Add sequence support (#35)

Add sequence support

README.md

@@ -27,6 +27,7 @@ pg-schema-diff plan --dsn "postgres://postgres:postgres@localhost:5432/postgres"
 - Indexes
 - Partitions
 - Functions/Triggers  (functions created by extensions are ignored)
+- Sequences
 
 *A comprehensive set of features to ensure the safety of planned migrations:*
 - Dangerous operations are flagged as hazards and must be approved before a migration can be applied.
@@ -130,7 +131,6 @@ Note, the library only currently supports diffing the *public* schema. Support f
 *Unsupported*:
 - (On roadmap) Foreign key constraints
 - (On roadmap) Diffing schemas other than "public"
-- (On roadmap) Serials and sequences
 - (On roadmap) Unique constraints (unique indexes are supported but not unique constraints)
 - (On roadmap) Adding and remove partitions from an existing partitioned table
 - (On roadmap) Check constraints localized to specific partitions

internal/migration_acceptance_tests/acceptance_test.go

@@ -29,6 +29,8 @@ type (
 		//
 		// If no outputState is specified, the newSchemaDDL will be used
 		outputState []string
+		// empty asserts the plan is empty
+		empty bool
 	}
 
 	acceptanceTestCase struct {
@@ -128,6 +130,10 @@ func (suite *acceptanceTestSuite) runSubtest(tc acceptanceTestCase, expects expe
 	}
 	suite.Require().NoError(err)
 
+	if expects.empty {
+		// It shouldn't be necessary, but we'll run all checks below this point just in case rather than exiting early
+		suite.Empty(plan.Statements)
+	}
 	suite.ElementsMatch(tc.expectedHazardTypes, getUniqueHazardTypesFromStatements(plan.Statements), prettySprintPlan(plan))
 
 	// Apply the plan

internal/migration_acceptance_tests/check_constraint_cases_test.go

@@ -25,6 +25,12 @@ var checkConstraintCases = []acceptanceTestCase{
 			);
 			`,
 		},
+		vanillaExpectations: expectations{
+			empty: true,
+		},
+		dataPackingExpectations: expectations{
+			empty: true,
+		},
 	},
 	{
 		name: "Add check constraint",

internal/migration_acceptance_tests/column_cases_test.go

@@ -27,6 +27,12 @@ var columnAcceptanceTestCases = []acceptanceTestCase{
 			);
 			`,
 		},
+		vanillaExpectations: expectations{
+			empty: true,
+		},
+		dataPackingExpectations: expectations{
+			empty: true,
+		},
 	},
 	{
 		name: "Add one column with default",
@@ -82,6 +88,24 @@ var columnAcceptanceTestCases = []acceptanceTestCase{
 			`,
 		},
 	},
+	{
+		name: "Add one column with serial",
+		oldSchemaDDL: []string{
+			`
+			CREATE TABLE foobar(
+			    id INT PRIMARY KEY
+			);
+			`,
+		},
+		newSchemaDDL: []string{
+			`
+			CREATE TABLE foobar(
+			    id INT PRIMARY KEY,
+				my_new_column SERIAL NOT NULL
+			);
+			`,
+		},
+	},
 	{
 		name: "Add one column with all options",
 		oldSchemaDDL: []string{
@@ -177,26 +201,65 @@ var columnAcceptanceTestCases = []acceptanceTestCase{
 		},
 	},
 	{
-		name: "Modify data type (varchar -> char)",
+		name: "Delete one column with serial",
+		oldSchemaDDL: []string{
+			`
+			CREATE TABLE "Foobar"(
+			    id BIGSERIAL PRIMARY KEY
+			);
+			`,
+		},
+		newSchemaDDL: []string{
+			`
+			CREATE TABLE "Foobar"(
+			);
+			`,
+		},
+		expectedHazardTypes: []diff.MigrationHazardType{
+			diff.MigrationHazardTypeAcquiresAccessExclusiveLock,
+			diff.MigrationHazardTypeDeletesData,
+			diff.MigrationHazardTypeIndexDropped,
+		},
+	},
+	{
+		name: "Modify data type (int -> serial)",
 		oldSchemaDDL: []string{
 			`
 			CREATE TABLE foobar(
 			    id INT PRIMARY KEY,
-				foobar VARCHAR(255) NOT NULL
+				foobar INT NOT NULL
 			);
 			`,
 		},
 		newSchemaDDL: []string{
 			`
 			CREATE TABLE foobar(
 			    id INT PRIMARY KEY,
-				foobar CHAR NOT NULL
+				foobar SERIAL NOT NULL
+			);
+			`,
+		},
+	},
+	{
+		name: "Modify data type (serial -> int)",
+		oldSchemaDDL: []string{
+			`
+			CREATE TABLE foobar(
+			    id INT PRIMARY KEY,
+				foobar SERIAL NOT NULL
+			);
+			`,
+		},
+		newSchemaDDL: []string{
+			`
+			CREATE TABLE foobar(
+			    id INT PRIMARY KEY,
+				foobar INT NOT NULL
 			);
 			`,
 		},
 		expectedHazardTypes: []diff.MigrationHazardType{
-			diff.MigrationHazardTypeAcquiresAccessExclusiveLock,
-			diff.MigrationHazardTypeImpactsDatabasePerformance,
+			diff.MigrationHazardTypeDeletesData,
 		},
 	},
 	{

internal/migration_acceptance_tests/function_cases_test.go

@@ -37,6 +37,12 @@ var functionAcceptanceTestCases = []acceptanceTestCase{
 			$$ LANGUAGE plpgsql;
 			`,
 		},
+		vanillaExpectations: expectations{
+			empty: true,
+		},
+		dataPackingExpectations: expectations{
+			empty: true,
+		},
 	},
 	{
 		name:         "Create functions (with conflicting names)",

internal/migration_acceptance_tests/index_cases_test.go

@@ -31,6 +31,12 @@ var indexAcceptanceTestCases = []acceptanceTestCase{
 			CREATE UNIQUE INDEX some_other_idx ON foobar (bar DESC, fizz);
 			`,
 		},
+		vanillaExpectations: expectations{
+			empty: true,
+		},
+		dataPackingExpectations: expectations{
+			empty: true,
+		},
 	},
 	{
 		name: "Add a normal index",

internal/migration_acceptance_tests/local_partition_index_cases_test.go

@@ -41,6 +41,12 @@ var localPartitionIndexAcceptanceTestCases = []acceptanceTestCase{
 			CREATE UNIQUE INDEX foobar_2_some_unique_idx ON foobar_2 (foo);
 			`,
 		},
+		vanillaExpectations: expectations{
+			empty: true,
+		},
+		dataPackingExpectations: expectations{
+			empty: true,
+		},
 	},
 	{
 		name: "Add local indexes",

internal/migration_acceptance_tests/partitioned_index_cases_test.go

@@ -39,6 +39,12 @@ var partitionedIndexAcceptanceTestCases = []acceptanceTestCase{
 			CREATE UNIQUE INDEX some_other_idx ON foobar(foo DESC, fizz);
 			`,
 		},
+		vanillaExpectations: expectations{
+			empty: true,
+		},
+		dataPackingExpectations: expectations{
+			empty: true,
+		},
 	},
 	{
 		name: "Add a normal partitioned index",