Adds two undocumented v: variables: _null_list and _null_dict because I do not
know a reproducible way to get such lists (though I think I heard about this)
and dictionaries (do not remember hearing about them). NULL strings are obtained
using $XXX_UNEXISTENT_VAR_XXX.
Fixes crash in json_encode($XXX_UNEXISTENT_VAR_XXX). Other added tests worked
fine before this commit.
Also removes a note regarding the performance of `empty(long_list)` vs
`len(long_list) == 0` because this has nothing to do with the actual state:
first checks that list is not NULL and pointer to its first element is also not
NULL, second gets length by comparing list with NULL and falls back to
`tv->vval.v_list->lv_len` if not. `len(long_list)` *may* still be *slightly*
slower, but the slow down has nothing to do with the length of the list, is
hardly noticeable and depends on how good compiler is at inlining and what
exactly have author of the plugin written (I mean `len(long_list) == 0` vs
`empty(long_list)` vs `!len(long_list)`).
Compiler used by one VM in QuickBuild has found a number of false positives.
Everything is fine on travis.
List of failures:
From [QuickBuild][1], build [7429][2]:
14:38:19,945 WARN - /home/quickbuild/buildagent/workspace/root/neovim/pull-requests-automated/src/nvim/eval.c: In function ‘assert_bool’:
14:38:19,945 WARN - /home/quickbuild/buildagent/workspace/root/neovim/pull-requests-automated/src/nvim/eval.c:7551:40: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]
14:38:20,058 WARN - cc1: all warnings being treated as errors
. This is not making much sense (7551:40 is `!=` in `{SpecialVarValue} !=
({bool}?{SpecialVarValue}:{SpecialVarValue})`), but this error is present.
---
Also fail from [build][3] [4930][4]:
15:47:00,853 WARN - /home/quickbuild/buildagent/workspace/root/neovim/pull-requests-automated/src/nvim/eval/encode.c: In function ‘encode_read_from_list’:
15:47:00,853 WARN - /home/quickbuild/buildagent/workspace/root/neovim/pull-requests-automated/src/nvim/eval/encode.c:258:30: error: conversion to ‘char’ from ‘int’ may alter its value [-Werror=conversion]
, pointing to `:` in `{char} = ({char} == {const} ? {const} : {char})` where
`{const}` is character constant like `'\n'`. I have no idea where exactly it saw
conversion, so simply casted everything to (char).
---
[Build][5] error:
08:32:03,472 WARN - /home/quickbuild/buildagent/workspace/root/neovim/pull-requests-automated/src/nvim/eval.c: In function ‘tv_equal’:
08:32:03,472 WARN - /home/quickbuild/buildagent/workspace/root/neovim/pull-requests-automated/src/nvim/eval.c:5077:1: error: control reaches end of non-void function [-Werror=return-type]
---
Build [4949][7]:
11:28:00,578 WARN - /home/quickbuild/buildagent/workspace/root/neovim/pull-requests-automated/src/nvim/eval.c: In function ‘f_type’:
11:28:00,578 WARN - /home/quickbuild/buildagent/workspace/root/neovim/pull-requests-automated/src/nvim/eval.c:16085:24: error: ‘n’ may be used uninitialized in this function [-Werror=uninitialized]
11:28:00,581 WARN - /home/quickbuild/buildagent/workspace/root/neovim/pull-requests-automated/src/nvim/eval.c: In function ‘f_empty’:
11:28:00,581 WARN - /home/quickbuild/buildagent/workspace/root/neovim/pull-requests-automated/src/nvim/eval.c:8505:24: error: ‘n’ may be used uninitialized in this function [-Werror=uninitialized]
[1]: http://neovim-qb.szakmeister.net/wicket/page?5-1.ILinkListener-content-buildTab-panel-masterStep-body-children-0-step-body-children-2-body-children-3-step-body-children-0-step-body-children-0-step-head-logLink
[2]: http://neovim-qb.szakmeister.net/build/4929
[3]: http://neovim-qb.szakmeister.net/build/4930
[4]: http://neovim-qb.szakmeister.net/wicket/page?1-1.ILinkListener-content-buildTab-panel-masterStep-body-children-0-step-body-children-1-body-children-3-step-body-children-0-step-body-children-0-step-head-logLink
[5]: http://neovim-qb.szakmeister.net/build/4948/step_status
[7]: http://neovim-qb.szakmeister.net/build/4949
