Function renderPartialIndexWhere

packages/sql/src/AbstractSqlDriver.ts:2970–3027

* Renders a `FilterQuery` predicate into a SQL fragment (without the `WHERE` keyword and * without table-alias prefixes) suitable for inlining into a partial-index DDL statement. * Used by `DatabaseTable.addIndex` when the user passes an object `where` on `@Index` / * `@Unique`. Strings are

(entityName: EntityName<T>, where: string | FilterQuery<T>)

   * `@Unique`. Strings are returned unchanged.
   */
  renderPartialIndexWhere<T extends object>(entityName: EntityName<T>, where: string | FilterQuery<T>): string {
    if (typeof where === 'string') {
      return where;
    }

    const name = Utils.className(entityName);

    if (where == null || (Utils.isPlainObject(where) && Object.keys(where as Dictionary).length === 0)) {
      throw new Error(`Cannot render partial-index predicate for entity '${name}': \`where\` is empty.`);
    }

    const alias = '__p';
    const qb = this.createQueryBuilder(entityName, undefined, undefined, undefined, undefined, alias);
    qb.where(where as any);
    const sql = qb.getFormattedQuery();

    // Relation traversal produces join clauses whose aliased identifiers can't be inlined
    // into a CREATE INDEX ... WHERE clause — reject with a clear error rather than emitting broken DDL.
    if (/\bjoin\b/i.test(sql.split(/\bwhere\b/i)[0])) {
      throw new Error(
        `Cannot render partial-index predicate for entity '${name}': \`where\` may not traverse relations.`,
      );
    }

    // Anchor at end-of-string only — the synthetic QB has no top-level order by / limit /
    // group by / having / offset, so any such keyword inside the captured predicate is
    // inside a subquery and must not terminate the match.
    const match = /\bwhere\s+([\s\S]+)$/i.exec(sql);

    if (!match) {
      throw new Error(`Failed to render partial-index predicate for entity '${name}': ${sql}`);
    }

    const quote = (s: string) => this.platform.quoteIdentifier(s);
    const aliasPrefix = new RegExp(`${quote(alias).replace(/[[\]]/g, '\\$&')}\\.`, 'g');
    const stripped = match[1].replace(aliasPrefix, '').trim();

    // Any qualified column reference remaining after the alias strip points at another table or
    // subquery and can't be inlined into a CREATE INDEX ... WHERE predicate. Covers both
    // QB-generated sub-aliases (quoted, e.g. `"e0"."col"`) and raw fragments with bare refs
    // (e.g. `raw('other_table.col = 1')`). String literals are erased first so dots inside
    // them (e.g. JSON path operands like `'$.path'`) don't trip the guard.
    // Both patterns use a `(?!\s*\()` lookahead so schema-qualified function calls
    // (`pg_catalog.lower(name)`, `"public".my_func(col)`) are accepted — only `<id>.<id>` not
    // followed by `(` is treated as a cross-table column reference.
    const withoutStrings = stripped.replace(/'(?:[^']|'')*'/g, "''");
    const quotedIdent = String.raw`(?:"(?:[^"]|"")+"|\`(?:[^\`]|\`\`)+\`|\[(?:[^\]]|\]\])+\])`;
    const anyIdent = `(?:${quotedIdent}|[A-Za-z_]\\w*)`;
    const quotedCrossRef = new RegExp(`${quotedIdent}\\s*\\.\\s*${anyIdent}(?!\\s*\\()`);
    const bareCrossRef = /\b[A-Za-z_]\w*\s*\.\s*[A-Za-z_]\w*\b(?!\s*\()/;
    if (quotedCrossRef.test(withoutStrings) || bareCrossRef.test(withoutStrings)) {
      throw new Error(
        `Cannot render partial-index predicate for entity '${name}': \`where\` references another table or subquery which cannot be inlined into a CREATE INDEX ... WHERE clause.`,
      );
    }

    return stripped;
  }