fish_config: remove hardcoded set of colors to erase

This is incomplete, and we'll solve the problem differently. For now,
leave colors that are not mentioned in the theme.  This causes problems
for sparse themes, but a following commit will fix that by making
"fish_config theme choose" erase all variables set by a previous
invocation (but not erase variables set by the user).  Only webconfig
won't do that since it (historically) uses copy semantics, but we
could change that too if needed.

This also breaks the guarantee mentioned by this comment in webconfig:

> Ensure that we have all the color names we know about, so that if the
> user deletes one he can still set it again via the web interface

which should be fine because:
1. a following commit will always set all globals at interactive init,
   so colors should only be missing in edge cases ("fish -c fish_config").
2. it's easy to recover from by setting a default theme.

share/functions/__fish_color_variables.fish

@@ -1,38 +0,0 @@
-# localization: skip(private)
-function __fish_color_variables
-    printf %s "\
-fish_color_autosuggestion
-fish_color_cancel
-fish_color_command
-fish_color_comment
-fish_color_cwd
-fish_color_end
-fish_color_error
-fish_color_escape
-fish_color_host
-fish_color_host_remote
-fish_color_keyword
-fish_color_normal
-fish_color_operator
-fish_color_option
-fish_color_param
-fish_color_quote
-fish_color_redirection
-fish_color_search_match
-fish_color_selection
-fish_color_user
-fish_pager_color_background
-fish_pager_color_completion
-fish_pager_color_description
-fish_pager_color_prefix
-fish_pager_color_progress
-fish_pager_color_secondary_background
-fish_pager_color_secondary_completion
-fish_pager_color_secondary_description
-fish_pager_color_secondary_prefix
-fish_pager_color_selected_background
-fish_pager_color_selected_completion
-fish_pager_color_selected_description
-fish_pager_color_selected_prefix
-"
-end

share/functions/fish_config.fish

@@ -19,7 +19,6 @@ function fish_config --description "Launch fish's web based configuration"
         if set -l python (__fish_anypython)
             function __fish_config_webconfig -V python -a web_config
                 set -lx __fish_bin_dir $__fish_bin_dir
-                set -lx fish_color_variables "$(__fish_color_variables)"
                 $python $web_config/webconfig.py
             end
             __fish_data_with_directory tools/web_config '.*' __fish_config_webconfig
@@ -236,7 +235,6 @@ function __fish_config_theme_choose
         set scope -U
     end
 
-    set -l known_colors (__fish_color_variables)
     if not set -q argv[1]
         # We're persisting whatever current colors are loaded (maybe in the global scope)
         # to the universal scope, without overriding them from a theme file.
@@ -272,17 +270,6 @@ function __fish_config_theme_choose
             set $scope $toks
             set -a defined_colors $toks[1]
         end
-
-    # Set all colors that aren't mentioned to empty
-    for c in $known_colors
-        contains -- $c $defined_colors
-        and continue
-        # Erase conflicting global variables so we don't get a warning and
-        # so changes are observed immediately.
-        set -eg $c
-        set $scope $c
-    end
-
 end
 
 function __fish_config_theme_canonicalize --no-scope-shadowing

share/tools/web_config/webconfig.py

@@ -41,8 +41,6 @@ import webbrowser
 if term is not None:
     os.environ["TERM"] = term
 
-KNOWN_COLORS = set(os.environ["fish_color_variables"].splitlines())
-
 
 def find_executable(exe, paths=()):
     final_path = os.environ["PATH"].split(os.pathsep)
@@ -804,11 +802,6 @@ class FishConfigHTTPRequestHandler(SimpleHTTPServer.SimpleHTTPRequestHandler):
 
         colors.sort(key=operator.itemgetter("name"))
 
-        # Ensure that we have all the color names we know about, so that if the
-        # user deletes one he can still set it again via the web interface
-        for color_name in KNOWN_COLORS - {color["name"] for color in colors}:
-            add_color(color_name, "")
-
         info["colors"] = colors
         return info
 
@@ -1199,20 +1192,13 @@ class FishConfigHTTPRequestHandler(SimpleHTTPServer.SimpleHTTPRequestHandler):
 
         if p == "/set_color/":
             print("# Colorscheme: " + postvars.get("theme"))
-            have_colors = set()
             output = ""
             for item in postvars.get("colors"):
                 what = item.get("what")
                 color = item.get("color")
                 if what:
-                    have_colors.add(what)
                     output = self.do_set_color_for_variable(what, color)
 
-            # Set all known colors that weren't defined in this theme
-            # to empty, to avoid keeping around coloration from an earlier theme.
-            for what in KNOWN_COLORS - have_colors:
-                output += "\n" + self.do_set_color_for_variable(what, "")
-
         elif p == "/get_function/":
             what = postvars.get("what")
             output = [self.do_get_function(what[0])]