Commit ec3d3a481 (Support "$(cmd)" command substitution without line
splitting, 2021-07-02) started treating an input string like
"a$()b" as if it were "a"$()"b". Yet, we do not actually insert the
virtual quotes. Instead we just adapted the definition of when quotes
are closed - hence the changes to quote_end().
parse_util_locate_cmdsubst_range() is aware
of the changes to quote_end() but some of its
callers like parse_util_detect_errors_in_argument() and
highlighter_t::color_as_argument() are not. They split strings at
command substitution boundaries without handling the special quoting
rules. (Only the expansion logic did it right.)
Fix this by handling the special quoting rules inside
parse_util_locate_cmdsubst_range(). This is a bit hacky since it
makes it harder for callers to process some substrings in between
command substitutions, but that's okay because current callers only
care about what's inside the command substitutions.
Fixes#8394
This adds a hack to the parser. Given a command
echo "x$()y z"
we virtually insert double quotes before and after the command
substitution, so the command internally looks like
echo "x"$()"y z"
This hack allows to reuse the existing logic for handling (recursive)
command substitutions.
This makes the quoting syntax more complex; external highlighters
should consider adding this if possible.
The upside (more Bash compatibility) seems worth it.
Closes#159
