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Fix implicit result column name/alias for SELECT item literals with NULL bytes #314

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JanJakes merged 1 commit into from
Jan 30, 2026
+15 −0
Merged

Fix implicit result column name/alias for SELECT item literals with NULL bytes #314

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8 changes: 8 additions & 0 deletions tests/WP_SQLite_Driver_Tests.php
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Original file line number Diff line number Diff line change
Expand Up @@ -6138,6 +6138,14 @@ public function testSelectColumnNames(): void {
$this->assertQuery( 'CREATE TABLE t (id INT, name VARCHAR(255))' );
$this->assertQuery( 'INSERT INTO t (id, name) VALUES (1, "John"), (2, "Jane")' );

// Literal with a NULL byte (no explicit alias).
$result = $this->assertQuery( "SELECT 'abc\0def'" );
$this->assertSame( array( 'abc' ), array_keys( (array) $result[0] ) );

// Literal with a NULL byte (with an explicit alias).
$result = $this->assertQuery( "SELECT 'abc\0def' AS `col1`" );
$this->assertSame( array( 'col1' ), array_keys( (array) $result[0] ) );

// Columns (no explicit alias).
$result = $this->assertQuery( 'SELECT id, name FROM t' );
$this->assertSame( array( 'id', 'name' ), array_keys( (array) $result[0] ) );
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7 changes: 7 additions & 0 deletions wp-includes/sqlite-ast/class-wp-pdo-mysql-on-sqlite.php
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Expand Up @@ -4566,6 +4566,13 @@ public function translate_select_item( WP_Parser_Node $node ): string {
$is_text_string_literal = $text_string_literal && $item === $this->translate( $text_string_literal );
if ( $is_text_string_literal ) {
$alias = $text_string_literal->get_first_child_token()->get_value();

// When the literal value contains a NULL byte, MySQL truncates the
// resulting identifier at the position of the first one of them.
$fist_null_byte_pos = strpos( $alias, "\0" );
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@adamziel adamziel Jan 30, 2026

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Does this matter in more places than just translate_select_item?

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@JanJakes JanJakes Jan 30, 2026 •
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@adamziel I will check that a bit deeper in a follow-up PR. There is the case where you type this explicitly (SELECT 1 AS 'a\0b'), and we need a follow-up to tackle that. Then, I think there is no other way where a string literal gets "converted" to an alias, but—I found some inconsistencies in how we process string literals vs. quoted identifiers and want to improve that too. We seem to treat them the same, but they shouldn't. It might be an interesting edge case bug going down to the lexer.

if ( false !== $fist_null_byte_pos ) {
$alias = substr( $alias, 0, $fist_null_byte_pos );
}
return sprintf( '%s AS %s', $item, $this->quote_sqlite_identifier( $alias ) );
}

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