node-sass crashes when a parent selector is referenced but not included

[slyoldfox]

When testing the latest node-sass@3.4.0-beta1 on our code base, node-sass plain crashes.

I traced it to the following (invalid code):

$common-border: "foo";
.nihilo & {
  .dijitMenu {
    border: $common-border;
    .dijitMenuItem {
      color: getColor('text-dark-main');
    }
  }
}

This seems to happen when a parent selector is referenced (the ampersand behind the .nihilo), but the parent node does not exist. node-sass/libsass should at least throw some kind of error. Now the process just seems to crash.

Following is the output on my system:

c:\Code\site2014\static\gulpfile.js build:scss --source file.scss
[15:49:13] Using gulpfile gulpfile.js
[15:49:13] Starting 'scss:options'...
[15:49:13] Using version: node-sass 3.4.0-beta1 (Wrapper) [JavaScript]
libsass 3.3.0-beta2 (Sass Compiler) [C/C++]
[15:49:13] Finished 'scss:options' after 1.19 ms
[15:49:13] Starting 'scss:compile'...
[15:49:13] [scss] : sync / expanded mode.
[15:49:13] [scss:compile] [1] [c:\file.scss]

Process finished with exit code -1073741819 (0xC0000005)

[slyoldfox]

@xzyfer would love if this could make it in the 3.3 release

[slyoldfox]

The following is a more complex example with a mixin

$tablet-portrait:                 768px;
$tablet-landscape:                980px;
$desk-normal:                     1120px;
$desk-big:                        1280px;
$grid-breakpoints-immobile: (
        'tablet-portrait':   '(min-width: ' + $tablet-portrait + ') and (max-width: ' + $tablet-landscape + ')',
        'tablet-landscape':  '(min-width: ' +  $tablet-landscape + ') and (max-width: ' + $desk-normal + ')',
        'desk-normal':       '(min-width: ' +  $desk-normal + ') and (max-width: ' + $desk-big + ')',
        'desk-big':          '(min-width: ' +  $desk-big + ')'
);
@mixin grid-media-query($media-query, $breakpointDefinitions) {
  $breakpoint-found: false;

  @each $breakpoint, $breakpointvalue in $breakpointDefinitions{
    $name: $breakpoint;
    $declaration: $breakpointvalue;

    @if $media-query == $name and $declaration{
      $breakpoint-found: true;

      @media only screen and #{$declaration} {
        @content;
      }
    }
  }
}

@each $name in map-keys($grid-breakpoints-immobile) {
  @include grid-media-query($name, $grid-breakpoints-immobile) {
    body.immobile & {
      margin-bottom: 0;
    }
  }
}

Output on 3.3.3:

$ node-sass file.scss
@media only screen and (min-width: 768px) and (max-width: 980px) {
  body.immobile {
    margin-bottom: 0; } }

@media only screen and (min-width: 980px) and (max-width: 1120px) {
  body.immobile {
    margin-bottom: 0; } }

@media only screen and (min-width: 1120px) and (max-width: 1280px) {
  body.immobile {
    margin-bottom: 0; } }

@media only screen and (min-width: 1280px) {
  body.immobile {
    margin-bottom: 0; } }

On 3.4.0

$ node-sass -v
node-sass       3.4.0-beta1     (Wrapper)       [JavaScript]
libsass         3.3.0-beta2     (Sass Compiler) [C/C++]

$ node-sass file.scss
/c/Users/marc/AppData/Roaming/npm/node-sass: line 14:  7024 Segmentation fault      node "$basedir/node_modules/node-sass/bin/node-sass" "$@"

[saper]

Here's what I got with the brand new libsass:

m> ~/sw/sassc/bin/sassc -v
sassc: 3.3.0-beta1
libsass: 3.3.0-beta2-1-g1efd
sass2scss: 1.0.3
m> ~/sw/sassc/bin/sassc spec/libsass-todo-issues/issue_1569/input.scss
Error: Base-level rules cannot contain the parent-selector-referencing character '&'.

       Backtrace:
                spec/libsass-todo-issues/issue_1569/input.scss:2
        on line 2 of spec/libsass-todo-issues/issue_1569/input.scss
>> .nihilo & {
   --------^

[saper]

Crash backtrace for the complex case:

Program received signal SIGSEGV, Segmentation fault.
0x000000000047af9d in Sass::Complex_Selector::skip_empty_reference (this=0x801c502e0) at src/ast.hpp:2128
2128            tail_->has_line_feed_ = this->has_line_feed_;
(gdb) bt
#0  0x000000000047af9d in Sass::Complex_Selector::skip_empty_reference (this=0x801c502e0) at src/ast.hpp:2128
#1  0x0000000000463433 in Sass::Complex_Selector::parentize (this=0x801c36020, parents=0x0, ctx=...) at src/ast.cpp:955
#2  0x00000000004626bd in Sass::Complex_Selector::parentize (this=0x801c34f60, parents=0x0, ctx=...) at src/ast.cpp:890
#3  0x0000000000528a8c in Sass::Eval::operator() (this=0x7fffffffde20, s=0x801c34f60) at src/eval.cpp:1426
#4  0x0000000000528624 in Sass::Eval::operator() (this=0x7fffffffde20, s=0x801c31200) at src/eval.cpp:1399
#5  0x0000000000481ae1 in Sass::Selector_List::perform (this=0x801c31200, op=0x7fffffffde20) at src/ast.hpp:2275
#6  0x000000000053f511 in Sass::Expand::operator() (this=0x7fffffffde10, r=0x801c34ec0) at src/expand.cpp:117
#7  0x000000000047cc1e in Sass::Ruleset::perform (this=0x801c34ec0, op=0x7fffffffde10) at src/ast.hpp:413
#8  0x00000000005495c6 in Sass::Expand::append_block (this=0x7fffffffde10, b=0x801c31140) at src/expand.cpp:644
#9  0x0000000000548d69 in Sass::Expand::operator() (this=0x7fffffffde10, c=0x801c4c540) at src/expand.cpp:613
#10 0x000000000054f161 in Sass::Mixin_Call::perform (this=0x801c4c540, op=0x7fffffffde10) at src/ast.hpp:779
#11 0x00000000005494a5 in Sass::Expand::operator() (this=0x7fffffffde10, c=0x801c1c980) at src/expand.cpp:628
#12 0x000000000065b651 in Sass::Content::perform (this=0x801c1c980, op=0x7fffffffde10) at src/ast.hpp:789
#13 0x00000000005495c6 in Sass::Expand::append_block (this=0x7fffffffde10, b=0x801c30e40) at src/expand.cpp:644
#14 0x000000000053e58d in Sass::Expand::operator() (this=0x7fffffffde10, b=0x801c30e40) at src/expand.cpp:78
#15 0x00000000004faf8e in Sass::Block::perform (this=0x801c30e40, op=0x7fffffffde10) at src/ast.hpp:378
#16 0x00000000005409fd in Sass::Expand::operator() (this=0x7fffffffde10, m=0x801c347e0) at src/expand.cpp:182
#17 0x000000000047cebe in Sass::Media_Block::perform (this=0x801c347e0, op=0x7fffffffde10) at src/ast.hpp:457
#18 0x00000000005495c6 in Sass::Expand::append_block (this=0x7fffffffde10, b=0x801c30b40) at src/expand.cpp:644
#19 0x00000000005429b1 in Sass::Expand::operator() (this=0x7fffffffde10, i=0x801c34a60) at src/expand.cpp:352
#20 0x000000000065b471 in Sass::If::perform (this=0x801c34a60, op=0x7fffffffde10) at src/ast.hpp:624
#21 0x00000000005495c6 in Sass::Expand::append_block (this=0x7fffffffde10, b=0x801c30900) at src/expand.cpp:644
#22 0x0000000000544b13 in Sass::Expand::operator() (this=0x7fffffffde10, e=0x801c30f00) at src/expand.cpp:457
#23 0x000000000065b081 in Sass::Each::perform (this=0x801c30f00, op=0x7fffffffde10) at src/ast.hpp:654
#24 0x00000000005495c6 in Sass::Expand::append_block (this=0x7fffffffde10, b=0x801c30780) at src/expand.cpp:644
#25 0x0000000000548d69 in Sass::Expand::operator() (this=0x7fffffffde10, c=0x801c31080) at src/expand.cpp:613
#26 0x000000000054f161 in Sass::Mixin_Call::perform (this=0x801c31080, op=0x7fffffffde10) at src/ast.hpp:779
#27 0x00000000005495c6 in Sass::Expand::append_block (this=0x7fffffffde10, b=0x801c30fc0) at src/expand.cpp:644
#28 0x00000000005453c0 in Sass::Expand::operator() (this=0x7fffffffde10, e=0x801c31740) at src/expand.cpp:489
#29 0x000000000065b081 in Sass::Each::perform (this=0x801c31740, op=0x7fffffffde10) at src/ast.hpp:654
#30 0x00000000005495c6 in Sass::Expand::append_block (this=0x7fffffffde10, b=0x801c30180) at src/expand.cpp:644
#31 0x000000000053e58d in Sass::Expand::operator() (this=0x7fffffffde10, b=0x801c30180) at src/expand.cpp:78
#32 0x00000000004faf8e in Sass::Block::perform (this=0x801c30180, op=0x7fffffffde10) at src/ast.hpp:378
#33 0x00000000004c44d4 in Sass::Context::parse_file (this=0x801c23280) at src/context.cpp:352
#34 0x00000000004226c0 in sass_parse_block (compiler=0x801c060e0) at src/sass_context.cpp:481
#35 0x0000000000422501 in sass_compiler_parse (compiler=0x801c060e0) at src/sass_context.cpp:637
#36 0x0000000000421fc5 in sass_compile_context (c_ctx=0x801c1f100, cpp_opt=...) at src/sass_context.cpp:519
#37 0x0000000000422389 in sass_compile_file_context (file_ctx=0x801c1f100) at src/sass_context.cpp:624
#38 0x0000000000419f3f in compile_file (options=0x801c1c080, input_path=0x7fffffffeacf "spec/libsass-todo-tests/parent-selector/missing/input.scss", 
    outfile=0x0) at sassc.c:107

[slyoldfox]

Thanks for checking up on this and adding the test cases. I'm AWAL next week for two weeks. If you need someone to test this on our .scss files, @HeadOnAPlate might be able to run those while I'm gone.