero-value addrs.Provider")
+	}
+
+	if pt.Hostname == DefaultRegistryHost {
+		return pt.Namespace + "/" + pt.Type
+	}
+	return pt.Hostname.ForDisplay() + "/" + pt.Namespace + "/" + pt.Type
+}
+
 // NewProvider constructs a provider address from its parts, and normalizes
 // the namespace and type parts to lowercase using unicode case folding rules
 // so that resulting addrs.Provider values can be compared using standard

addrs/provider_test.go

@@ -7,6 +7,84 @@ import (
 	svchost "github.com/hashicorp/terraform-svchost"
 )
 
+func TestProviderString(t *testing.T) {
+	tests := []struct {
+		Input Provider
+		Want  string
+	}{
+		{
+			Provider{
+				Type:      "test",
+				Hostname:  DefaultRegistryHost,
+				Namespace: "hashicorp",
+			},
+			DefaultRegistryHost.ForDisplay() + "/hashicorp/test",
+		},
+		{
+			Provider{
+				Type:      "test",
+				Hostname:  "registry.terraform.com",
+				Namespace: "hashicorp",
+			},
+			"registry.terraform.com/hashicorp/test",
+		},
+		{
+			Provider{
+				Type:      "test",
+				Hostname:  DefaultRegistryHost,
+				Namespace: "othercorp",
+			},
+			DefaultRegistryHost.ForDisplay() + "/othercorp/test",
+		},
+	}
+
+	for _, test := range tests {
+		got := test.Input.String()
+		if got != test.Want {
+			t.Errorf("wrong result for %s\n", test.Input.String())
+		}
+	}
+}
+
+func TestProviderDisplay(t *testing.T) {
+	tests := []struct {
+		Input Provider
+		Want  string
+	}{
+		{
+			Provider{
+				Type:      "test",
+				Hostname:  DefaultRegistryHost,
+				Namespace: "hashicorp",
+			},
+			"hashicorp/test",
+		},
+		{
+			Provider{
+				Type:      "test",
+				Hostname:  "registry.terraform.com",
+				Namespace: "hashicorp",
+			},
+			"registry.terraform.com/hashicorp/test",
+		},
+		{
+			Provider{
+				Type:      "test",
+				Hostname:  DefaultRegistryHost,
+				Namespace: "othercorp",
+			},
+			"othercorp/test",
+		},
+	}
+
+	for _, test := range tests {
+		got := test.Input.ForDisplay()
+		if got != test.Want {
+			t.Errorf("wrong result for %s\n", test.Input.String())
+		}
+	}
+}
+
 func TestProviderIsDefault(t *testing.T) {
 	tests := []struct {
 		Input Provider

command/init.go

@@ -461,50 +461,50 @@ func (c *InitCommand) getProviders(earlyConfig *earlyconfig.Config, state *state
 			))
 		},
 		ProviderAlreadyInstalled: func(provider addrs.Provider, selectedVersion getproviders.Version) {
-			c.Ui.Info(fmt.Sprintf("- Using previously-installed %s v%s", provider, selectedVersion))
+			c.Ui.Info(fmt.Sprintf("- Using previously-installed %s v%s", provider.ForDisplay(), selectedVersion))
 		},
 		BuiltInProviderAvailable: func(provider addrs.Provider) {
-			c.Ui.Info(fmt.Sprintf("- %s is built in to Terraform", provider))
+			c.Ui.Info(fmt.Sprintf("- %s is built in to Terraform", provider.ForDisplay()))
 		},
 		BuiltInProviderFailure: func(provider addrs.Provider, err error) {
 			diags = diags.Append(tfdiags.Sourceless(
 				tfdiags.Error,
 				"Invalid dependency on built-in provider",
-				fmt.Sprintf("Cannot use %s: %s.", provider, err),
+				fmt.Sprintf("Cannot use %s: %s.", provider.ForDisplay(), err),
 			))
 		},
 		QueryPackagesBegin: func(provider addrs.Provider, versionConstraints getproviders.VersionConstraints) {
 			if len(versionConstraints) > 0 {
-				c.Ui.Info(fmt.Sprintf("- Finding %s versions matching %q...", provider, getproviders.VersionConstraintsString(versionConstraints)))
+				c.Ui.Info(fmt.Sprintf("- Finding %s versions matching %q...", provider.ForDisplay(), getproviders.VersionConstraintsString(versionConstraints)))
 			} else {
-				c.Ui.Info(fmt.Sprintf("- Finding latest version of %s...", provider))
+				c.Ui.Info(fmt.Sprintf("- Finding latest version of %s...", provider.ForDisplay()))
 			}
 		},
 		LinkFromCacheBegin: func(provider addrs.Provider, version getproviders.Version, cacheRoot string) {
-			c.Ui.Info(fmt.Sprintf("- Using %s v%s from the shared cache directory", provider, version))
+			c.Ui.Info(fmt.Sprintf("- Using %s v%s from the shared cache directory", provider.ForDisplay(), version))
 		},
 		FetchPackageBegin: func(provider addrs.Provider, version getproviders.Version, location getproviders.PackageLocation) {
-			c.Ui.Info(fmt.Sprintf("- Installing %s v%s...", provider, version))
+			c.Ui.Info(fmt.Sprintf("- Installing %s v%s...", provider.ForDisplay(), version))
 		},
 		QueryPackagesFailure: func(provider addrs.Provider, err error) {
 			diags = diags.Append(tfdiags.Sourceless(
 				tfdiags.Error,
 				"Failed to query available provider packages",
-				fmt.Sprintf("Could not retrieve the list of available versions for provider %s: %s.", provider, err),
+				fmt.Sprintf("Could not retrieve the list of available versions for provider %s: %s.", provider.ForDisplay(), err),
 			))
 		},
 		LinkFromCacheFailure: func(provider addrs.Provider, version getproviders.Version, err error) {
 			diags = diags.Append(tfdiags.Sourceless(
 				tfdiags.Error,
 				"Failed to install provider from shared cache",
-				fmt.Sprintf("Error while importing %s v%s from the shared cache directory: %s.", provider, version, err),
+				fmt.Sprintf("Error while importing %s v%s from the shared cache directory: %s.", provider.ForDisplay(), version, err),
 			))
 		},
 		FetchPackageFailure: func(provider addrs.Provider, version getproviders.Version, err error) {
 			diags = diags.Append(tfdiags.Sourceless(
 				tfdiags.Error,
 				"Failed to install provider",
-				fmt.Sprintf("Error while installing %s v%s: %s.", provider, version, err),
+				fmt.Sprintf("Error while installing %s v%s: %s.", provider.ForDisplay(), version, err),
 			))
 		},
 	}