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Translate empty bit-value literals to an empty blob literal #614

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Translate empty bit-value literals to an empty blob literal #614

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0f93b3d
Translate empty bit-value literals to an empty blob literal
x-rush Nov 5, 2026
d76edd1
Document the empty bit literal comparison semantics
x-rush Nov 6, 2026
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5 changes: 3 additions & 2 deletions packages/mysql-on-sqlite/src/sqlite/class-wp-mysql-on-sqlite.php
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Original file line number Diff line number Diff line change
Expand Up @@ -4579,8 +4579,9 @@ private function translate_token( WP_MySQL_Token $token ): ?string {
$value = substr( $value, 2, -1 );
}

// Convert the binary string to HEX.
$hex = base_convert( $value, 2, 16 );
// Convert the binary string to HEX. An empty value stays empty,
// as "base_convert()" would return "0" for it.
$hex = '' === $value ? '' : base_convert( $value, 2, 16 );
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/*
* The "base_convert()" function doesn't add or preserve padding.
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42 changes: 42 additions & 0 deletions packages/mysql-on-sqlite/tests/WP_MySQL_On_SQLite_Tests.php
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Original file line number Diff line number Diff line change
Expand Up @@ -11997,6 +11997,48 @@ public static function oddLengthQuotedHexadecimalLiterals(): array {
);
}

public function testEmptyBitLiteral(): void {
// An empty bit-value literal is an empty binary string, like an empty
// hex literal, and not the one-byte value "x'0'". See #612.
$this->assertEquals(
$this->assertQuery( "SELECT x'' AS v" ),
$this->assertQuery( "SELECT b'' AS v" )
);
$this->assertEquals(
array( (object) array( 'length' => '0' ) ),
$this->assertQuery( "SELECT LENGTH(b'') AS length" )
);

$this->assertQuery( 'CREATE TABLE t (id INT PRIMARY KEY, data BLOB)' );
$this->assertQuery( "INSERT INTO t (id, data) VALUES (1, b'')" );
$this->assertEquals(
array(
(object) array(
'id' => '1',
'data' => '',
),
),
$this->assertQuery( 'SELECT id, HEX(data) AS data FROM t' )
);
}

public function testEmptyBitLiteralComparesLikeEmptyHexLiteral(): void {
// Hex and bit literals translate to blob literals, and a blob never
// equals a text value in SQLite. MySQL compares the empty binary
// string equal to the empty text string, a difference tracked for
// hex literals in #575. The empty bit literal behaves like the empty
// hex literal, in both directions.
$this->assertEquals(
$this->assertQuery( "SELECT x'' = '' AS v" ),
$this->assertQuery( "SELECT b'' = '' AS v" )
);

$this->assertEquals(
array( (object) array( 'v' => '1' ) ),
$this->assertQuery( "SELECT b'' = x'' AS v" )
);
}

public function testColumnInfo(): void {
$this->assertQuery(
'CREATE TABLE t (
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