node-sass 4.9.0 (bumping libsass) caused a regression

[stefanpenner]

I have included a failing test, and bisect suggests the following commit:

7ec14df

7ec14dff2087266357146598cd267f4133f3fdf6 is the first bad commit
commit 7ec14dff2087266357146598cd267f4133f3fdf6
Author: xzyfer <xzyfer@gmail.com>
Date:   Wed Apr 25 01:56:30 2018 +1000

    Bump LibSass@3.5.3

:100644 100644 466e3ab638ea801dbb880d5b9b9de1263d0cf3bc 5c5972278855bc49f19c807f4f4343d9a6ca9b94 M      package.json
:040000 040000 f171af209130ad6c3528fb25fd65ea5cc952dc30 359c2cc77e49902cefae961592aba1270a1a144a M      src

Bisect log:

git bisect start
# good: [31abf973bd20d45c253d45f421fd8b3bcce0f92f] failure
git bisect good 31abf973bd20d45c253d45f421fd8b3bcce0f92f
# bad: [ac67c7ad14afc6545b193802d8d9271c3335fc84] failure
git bisect bad ac67c7ad14afc6545b193802d8d9271c3335fc84
# bad: [ac67c7ad14afc6545b193802d8d9271c3335fc84] failure
git bisect bad ac67c7ad14afc6545b193802d8d9271c3335fc84
# good: [b2df434a02c10b2263d3879fe75dfbed4460b75f] 4.8.3
git bisect good b2df434a02c10b2263d3879fe75dfbed4460b75f
# good: [5e10a9b9df87db448374bd7e78ffb3ba2699aff6] 4.9.0
git bisect good 5e10a9b9df87db448374bd7e78ffb3ba2699aff6
# bad: [a124e9d42e1f5bdb0a96fca78435c889e6e2b41f] Add Node 10 to CI
git bisect bad a124e9d42e1f5bdb0a96fca78435c889e6e2b41f
# bad: [7ec14dff2087266357146598cd267f4133f3fdf6] Bump LibSass@3.5.3
git bisect bad 7ec14dff2087266357146598cd267f4133f3fdf6
# good: [eb5ad0a7b8b98a35d752c3dea3573c5fb491be8e] Revert "Bump LibSass@3.5.3 (#2342)"
git bisect good eb5ad0a7b8b98a35d752c3dea3573c5fb491be8e
# first bad commit: [7ec14dff2087266357146598cd267f4133f3fdf6] Bump LibSass@3.5.3

[stefanpenner]

specifically in 4.8.3 this is not null, but in 4.9.0 this becomes null

[stefanpenner]

Some Areas of interest in the offending commit:

• 7ec14df#diff-48705ae5ffc823a6dd0b8d857283bb5cL1266
• 7ec14df#diff-46ac35a7e695d6f61048e56e79b0a675R1631
• 7ec14df#diff-46ac35a7e695d6f61048e56e79b0a675L1673
• 7ec14df#diff-46ac35a7e695d6f61048e56e79b0a675R2706

Libsass:

• sass/libsass@72e9a04#diff-71cf018f7c4c4dc52791eb53a9d0f6eb

[stefanpenner]

Speaking with @chriseppstein he suggests this may not be a bug, rather a longstanding bugfix in the libsass implementation.

[stefanpenner]

I wonder if in the spirit of "least pain" this bump of libsass should be a major bump in node-sass.

[xzyfer]

You're correct this was an intentional bugfix with unintentional consequences. Closing this in favour of discussion in #2364