command: Fix TestInit_getProvider

After all of the refactoring we were no longer checking the Terraform
version field in a state file, causing this test to fail.

This restores that check, though with a slightly different error message.

command/init_test.go

@@ -691,7 +691,7 @@ func TestInit_getProvider(t *testing.T) {
 		}
 
 		errMsg := ui.ErrorWriter.String()
-		if !strings.Contains(errMsg, "future Terraform version") {
+		if !strings.Contains(errMsg, "which is newer than current") {
 			t.Fatal("unexpected error:", errMsg)
 		}
 	})

states/statefile/read.go

@@ -62,6 +62,15 @@ func Read(r io.Reader) (*File, error) {
 		panic("readState returned nil state with no errors")
 	}
 
+	if state.TerraformVersion != nil && state.TerraformVersion.GreaterThan(tfversion.SemVer) {
+		return state, fmt.Errorf(
+			"state snapshot was created by Terraform v%s, which is newer than current v%s; upgrade to Terraform v%s or greater to work with this state",
+			state.TerraformVersion,
+			tfversion.SemVer,
+			state.TerraformVersion,
+		)
+	}
+
 	return state, diags.Err()
 }