Don't use d.GetOk() when the zero value is a required attribute.

Add "pathological" test.

builtin/providers/postgresql/resource_postgresql_database.go

@@ -181,32 +181,44 @@ func resourcePostgreSQLDatabaseCreate(d *schema.ResourceData, meta interface{})
 			val = "pg_default"
 			d.Set(dbTablespaceAttr, val)
 		case opt.hclKey == dbTemplateAttr:
-			if val == "" {
+			switch {
+			case val == "":
 				val = "template0"
 				d.Set(dbTemplateAttr, val)
-			} else if strings.ToUpper(val) == "DEFAULT" {
+			case strings.ToUpper(val) == "DEFAULT":
 				val = ""
+			default:
+				d.Set(dbTemplateAttr, val)
 			}
 		case opt.hclKey == dbEncodingAttr:
-			if val == "" {
+			switch {
+			case val == "":
 				val = "UTF8"
 				d.Set(dbEncodingAttr, val)
-			} else if strings.ToUpper(val) == "DEFAULT" {
+			case strings.ToUpper(val) == "DEFAULT":
 				val = ""
+			default:
+				d.Set(dbEncodingAttr, val)
 			}
 		case opt.hclKey == dbCollationAttr:
-			if val == "" {
+			switch {
+			case val == "":
 				val = "C"
 				d.Set(dbCollationAttr, val)
-			} else if strings.ToUpper(val) == "DEFAULT" {
+			case strings.ToUpper(val) == "DEFAULT":
 				val = ""
+			default:
+				d.Set(dbCollationAttr, val)
 			}
 		case opt.hclKey == dbCTypeAttr:
-			if val == "" {
+			switch {
+			case val == "":
 				val = "C"
 				d.Set(dbCTypeAttr, val)
-			} else if strings.ToUpper(val) == "DEFAULT" {
+			case strings.ToUpper(val) == "DEFAULT":
 				val = ""
+			default:
+				d.Set(dbCTypeAttr, val)
 			}
 		}
 
@@ -216,12 +228,7 @@ func resourcePostgreSQLDatabaseCreate(d *schema.ResourceData, meta interface{})
 	}
 
 	for _, opt := range intOpts {
-		v, ok := d.GetOk(opt.hclKey)
-		if !ok {
-			continue
-		}
-
-		val := v.(int)
+		val := d.Get(opt.hclKey).(int)
 		createOpts = append(createOpts, fmt.Sprintf("%s=%d", opt.sqlKey, val))
 	}
 

builtin/providers/postgresql/resource_postgresql_database_test.go

@@ -26,25 +26,67 @@ func TestAccPostgresqlDatabase_Basic(t *testing.T) {
 					resource.TestCheckResourceAttr(
 						"postgresql_database.mydb", "owner", "myrole"),
 					resource.TestCheckResourceAttr(
-						"postgresql_database.all_opts", "owner", "myrole"),
+						"postgresql_database.default_opts", "owner", "myrole"),
 					resource.TestCheckResourceAttr(
-						"postgresql_database.all_opts", "name", "all_opts_name"),
+						"postgresql_database.default_opts", "name", "default_opts_name"),
 					resource.TestCheckResourceAttr(
-						"postgresql_database.all_opts", "template", "template0"),
+						"postgresql_database.default_opts", "template", "template0"),
 					resource.TestCheckResourceAttr(
-						"postgresql_database.all_opts", "encoding", "UTF8"),
+						"postgresql_database.default_opts", "encoding", "UTF8"),
 					resource.TestCheckResourceAttr(
-						"postgresql_database.all_opts", "lc_collate", "C"),
+						"postgresql_database.default_opts", "lc_collate", "C"),
 					resource.TestCheckResourceAttr(
-						"postgresql_database.all_opts", "lc_ctype", "C"),
+						"postgresql_database.default_opts", "lc_ctype", "C"),
 					resource.TestCheckResourceAttr(
-						"postgresql_database.all_opts", "tablespace_name", "pg_default"),
+						"postgresql_database.default_opts", "tablespace_name", "pg_default"),
 					resource.TestCheckResourceAttr(
-						"postgresql_database.all_opts", "connection_limit", "-1"),
+						"postgresql_database.default_opts", "connection_limit", "-1"),
 					resource.TestCheckResourceAttr(
-						"postgresql_database.all_opts", "allow_connections", "false"),
+						"postgresql_database.default_opts", "allow_connections", "true"),
 					resource.TestCheckResourceAttr(
-						"postgresql_database.all_opts", "is_template", "false"),
+						"postgresql_database.default_opts", "is_template", "false"),
+
+					resource.TestCheckResourceAttr(
+						"postgresql_database.modified_opts", "owner", "myrole"),
+					resource.TestCheckResourceAttr(
+						"postgresql_database.modified_opts", "name", "custom_template_db"),
+					resource.TestCheckResourceAttr(
+						"postgresql_database.modified_opts", "template", "template0"),
+					resource.TestCheckResourceAttr(
+						"postgresql_database.modified_opts", "encoding", "UTF8"),
+					resource.TestCheckResourceAttr(
+						"postgresql_database.modified_opts", "lc_collate", "en_US.UTF-8"),
+					resource.TestCheckResourceAttr(
+						"postgresql_database.modified_opts", "lc_ctype", "en_US.UTF-8"),
+					resource.TestCheckResourceAttr(
+						"postgresql_database.modified_opts", "tablespace_name", "pg_default"),
+					resource.TestCheckResourceAttr(
+						"postgresql_database.modified_opts", "connection_limit", "10"),
+					resource.TestCheckResourceAttr(
+						"postgresql_database.modified_opts", "allow_connections", "false"),
+					resource.TestCheckResourceAttr(
+						"postgresql_database.modified_opts", "is_template", "true"),
+
+					resource.TestCheckResourceAttr(
+						"postgresql_database.pathological_opts", "owner", "myrole"),
+					resource.TestCheckResourceAttr(
+						"postgresql_database.pathological_opts", "name", "bad_template_db"),
+					resource.TestCheckResourceAttr(
+						"postgresql_database.pathological_opts", "template", "template0"),
+					resource.TestCheckResourceAttr(
+						"postgresql_database.pathological_opts", "encoding", "LATIN1"),
+					resource.TestCheckResourceAttr(
+						"postgresql_database.pathological_opts", "lc_collate", "C"),
+					resource.TestCheckResourceAttr(
+						"postgresql_database.pathological_opts", "lc_ctype", "C"),
+					resource.TestCheckResourceAttr(
+						"postgresql_database.pathological_opts", "tablespace_name", "pg_default"),
+					resource.TestCheckResourceAttr(
+						"postgresql_database.pathological_opts", "connection_limit", "0"),
+					resource.TestCheckResourceAttr(
+						"postgresql_database.pathological_opts", "allow_connections", "true"),
+					resource.TestCheckResourceAttr(
+						"postgresql_database.pathological_opts", "is_template", "true"),
 				),
 			},
 		},
@@ -154,8 +196,8 @@ resource "postgresql_database" "mydb2" {
    owner = "${postgresql_role.myrole.name}"
 }
 
-resource "postgresql_database" "all_opts" {
-   name = "all_opts_name"
+resource "postgresql_database" "default_opts" {
+   name = "default_opts_name"
    owner = "${postgresql_role.myrole.name}"
    template = "template0"
    encoding = "UTF8"
@@ -163,10 +205,36 @@ resource "postgresql_database" "all_opts" {
    lc_ctype = "C"
    tablespace_name = "pg_default"
    connection_limit = -1
-   allow_connections = false
+   allow_connections = true
    is_template = false
 }
 
+resource "postgresql_database" "modified_opts" {
+   name = "custom_template_db"
+   owner = "${postgresql_role.myrole.name}"
+   template = "template0"
+   encoding = "UTF8"
+   lc_collate = "en_US.UTF-8"
+   lc_ctype = "en_US.UTF-8"
+   tablespace_name = "pg_default"
+   connection_limit = 10
+   allow_connections = false
+   is_template = true
+}
+
+resource "postgresql_database" "pathological_opts" {
+   name = "bad_template_db"
+   owner = "${postgresql_role.myrole.name}"
+   template = "template0"
+   encoding = "LATIN1"
+   lc_collate = "C"
+   lc_ctype = "C"
+   tablespace_name = "pg_default"
+   connection_limit = 0
+   allow_connections = true
+   is_template = true
+}
+
 resource "postgresql_database" "mydb_default_owner" {
    name = "mydb_default_owner"
 }