Chained modifiers, unexpected results.

[P-a-d-r-a-i-g]

The first case below comes from a Smarty2 script which works fine, but once applied to Smarty3.1.x and up it breaks giving an unexpected value.

The issue stems from the -4 being used in substr and the cat after it. If the - sign is removed, the functions works as expected, albeit the other way around.

Is this a Smarty bug?

The following is a simple test script with expected and actual results.

{assign var="aFile" value="somefile.xyz"|substr:0:-4|cat:".ext"}
<!-- Result expected: somefile.ext -->
<!-- Actual result: somefile -->
{$aFile}

{assign var="aFile" value="somefile.xyz"|substr:0:4|cat:".ext"}
<!-- Result expected: some.ext -->
<!-- Actual result: some.ext -->
{$aFile}

{assign var="aFile" value=("somefile.xyz"|substr:0:-4)|cat:".ext"}
<!-- Result expected: somefile.ext -->
<!-- Actual result: somefile.ext -->
{$aFile}

{assign var="aFile" value="somefile.xyz"|substr:0:-4}
{assign var="aFile" value=$aFile|cat:".ext"}
<!-- Result expected: somefile.ext -->
<!-- Actual result: somefile.ext -->
{$aFile}

{assign var="aFile" value="somefile.xyz"|substr:0:-(4)|cat:".ext"}
<!-- Result expected: somefile.ext -->
<!-- Actual result: somefile -->
{$aFile}

{assign var="aFile" value="somefile.xyz"|substr:0:(-4)|cat:".ext"}
<!-- Result expected: somefile.ext -->
<!-- Actual result: somefile.ext -->
{$aFile}

{assign var="aFile" value=-4|cat:".ext"}
<!-- Result expected: -4.ext -->
<!-- Actual result: -4.ext -->
{$aFile}

{assign var="aFile" value=-4-4|cat:".ext"}
<!-- Result expected: -8.ext -->
<!-- Actual result: -8.ext -->
{$aFile}

Above code contained here:
test.tpl.txt

[P-a-d-r-a-i-g]

In the compiled tpl, the first case is compiled as:

$_smarty_tpl->_assignInScope('aFile', substr("somefile.xyz",0,-(4).(".ext")));

We can see from this that -(4).(".ext") is trying to be used as the 3rd parameter of substr which is not what is expected and used to work fine with Smarty2.

[P-a-d-r-a-i-g]

I've attached the whole compiled tpl of the test script above for reference

compiled.file.test.tpl.php.txt

[AnrDaemon]

Any results of modifying an assignment is an undefined behavior.
Please do not do that. Better yet, do not use assignments in templates if at all possible.

[AnrDaemon]

If you absolutely want to do it, please try the v3 syntax {$name=value}.

[uwetews]

This is a bug on chained modifier when last modifier parameter is a signed value. I will fix that asap

[uwetews]

AnrDaemon
It has nothing to do with the assign tag

[uwetews]

The bugfix is now in the master branch and will later be included in 3.1.22