Some programs may output extra empty lines after the directive.
Those lines must be ignored for fish shell completion to work.
zsh and bash are not impacted.

Signed-off-by: Marc Khouzam <marc.khouzam@montreal.ca>
Co-authored-by: Johannes Altmanninger <aclopte@gmail.com>

Co-authored-by: Johannes Altmanninger <aclopte@gmail.com>

Make sure to filter the returned completions before we check if
there are valid completions left.

Fixes #1362

Signed-off-by: Paul Holzinger <paul.holzinger@web.de>

Flag definitions like `-asd` are not handled correctly by
the custom completion logic. They should be treated as
multiple flags. For details refer to #1257.

Fixes #1257

Signed-off-by: Paul Holzinger <paul.holzinger@web.de>

Fixes #1211

When handling ShellCompDirectiveNoSpace we must still properly handle
descriptions.  To do so we cannot simply use 'compadd', but must use
zsh's '_describe' function.

Also, when handling ShellCompDirectiveNoSpace we cannot assume that
only a single completion will be given to the script.  In fact,
ValidArgsFunction can return multiple completions, even if they don't
match the 'toComplete' argument prefix.  Therefore, we cannot use the
number of completions received in the completion script to determine
if we should activate the "no space" directive.  Instead, we can leave
it all to the '_describe' function.

Fixes #1212

When handling ShellCompDirectiveNoFileComp we cannot base ourself on
the script receiving no valid completion. In fact,
ValidArgsFunction can return multiple completions, even if they don't
match the 'toComplete' argument prefix at all.  Therefore, we cannot use
the number of completions received by the completion script to determine
if we should activate the "no file comp" directive.  Instead, we can
check if the '_describe' function has found any completions.

Finally, it is important for the script to return the return code of the
called zsh functions (_describe, _arguments).  This tells zsh if
completions were found or not, which if not, will trigger different
matching attempts, such as matching what the user typed with the the
content of possible completions (instead of just as the prefix).

Signed-off-by: Marc Khouzam <marc.khouzam@montreal.ca>

* Fix fish for ShellDirectiveNoSpace and file comp

For fish shell we achieve ShellDirectiveNoSpace by outputing a fake
second completion with an extra character.  However, this extra
character was being added after the description string, instead of
before.  This commit fixes that.

It also cleans up the script of useless code, now that fish completion
details are better understood.

Signed-off-by: Marc Khouzam <marc.khouzam@montreal.ca>

* Handle case when completion starts with a space

Fixes #1303

Signed-off-by: Marc Khouzam <marc.khouzam@montreal.ca>

* Support fish completion with env vars in the path

Fixes #1214
Fixes #1306

Signed-off-by: Marc Khouzam <marc.khouzam@montreal.ca>

* Update based on review

1- We use `set -l` for local variable to make sure there are no
   conflicts with global variables
2- We use `commandline -opc` which:
   a) splits the command line into tokens (-o)
   b) only considers the current command (-p) (e.g., echo hello; helm <TAB>)
   c) stops at the cursor (-c)
3- We extract the last arg with `commandline -ct` and escape it to handle
   the case where it is a space, or unmatched quote.
4- We avoid looping when filtering on prefix.
5- We don't add a fake comp for ShellCompDirectiveNoSpace when the
   completion ends with any of @=/:., as fish won't add a space

Signed-off-by: Marc Khouzam <marc.khouzam@montreal.ca>