For implementation reasons, we special-case cd in several ways
1. it gets different completions (handle_as_special_cd)
2. when highlighting, we honor CDPATH
3. we discard autosuggestions from history that don't have valid path arguments
There are some third-party tools like zoxide that redefine cd ("function cd
--wraps ...; ...; end"). We can't support this in general but let's try to
make an effort.
zoxide tries to be a superset of cd, so special case 1 is still
valid but 2 and 3 are not, because zoxide accepts some paths
that cd doesn't accept.
Let's add a hack to detect when "cd" actually means something else by checking
if there is any --wraps argument.
A cleaner solution is definitely possible but more effort.
Closes#10719
Given "1(23)4", this function returns an inclusive range, from the opening
to the closing parenthesis. The subcommand is extracted by incrementing
the range start and interpreting the result as an exclusive range.
This is confusing, especially if we want to add multi-character quotes.
Change it to always return the full range (including parentheses) and provide
an easy way to access the command string.
While at it, switch to returning an enum.
This change is perhaps larger and more complex than necessary (sorry)
because it is mainly made with multi-character quotes in mind. Let's see
if that works out.
This allows making something like
```fish
abbr --add gc --position anywhere --command git back 'reset --hard
HEAD^'
```
to expand "gc" to "reset --hard HEAD^", but only if the command is
git (including "command git gc" or "and git gc").
Fixes#9411
This tries to open the given file to use as stdin, and if it fails,
for any reason, it uses /dev/null instead.
This is useful in cases where we would otherwise do either of these:
```fish
test -r /path/to/file
and string match foo < /path/to/file
cat /path/to/file 2>/dev/null | string match foo
```
This both makes it nicer and shorter, *and* helps with TOCTTOU - what if the file is removed/changed after the check?
The reason for reading /dev/null instead of a closed fd is that a closed fd will often cause an error.
In case opening /dev/null fails, it still skips the command.
That's really a last resort for when the operating system
has turned out to be a platypus and not a unix.
Fixes#4865
(cherry picked from commit df8b9b7095)
