fix: multiple statements from the same column

internal/plan/rewrite.go

@@ -78,9 +78,16 @@ func generateRewrite(d diff.Diff, newlyCreatedTables map[string]bool, newlyCreat
 	case diff.DiffTypeTableColumn:
 		if d.Operation == diff.DiffOperationAlter {
 			if columnDiff, ok := d.Source.(*diff.ColumnDiff); ok {
-				// Check if this is a NOT NULL addition
+				// Check if this is a NOT NULL addition AND this specific statement is for SET NOT NULL
+				// Multiple statements can be generated from the same ColumnDiff (e.g., SET NOT NULL + SET DEFAULT),
+				// so we must only rewrite the statement that actually contains SET NOT NULL
 				if columnDiff.Old.IsNullable && !columnDiff.New.IsNullable {
-					return generateColumnNotNullRewrite(columnDiff, d.Path)
+					// Verify this diff's SQL actually contains SET NOT NULL
+					for _, stmt := range d.Statements {
+						if strings.Contains(stmt.SQL, "SET NOT NULL") {
+							return generateColumnNotNullRewrite(columnDiff, d.Path)
+						}
+					}
 				}
 			}
 		}

testdata/diff/create_table/add_default_not_null/diff.sql

@@ -0,0 +1,2 @@
+ALTER TABLE people ALTER COLUMN created_at SET NOT NULL;
+ALTER TABLE people ALTER COLUMN created_at SET DEFAULT now();

testdata/diff/create_table/add_default_not_null/new.sql

@@ -0,0 +1,4 @@
+CREATE TABLE public.people (
+    id bigint PRIMARY KEY GENERATED ALWAYS AS IDENTITY,
+    created_at timestamp with time zone DEFAULT NOW() NOT NULL
+);

testdata/diff/create_table/add_default_not_null/old.sql

@@ -0,0 +1,4 @@
+CREATE TABLE public.people (
+    id bigint PRIMARY KEY GENERATED ALWAYS AS IDENTITY,
+    created_at timestamp with time zone
+);

testdata/diff/create_table/add_default_not_null/plan.json

@@ -0,0 +1,44 @@
+{
+  "version": "1.0.0",
+  "pgschema_version": "1.6.2",
+  "created_at": "1970-01-01T00:00:00Z",
+  "source_fingerprint": {
+    "hash": "a5614a0f5b8d53ba131811b4a89cd3eddb434b6bd0398b7ec180199c8fba880d"
+  },
+  "groups": [
+    {
+      "steps": [
+        {
+          "sql": "ALTER TABLE people ADD CONSTRAINT created_at_not_null CHECK (created_at IS NOT NULL) NOT VALID;",
+          "type": "table.column",
+          "operation": "alter",
+          "path": "public.people.created_at"
+        },
+        {
+          "sql": "ALTER TABLE people VALIDATE CONSTRAINT created_at_not_null;",
+          "type": "table.column",
+          "operation": "alter",
+          "path": "public.people.created_at"
+        },
+        {
+          "sql": "ALTER TABLE people ALTER COLUMN created_at SET NOT NULL;",
+          "type": "table.column",
+          "operation": "alter",
+          "path": "public.people.created_at"
+        },
+        {
+          "sql": "ALTER TABLE people DROP CONSTRAINT created_at_not_null;",
+          "type": "table.column",
+          "operation": "alter",
+          "path": "public.people.created_at"
+        },
+        {
+          "sql": "ALTER TABLE people ALTER COLUMN created_at SET DEFAULT now();",
+          "type": "table.column",
+          "operation": "alter",
+          "path": "public.people.created_at"
+        }
+      ]
+    }
+  ]
+}

testdata/diff/create_table/add_default_not_null/plan.sql

@@ -0,0 +1,9 @@
+ALTER TABLE people ADD CONSTRAINT created_at_not_null CHECK (created_at IS NOT NULL) NOT VALID;
+
+ALTER TABLE people VALIDATE CONSTRAINT created_at_not_null;
+
+ALTER TABLE people ALTER COLUMN created_at SET NOT NULL;
+
+ALTER TABLE people DROP CONSTRAINT created_at_not_null;
+
+ALTER TABLE people ALTER COLUMN created_at SET DEFAULT now();

testdata/diff/create_table/add_default_not_null/plan.txt

@@ -0,0 +1,21 @@
+Plan: 1 to modify.
+
+Summary by type:
+  tables: 1 to modify
+
+Tables:
+  ~ people
+    ~ created_at (column)
+
+DDL to be executed:
+--------------------------------------------------
+
+ALTER TABLE people ADD CONSTRAINT created_at_not_null CHECK (created_at IS NOT NULL) NOT VALID;
+
+ALTER TABLE people VALIDATE CONSTRAINT created_at_not_null;
+
+ALTER TABLE people ALTER COLUMN created_at SET NOT NULL;
+
+ALTER TABLE people DROP CONSTRAINT created_at_not_null;
+
+ALTER TABLE people ALTER COLUMN created_at SET DEFAULT now();