Bug #81635 [Nab->Opn]: When curly braces are escaped, the back-slash isn't removed \{

Edit report at https://bugs.php.net/bug.php?id=81635&edit=1 ID: 81635 Updated by: cmb@php.net Reported by: shealavington at gmail dot com Summary: When curly braces are escaped, the back-slash isn't removed \{ -Status: Not a bug +Status: Open Type: Bug Package: Scripting Engine problem Operating System: Windows 10 PHP Version: 8.0.12 Assigned To: cmb Block user comment: N Private report: N New Comment: Yeah, this is actually unclear. "hello\{$foo}" This looks like complex string interpolation syntax, but is apparently parsed as simple string interpolation syntax, so $foo is being replaced with its value. So, I assume, that the backslash acts as escape for the open *and* the closing curly braces. Previous Comments: ------------------------------------------------------------------------ [2021-11-18 11:31:29] shealavington at gmail dot com Notice how with this example I actually get one output with curlys and one without, which would suggest to me that there is a bug in the template parsing. ``` $foo = "bar"; var_dump("hello\{$foo}"); var_dump("hello\x{$foo}x"); ``` ------------------------------------------------------------------------ [2021-11-18 11:26:47] shealavington at gmail dot com I now see that \{ is not an escape sequence. However, that doesn't explain why the following ``` $foo = "bar"; var_dump("hello\{$foo}"); ``` outputs "hello\{bar}" instead of "hello\bar"... The curly braces should act as a variable wrap and should therefore be removed? Please do correct me if I'm mis-understanding here. ------------------------------------------------------------------------ [2021-11-18 11:21:24] cmb@php.net The docs do not list \$ as escape sequence[1]. They are actually very explicit about that[2]: | Since { can not be escaped, […] What you're looking for is <https://3v4l.org/hndfP>. [1] <https://www.php.net/manual/en/language.types.string.php#language.types.string.syntax.double> [2] <https://www.php.net/manual/en/language.types.string.php#language.types.string.parsing.complex> ------------------------------------------------------------------------ [2021-11-18 11:06:06] shealavington at gmail dot com Description: ------------ When curly braces are escaped within a string "", the back-slash isn't removed \{. For example "hello\{$foo}" is outputting hello\{bar} instead of hello{bar} Test script: --------------- <?php $foo = "bar"; $test_script = "hello\{$foo}" //- Explanation output below. echo "If \ is the escape character, why are the escaped characters and the escape character both shown?<br>"; echo "Res: <b>c:\path\hello\{$foo}</b><br>"; echo "Expected: <b>c:\path\hello"."{"."$foo}</b><br>"; echo "<br>Notice how in this example, I haven't used a \ but the {} characters are gone when not escaped?<br>"; echo "Res: <b>c:\path\hello{$foo}</b><br>"; echo "<br>If I use \ n, it replaces the \, I don't see \ n like I do in the first example above.<br>"; echo "Res: <b>c:\path\hello\note\{$foo}</b><br>"; Expected result: ---------------- hello{bar} Actual result: -------------- hello\{bar} ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=81635&edit=1