Segmentation fault on undefined mixin

[paazmaya]

With the latest dev version stack of grunt-sass, node-sass, libsass and sass2scss, once a mixin that does not exist is used, the following segmentation fault occurs:

PID 2574 received SIGSEGV for address: 0x0
0   segfault-handler-native.node        0x00000001009f1b78 _ZL16segfault_handleriP9__siginfoPv + 192
1   libsystem_platform.dylib            0x00007fff972ee5aa _sigtramp + 26
2   ???                                 0x000000000000000d 0x0 + 13
3   node                                0x000000010014cf7c _ZN2v86String3NewEPKci + 214
4   binding.node                        0x0000000103f48ea1 _Z12FillStatsObjN2v86HandleINS_6ObjectEEEP17sass_file_context + 42
5   binding.node                        0x0000000103f48fca _Z12MakeCallbackP9uv_work_s + 136
6   node                                0x0000000100138eb0 uv__work_done + 168
7   node                                0x000000010012fcfd uv__async_event + 62
8   node                                0x000000010012fe70 uv__async_io + 136
9   node                                0x000000010013c7be uv__io_poll + 1427
10  node                                0x00000001001302b5 uv_run + 239
11  node                                0x000000010000c01e _ZN4node5StartEiPPc + 365
12  node                                0x00000001000030f4 start + 52
13  ???                                 0x0000000000000003 0x0 + 3

With a minimal example the error is handled properly, with a message that the given mixin is undefined.
However with my "massive" Sass code this happens. I will try to extract a minimal example where this occurs.

[paazmaya]

The following Sass:

=query
  @media screen
    @content

.selector-with-dash
  +query
    p
      color: rebeccapurple
      +doesnotexist

.selector
  text-decoration-color: blue

The failure "might" be related to source maps, as changing that option creates a different error as show below. Both examples are run via grunt-sass.

Files: undefined-mixin.sass -> undefined-mixin.css
Options: precision=10, sourceComments="map", sourceMap
PID 23404 received SIGSEGV for address: 0x0
0   segfault-handler-native.node        0x00000001009f1b78 _ZL16segfault_handleriP9__siginfoPv + 192
1   libsystem_platform.dylib            0x00007fff972ee5aa _sigtramp + 26
2   ???                                 0x000000000000000d 0x0 + 13
3   node                                0x000000010014cf7c _ZN2v86String3NewEPKci + 214
4   binding.node                        0x0000000103fcbea1 _Z12FillStatsObjN2v86HandleINS_6ObjectEEEP17sass_file_context + 42
5   binding.node                        0x0000000103fcbfca _Z12MakeCallbackP9uv_work_s + 136
6   node                                0x0000000100138eb0 uv__work_done + 168
7   node                                0x000000010012fcfd uv__async_event + 62
8   node                                0x000000010012fe70 uv__async_io + 136
9   node                                0x000000010013c7be uv__io_poll + 1427
10  node                                0x00000001001302b5 uv_run + 239
11  node                                0x000000010000c01e _ZN4node5StartEiPPc + 365
12  node                                0x00000001000030f4 start + 52
13  ???                                 0x0000000000000004 0x0 + 4

Files: undefined-mixin.sass -> undefined-mixin.css
Options: precision=10, sourceComments="map", sourceMap=false
Assertion failed: (val->IsString()), function _NanGetExternalParts, file ../node_modules/nan/nan.h, line 1990.
Abort trap: 6

[paazmaya]

With inline comments, the given and expected output appears:

Files: undefined-mixin.sass -> undefined-mixin.css
Options: precision=10, sourceComments="inline", sourceMap
Warning: undefined-mixin.sass:9: error: no mixin named doesnotexist
Backtrace:
    undefined-mixin.sass:9, in mixin `@content`
    undefined-mixin.sass:3, in mixin `query`
    undefined-mixin.sass:6
 Use --force to continue.

[paazmaya]

Even a small Sass as this triggers the above described behaviour:

.selector
  color: rebeccapurple
  +doesnotexist

[akhleung]

I'm not able to reproduce the error when running LibSass on its own ... given the various other segfaults that have been occurring with Node-Sass (which I can't reproduce when running LibSass standalone), I'm starting to think that there might be something wrong with how they're handling LibSass errors....

[paazmaya]

Thanks for the tip, will look at node-sass more in depth.

[am11]

I tend to believe that I have fixed this issue via:

• Code: Rescue from Segmentation Fault (#361) node-sass#366 and
• Code: Rescue from throwing (#362) node-sass#367

Those PRs are awaiting review / merge.

[paazmaya]

Indeed, sass/node-sass#366 seems to fix this issue and results in showing better message about the non existing mixin.
Thank you @am11