fix: preserve INCLUDE columns on CREATE INDEX (#385) (#390)

The index inspector was using indnatts (total columns) for both key and
include columns, causing INCLUDE columns to be merged into regular indexed
columns. Now uses indnkeyatts to extract only key columns, and separately
extracts include columns from positions indnkeyatts+1 through indnatts.

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: tianzhou

internal/diff/index.go

@@ -121,6 +121,18 @@ func generateIndexSQLWithName(index *ir.Index, indexName string, targetSchema st
 	}
 	builder.WriteString(")")
 
+	// INCLUDE columns (non-key columns stored in the index)
+	if len(index.IncludeColumns) > 0 {
+		builder.WriteString(" INCLUDE (")
+		for i, col := range index.IncludeColumns {
+			if i > 0 {
+				builder.WriteString(", ")
+			}
+			builder.WriteString(col)
+		}
+		builder.WriteString(")")
+	}
+
 	// NULLS NOT DISTINCT for unique indexes (PostgreSQL 15+)
 	if index.NullsNotDistinct && index.Type == ir.IndexTypeUnique {
 		builder.WriteString(" NULLS NOT DISTINCT")

internal/diff/table.go

@@ -1511,6 +1511,16 @@ func indexesStructurallyEqual(oldIndex, newIndex *ir.Index) bool {
 		}
 	}
 
+	// Compare INCLUDE columns
+	if len(oldIndex.IncludeColumns) != len(newIndex.IncludeColumns) {
+		return false
+	}
+	for i, oldCol := range oldIndex.IncludeColumns {
+		if oldCol != newIndex.IncludeColumns[i] {
+			return false
+		}
+	}
+
 	return true
 }
 

ir/inspector.go

@@ -746,16 +746,17 @@ func (i *Inspector) buildIndexes(ctx context.Context, schema *IR, targetSchema s
 		}
 
 		index := &Index{
-			Schema:       schemaName,
-			Table:        tableName,
-			Name:         indexName,
-			Type:         indexType,
-			Method:       method,
-			IsPartial:    isPartial,
-			IsExpression: hasExpressions,
-			Where:        "",
-			Comment:      comment,
-			Columns:      []*IndexColumn{},
+			Schema:         schemaName,
+			Table:          tableName,
+			Name:           indexName,
+			Type:           indexType,
+			Method:         method,
+			IncludeColumns: indexRow.IncludeColumns,
+			IsPartial:      isPartial,
+			IsExpression:   hasExpressions,
+			Where:          "",
+			Comment:        comment,
+			Columns:        []*IndexColumn{},
 		}
 
 		// Check for NULLS NOT DISTINCT (PostgreSQL 15+)

ir/ir.go

@@ -251,11 +251,12 @@ type Index struct {
 	Type         IndexType      `json:"type"`
 	Method       string         `json:"method"` // btree, hash, gin, gist, etc.
 	Columns      []*IndexColumn `json:"columns"`
-	IsPartial        bool   `json:"is_partial"`                   // has a WHERE clause
-	IsExpression     bool   `json:"is_expression"`                // functional/expression index
-	Where            string `json:"where,omitempty"`              // partial index condition
-	NullsNotDistinct bool   `json:"nulls_not_distinct,omitempty"` // NULLS NOT DISTINCT (PG15+)
-	Comment          string `json:"comment,omitempty"`
+	IncludeColumns   []string `json:"include_columns,omitempty"`     // INCLUDE columns (non-key)
+	IsPartial        bool     `json:"is_partial"`                   // has a WHERE clause
+	IsExpression     bool     `json:"is_expression"`                // functional/expression index
+	Where            string   `json:"where,omitempty"`              // partial index condition
+	NullsNotDistinct bool     `json:"nulls_not_distinct,omitempty"` // NULLS NOT DISTINCT (PG15+)
+	Comment          string   `json:"comment,omitempty"`
 }
 
 // IndexColumn represents a column within an index

ir/queries/queries.sql

@@ -436,27 +436,32 @@ WITH index_base AS (
             ELSE false
         END as has_expressions,
         COALESCE(d.description, '') AS index_comment,
+        idx.indnkeyatts as num_key_columns,
         idx.indnatts as num_columns,
         ARRAY(
             SELECT pg_get_indexdef(idx.indexrelid, k::int, true)
-            FROM generate_series(1, idx.indnatts) k
+            FROM generate_series(1, idx.indnkeyatts) k
         ) as column_definitions,
         ARRAY(
             SELECT
                 CASE
                     WHEN (idx.indoption[k-1] & 1) = 1 THEN 'DESC'
                     ELSE 'ASC'
                 END
-            FROM generate_series(1, idx.indnatts) k
+            FROM generate_series(1, idx.indnkeyatts) k
         ) as column_directions,
         ARRAY(
             SELECT CASE
                 WHEN opc.opcdefault THEN ''  -- Omit default operator classes
                 ELSE COALESCE(opc.opcname, '')
             END
-            FROM generate_series(1, idx.indnatts) k
+            FROM generate_series(1, idx.indnkeyatts) k
             LEFT JOIN pg_opclass opc ON opc.oid = idx.indclass[k-1]
-        ) as column_opclasses
+        ) as column_opclasses,
+        ARRAY(
+            SELECT pg_get_indexdef(idx.indexrelid, k::int, true)
+            FROM generate_series(idx.indnkeyatts + 1, idx.indnatts) k
+        ) as include_columns
     FROM pg_index idx
     JOIN pg_class i ON i.oid = idx.indexrelid
     JOIN pg_class t ON t.oid = idx.indrelid
@@ -488,10 +493,12 @@ SELECT
     sp.partial_predicate,
     ib.has_expressions,
     ib.index_comment,
+    ib.num_key_columns,
     ib.num_columns,
     ib.column_definitions,
     ib.column_directions,
-    ib.column_opclasses
+    ib.column_opclasses,
+    ib.include_columns
 FROM index_base ib
 CROSS JOIN LATERAL (
     SELECT

ir/queries/queries.sql.go

@@ -7,6 +7,8 @@ CREATE TABLE IF NOT EXISTS users (
 
 CREATE INDEX IF NOT EXISTS idx_users_email ON users (email varchar_pattern_ops);
 
+CREATE INDEX IF NOT EXISTS idx_users_email_include ON users (email) INCLUDE (name);
+
 CREATE UNIQUE INDEX IF NOT EXISTS idx_users_email_unique ON users (email) NULLS NOT DISTINCT;
 
 CREATE INDEX IF NOT EXISTS idx_users_id ON users (id);

testdata/diff/create_index/add_index/diff.sql

@@ -12,3 +12,5 @@ CREATE INDEX idx_users_id ON public.users (id);
 CREATE INDEX "public.idx_users" ON public.users (email, name);
 -- Test NULLS NOT DISTINCT (issue #355)
 CREATE UNIQUE INDEX idx_users_email_unique ON public.users (email) NULLS NOT DISTINCT;
+-- Test INCLUDE columns (issue #385)
+CREATE INDEX idx_users_email_include ON public.users (email) INCLUDE (name);

testdata/diff/create_index/add_index/new.sql

@@ -20,6 +20,12 @@
           "operation": "create",
           "path": "public.users.idx_users_email"
         },
+        {
+          "sql": "CREATE INDEX IF NOT EXISTS idx_users_email_include ON users (email) INCLUDE (name);",
+          "type": "table.index",
+          "operation": "create",
+          "path": "public.users.idx_users_email_include"
+        },
         {
           "sql": "CREATE UNIQUE INDEX IF NOT EXISTS idx_users_email_unique ON users (email) NULLS NOT DISTINCT;",
           "type": "table.index",

testdata/diff/create_index/add_index/plan.json

@@ -7,6 +7,8 @@ CREATE TABLE IF NOT EXISTS users (
 
 CREATE INDEX IF NOT EXISTS idx_users_email ON users (email varchar_pattern_ops);
 
+CREATE INDEX IF NOT EXISTS idx_users_email_include ON users (email) INCLUDE (name);
+
 CREATE UNIQUE INDEX IF NOT EXISTS idx_users_email_unique ON users (email) NULLS NOT DISTINCT;
 
 CREATE INDEX IF NOT EXISTS idx_users_id ON users (id);