Expose source_tables on the plugin Query message

internal/cmd/shim.go

@@ -161,6 +161,7 @@ func pluginQueries(r *compiler.Result) []*plugin.Query {
 			Params:          params,
 			Filename:        q.Metadata.Filename,
 			InsertIntoTable: iit,
+			SourceTables:    q.SourceTables,
 		})
 	}
 	return out

internal/compiler/parse.go

@@ -181,6 +181,7 @@ func (c *Compiler) parseQuery(stmt ast.Node, src string, o opts.Parser) (*Query,
 		Columns:         anlys.Columns,
 		SQL:             trimmed,
 		InsertIntoTable: anlys.Table,
+		SourceTables:    sourceTableNames(raw.Stmt),
 	}, nil
 }
 

internal/compiler/query.go

@@ -48,6 +48,12 @@ type Query struct {
 	Columns  []*Column
 	Params   []Parameter
 
+	// SourceTables lists the names of the base tables the query reads from,
+	// including tables that appear only in joins, subqueries, or common table
+	// expression bodies. Common table expression names and the target relations
+	// of write statements are excluded.
+	SourceTables []string
+
 	// Needed for CopyFrom
 	InsertIntoTable *ast.TableName
 

internal/compiler/source_tables.go

@@ -0,0 +1,72 @@
+package compiler
+
+import (
+	"sort"
+
+	"github.com/sqlc-dev/sqlc/internal/sql/ast"
+	"github.com/sqlc-dev/sqlc/internal/sql/astutils"
+)
+
+// sourceTableNames returns the sorted, deduplicated names of the base tables a
+// statement reads from. It covers every table referenced in a FROM, a JOIN, or
+// a subquery in any clause, including the bodies of common table expressions.
+// The names of common table expressions and the target relations of INSERT,
+// UPDATE, DELETE, and TRUNCATE statements are not reads and are excluded.
+func sourceTableNames(root ast.Node) []string {
+	cteNames := map[string]struct{}{}
+	writeTargets := map[*ast.RangeVar]struct{}{}
+
+	collect := astutils.VisitorFunc(func(node ast.Node) {
+		switch n := node.(type) {
+		case *ast.CommonTableExpr:
+			if n.Ctename != nil {
+				cteNames[*n.Ctename] = struct{}{}
+			}
+		case *ast.InsertStmt:
+			if n.Relation != nil {
+				markRangeVars(writeTargets, n.Relation)
+			}
+		case *ast.UpdateStmt:
+			if n.Relations != nil {
+				markRangeVars(writeTargets, n.Relations)
+			}
+		case *ast.DeleteStmt:
+			if n.Relations != nil {
+				markRangeVars(writeTargets, n.Relations)
+			}
+		case *ast.TruncateStmt:
+			if n.Relations != nil {
+				markRangeVars(writeTargets, n.Relations)
+			}
+		}
+	})
+	astutils.Walk(collect, root)
+
+	seen := map[string]struct{}{}
+	var names []string
+	for _, rv := range rangeVars(root) {
+		if _, ok := writeTargets[rv]; ok {
+			continue
+		}
+		table, err := ParseTableName(rv)
+		if err != nil {
+			continue
+		}
+		if _, ok := cteNames[table.Name]; ok {
+			continue
+		}
+		if _, ok := seen[table.Name]; ok {
+			continue
+		}
+		seen[table.Name] = struct{}{}
+		names = append(names, table.Name)
+	}
+	sort.Strings(names)
+	return names
+}
+
+func markRangeVars(set map[*ast.RangeVar]struct{}, node ast.Node) {
+	for _, rv := range rangeVars(node) {
+		set[rv] = struct{}{}
+	}
+}

internal/compiler/source_tables_test.go

@@ -0,0 +1,60 @@
+package compiler
+
+import (
+	"reflect"
+	"strings"
+	"testing"
+
+	"github.com/sqlc-dev/sqlc/internal/engine/postgresql"
+)
+
+func TestSourceTableNames(t *testing.T) {
+	for _, tc := range []struct {
+		name string
+		sql  string
+		want []string
+	}{
+		{
+			name: "cte, join and subquery dependencies",
+			sql: `WITH filtered_accounts AS (
+				SELECT account_id FROM accounts WHERE accounts.space_id = $1
+				AND NOT EXISTS (
+					SELECT 1 FROM account_tags t WHERE t.account_id = accounts.account_id
+				)
+			)
+			SELECT acc.* FROM accounts acc
+			JOIN filtered_accounts fa ON acc.account_id = fa.account_id
+			LEFT JOIN transactions t ON t.debit_account_id = acc.account_id`,
+			want: []string{"account_tags", "accounts", "transactions"},
+		},
+		{
+			name: "deduplicated across aliases",
+			sql:  `SELECT a1.account_id FROM accounts a1 JOIN accounts a2 ON a1.space_id = a2.space_id`,
+			want: []string{"accounts"},
+		},
+		{
+			name: "insert excludes write target, includes read",
+			sql:  `INSERT INTO audit_log (account_id) SELECT account_id FROM accounts`,
+			want: []string{"accounts"},
+		},
+		{
+			name: "no base tables",
+			sql:  `SELECT 1`,
+			want: nil,
+		},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			stmts, err := postgresql.NewParser().Parse(strings.NewReader(tc.sql + ";"))
+			if err != nil {
+				t.Fatalf("parse: %v", err)
+			}
+			if len(stmts) != 1 {
+				t.Fatalf("expected 1 statement, got %d", len(stmts))
+			}
+			got := sourceTableNames(stmts[0].Raw.Stmt)
+			if !reflect.DeepEqual(got, tc.want) {
+				t.Errorf("sourceTableNames\n  got:  %v\n  want: %v", got, tc.want)
+			}
+		})
+	}
+}

internal/endtoend/testdata/codegen_json/gen/codegen.json

@@ -65079,7 +65079,10 @@
       ],
       "comments": [],
       "filename": "query.sql",
-      "insert_into_table": null
+      "insert_into_table": null,
+      "source_tables": [
+        "authors"
+      ]
     },
     {
       "text": "SELECT id, name, bio FROM authors\nORDER BY name",
@@ -65168,7 +65171,10 @@
       "params": [],
       "comments": [],
       "filename": "query.sql",
-      "insert_into_table": null
+      "insert_into_table": null,
+      "source_tables": [
+        "authors"
+      ]
     },
     {
       "text": "INSERT INTO authors (\n          name, bio\n) VALUES (\n  $1, $2\n)\nRETURNING id, name, bio",
@@ -65320,7 +65326,8 @@
         "catalog": "",
         "schema": "",
         "name": "authors"
-      }
+      },
+      "source_tables": []
     },
     {
       "text": "DELETE FROM authors\nWHERE id = $1",
@@ -65360,7 +65367,8 @@
       ],
       "comments": [],
       "filename": "query.sql",
-      "insert_into_table": null
+      "insert_into_table": null,
+      "source_tables": []
     }
   ],
   "sqlc_version": "v1.31.1",

internal/endtoend/testdata/process_plugin_sqlc_gen_json/gen/codegen.json

@@ -65081,7 +65081,10 @@
       ],
       "comments": [],
       "filename": "query.sql",
-      "insert_into_table": null
+      "insert_into_table": null,
+      "source_tables": [
+        "authors"
+      ]
     },
     {
       "text": "SELECT id, name, bio FROM authors\nORDER BY name",
@@ -65170,7 +65173,10 @@
       "params": [],
       "comments": [],
       "filename": "query.sql",
-      "insert_into_table": null
+      "insert_into_table": null,
+      "source_tables": [
+        "authors"
+      ]
     },
     {
       "text": "INSERT INTO authors (\n          name, bio\n) VALUES (\n  $1, $2\n)\nRETURNING id, name, bio",
@@ -65322,7 +65328,8 @@
         "catalog": "",
         "schema": "",
         "name": "authors"
-      }
+      },
+      "source_tables": []
     },
     {
       "text": "DELETE FROM authors\nWHERE id = $1",
@@ -65362,7 +65369,8 @@
       ],
       "comments": [],
       "filename": "query.sql",
-      "insert_into_table": null
+      "insert_into_table": null,
+      "source_tables": []
     }
   ],
   "sqlc_version": "v1.31.1",

protos/plugin/codegen.proto

@@ -111,6 +111,7 @@ message Query {
   repeated string comments = 6 [json_name = "comments"];
   string filename = 7 [json_name = "filename"];
   Identifier insert_into_table = 8 [json_name = "insert_into_table"];
+  repeated string source_tables = 9 [json_name = "source_tables"];
 }
 
 message Parameter {