It's not super clear what $SHLVL is useful for, but the current
definition is essentially
"number of shells in the parent processes + 1"
which isn't *super useful*?
Bash's behavior here is a bit weird in that it increments $SHLVL
basically always, but since it auto-execs the last process it will
decrement it again, so in practice it's often not incremented.
E.g.
```
> echo $SHLVL
1
> bash -c 'echo $SHLVL; bash'
2
>> echo $SHLVL
2
```
Both bashes here end up having the same $SHLVL because this is
equivalent to `echo $SHLVL; exec bash`. Running `echo $SHLVL` and then
`bash -c 'echo $SHLVL'` in an interactive bash will have a different
result (1 and 2) because that doesn't *exec* the inner bash.
That's not something we want to get into, so what we do is increment
$SHLVL in every interactive fish. Non-interactive fish will simply
import the existing value.
That means if you had e.g. a bash that runs a fish script that ends up
opening a new fish session, you would have a $SHLVL of *2* - one for the
bash, and one for the inner fish.
We key this off is_interactive_session() (which can also be enabled
via `fish -i`) because it's easy and because `fish -i` is asking for
fish to be, in some form, "interactive".
That means most of the time $SHLVL will be "how many shells am I deep,
how often do I have to `exit`", except for when you specifically asked
for a fish to be "interactive". If that's a problem, we can rethink it.
Fixes#7864.
builtin_set_query returns the number of missing variables. Because the
return value passed to the shell is an 8-bit unsigned integer, if the
number of missing variables is a multiple of 256, it would overflow to 0.
This commit saturates the return value at 255 if there are more than 255
missing variables.
Variables like $status and $history showed up in all scopes, including
universal, when querying with `set -q` or `set -S`.
This makes it so they all only count as set in global scope, because
we already only allow assignment to electric variables in global scope.
Fixes#7032
Changes it from
```
$fish_color_user: not set in local scope
$fish_color_user: set in global scope, unexported, with 1 elements
$fish_color_user[1]: length=3 value=|080|
$fish_color_user: set in universal scope, unexported, with 1 elements
$fish_color_user[1]: length=7 value=|brgreen|
```
(with the trailing empty line - not just a newline)
to
```
$fish_color_user: set in global scope, unexported, with 1 elements
$fish_color_user[1]: |080|
$fish_color_user: set in universal scope, unexported, with 1 elements
$fish_color_user[1]: |brgreen|
```
It's now good enough to do so.
We don't allow grid-alignment:
```fish
complete -c foo -s b -l barnanana -a '(something)'
complete -c foo -s z -a '(something)'
```
becomes
```fish
complete -c foo -s b -l barnanana -a '(something)'
complete -c foo -s z -a '(something)'
```
It's just more trouble than it is worth.
The one part I'd change:
We align and/or'd parts of an if-condition with the in-block code:
```fish
if true
and false
dosomething
end
```
becomes
```fish
if true
and false
dosomething
end
```
but it's not used terribly much and if we ever fix it we can just
reindent.
Universal exported variables (created by `set -xU`) used to show up
both as universal and global variable in child instances of fish.
As a result, when changing an exported universal variable, the
new value would only be visible after a new login (or deleting the
variable from global scope in each fish instance).
Additionally, something like `set -xU EDITOR vim -g` would be imported
into the global scope as a single word resulting in failures to
execute $EDITOR in fish.
We cannot simply give precedence to universal variables, because
another process might have exported the same variable. Instead, we
only skip importing a variable when it is equivalent to an exported
universal variable with the same name. We compare their values after
joining with spaces, hence skipping those imports does not change the
environment fish passes to its children. Only the representation in
fish is changed from `"vim -g"` to `vim -g`.
Closes#5258.
This eliminates the issue #5348 for universal variables.
This test uses universal variables, and so it can fail when run
multiple times.
It might be a good idea to do this in general, but for now let's just
try it here.
