handle unexpected args to binding mode functions

Fixes #3472

share/functions/__fish_shared_key_bindings.fish

@@ -3,7 +3,14 @@ function __fish_shared_key_bindings -d "Bindings shared between emacs and vi mod
     # They are supposed to be unrelated to text-editing (or movement).
     # This takes $argv so the vi-bindings can pass the mode they are valid in.
 
+    if contains -- -h $argv
+        or contains -- --help $argv
+        echo "Sorry but this function doesn't support -h or --help"
+        return 1
+    end
+
     bind $argv \cy yank
+    or return  # protect against invalid $argv
     bind $argv \ey yank-pop
 
     # Left/Right arrow
@@ -81,10 +88,11 @@ function __fish_shared_key_bindings -d "Bindings shared between emacs and vi mod
     bind $argv -k f1 __fish_man_page
     bind $argv \eh __fish_man_page
 
-    # This will make sure the output of the current command is paged using the default pager when you press Meta-p.
+    # This will make sure the output of the current command is paged using the default pager when
+    # you press Meta-p.
     # If none is set, less will be used.
     bind $argv \ep '__fish_paginate'
-    
+
     # Make it easy to turn an unexecuted command into a comment in the shell history. Also,
     # remove the commenting chars so the command can be further edited then executed.
     bind $argv \e\# __fish_toggle_comment_commandline

share/functions/fish_default_key_bindings.fish

@@ -1,4 +1,10 @@
 function fish_default_key_bindings -d "Default (Emacs-like) key bindings for fish"
+    if contains -- -h $argv
+        or contains -- --help $argv
+        echo "Sorry but this function doesn't support -h or --help"
+        return 1
+    end
+
     if not set -q argv[1]
         # Clear earlier bindings, if any
         bind --erase --all
@@ -6,16 +12,20 @@ function fish_default_key_bindings -d "Default (Emacs-like) key bindings for fis
             # Allow the user to set the variable universally
             set -q fish_key_bindings
             or set -g fish_key_bindings
-            set fish_key_bindings fish_default_key_bindings # This triggers the handler, which calls us again and ensures the user_key_bindings are executed
+            # This triggers the handler, which calls us again and ensures the user_key_bindings
+            # are executed.
+            set fish_key_bindings fish_default_key_bindings
             return
         end
     end
 
     # These are shell-specific bindings that we share with vi mode.
     __fish_shared_key_bindings $argv
+    or return  # protect against invalid $argv
 
     # This is the default binding, i.e. the one used if no other binding matches
     bind $argv "" self-insert
+    or exit  # protect against invalid $argv
 
     bind $argv \n execute
     bind $argv \r execute

share/functions/fish_vi_key_bindings.fish

@@ -1,4 +1,10 @@
 function fish_vi_key_bindings --description 'vi-like key bindings for fish'
+    if contains -- -h $argv
+        or contains -- --help $argv
+        echo "Sorry but this function doesn't support -h or --help"
+        return 1
+    end
+
     # Erase all bindings if not explicitly requested otherwise to
     # allow for hybrid bindings.
     # This needs to be checked here because if we are called again
@@ -16,7 +22,9 @@ function fish_vi_key_bindings --description 'vi-like key bindings for fish'
         # Allow the user to set the variable universally
         set -q fish_key_bindings
         or set -g fish_key_bindings
-        set fish_key_bindings fish_vi_key_bindings # This triggers the handler, which calls us again and ensures the user_key_bindings are executed
+        # This triggers the handler, which calls us again and ensures the user_key_bindings
+        # are executed.
+        set fish_key_bindings fish_vi_key_bindings
         return
     end