Make cursor keys go through completion if a text was entered

This hopefully helps with people who try to use arrow keys for the completion,
while still making the command history somewhat discoverable.

doc/changelog.asciidoc

@@ -74,6 +74,10 @@ Changed
   download.
 - Much improved user stylesheet handling which reduces flickering
   and updates immediately after setting a stylesheet.
+- `:completion-item-focus` now has a `--history` flag which causes it to go
+  through the command history when no text was entered. The default bindings for
+  cursor keys in the completion changed to use that, so that they can be used
+  again to navigate through completion items when a text was entered.
 
 Fixed
 ~~~~~

doc/help/commands.asciidoc

@@ -1428,13 +1428,16 @@ Delete the current completion item.
 
 [[completion-item-focus]]
 === completion-item-focus
-Syntax: +:completion-item-focus 'which'+
+Syntax: +:completion-item-focus [*--history*] 'which'+
 
 Shift the focus of the completion menu to another item.
 
 ==== positional arguments
 * +'which'+: 'next', 'prev', 'next-category', or 'prev-category'.
 
+==== optional arguments
+* +*-H*+, +*--history*+: Navigate through command history if no text was typed.
+
 [[completion-item-yank]]
 === completion-item-yank
 Syntax: +:completion-item-yank [*--sel*]+

doc/help/configuring.asciidoc

@@ -17,15 +17,24 @@ did in your old configuration, compared to the old defaults.
 
 Other changes in default settings:
 
-- `<Up>` and `<Down>` in the completion now navigate through command history
-  instead of selecting completion items. Use `<Tab>`/`<Shift-Tab>` to cycle
-  through the completion instead.
+- In v1.1.x and newer, `<Up>` and `<Down>` navigate through command history
+  if no text was entered yet.
+  With v1.0.x, they always navigate through command history instead of selecting
+  completion items. Use `<Tab>`/`<Shift-Tab>` to cycle through the completion
+  instead.
   You can get back the old behavior by doing:
 +
 ----
 :bind -m command <Up> completion-item-focus prev
 :bind -m command <Down> completion-item-focus next
 ----
++
+or always navigate through command history with
++
+----
+:bind -m command <Up> command-history-prev
+:bind -m command <Down> command-history-next
+----
 
 - The default for `completion.web_history_max_items` is now set to `-1`, showing
   an unlimited number of items in the completion for `:open` as the new

doc/help/settings.asciidoc

@@ -430,13 +430,13 @@ Default:
 * +pass:[<Ctrl-U>]+: +pass:[rl-unix-line-discard]+
 * +pass:[<Ctrl-W>]+: +pass:[rl-unix-word-rubout]+
 * +pass:[<Ctrl-Y>]+: +pass:[rl-yank]+
-* +pass:[<Down>]+: +pass:[command-history-next]+
+* +pass:[<Down>]+: +pass:[completion-item-focus --history next]+
 * +pass:[<Escape>]+: +pass:[leave-mode]+
 * +pass:[<Return>]+: +pass:[command-accept]+
 * +pass:[<Shift-Delete>]+: +pass:[completion-item-del]+
 * +pass:[<Shift-Tab>]+: +pass:[completion-item-focus prev]+
 * +pass:[<Tab>]+: +pass:[completion-item-focus next]+
-* +pass:[<Up>]+: +pass:[command-history-prev]+
+* +pass:[<Up>]+: +pass:[completion-item-focus --history priv]+
 - +pass:[hint]+:
 
 * +pass:[<Ctrl-B>]+: +pass:[hint all tab-bg]+

qutebrowser/completion/completionwidget.py

@@ -226,14 +226,31 @@ class CompletionView(QTreeView):
                        modes=[usertypes.KeyMode.command], scope='window')
     @cmdutils.argument('which', choices=['next', 'prev', 'next-category',
                                          'prev-category'])
-    def completion_item_focus(self, which):
+    @cmdutils.argument('history', flag='H')
+    def completion_item_focus(self, which, history=False):
         """Shift the focus of the completion menu to another item.
 
         Args:
             which: 'next', 'prev', 'next-category', or 'prev-category'.
+            history: Navigate through command history if no text was typed.
         """
         if not self._active:
             return
+
+        if history:
+            status = objreg.get('status-command', scope='window',
+                                window=self._win_id)
+            if status.text() == ':' or status.history.is_browsing():
+                if which == 'next':
+                    status.command_history_next()
+                    return
+                elif which == 'prev':
+                    status.command_history_prev()
+                    return
+                else:
+                    raise cmdexc.CommandError("Can't combine --history with "
+                                              "{}!".format(which))
+
         selmodel = self.selectionModel()
 
         if which == 'next':

qutebrowser/config/configdata.yml

@@ -2269,8 +2269,8 @@ bindings.default:
     command:
       <Ctrl-P>: command-history-prev
       <Ctrl-N>: command-history-next
-      <Up>: command-history-prev
-      <Down>: command-history-next
+      <Up>: completion-item-focus --history prev
+      <Down>: completion-item-focus --history next
       <Shift-Tab>: completion-item-focus prev
       <Tab>: completion-item-focus next
       <Ctrl-Tab>: completion-item-focus next-category

tests/end2end/features/misc.feature

@@ -469,6 +469,15 @@ Feature: Various utility commands.
         And I run :command-accept
         Then the message "blah" should be shown
 
+    Scenario: Calling previous command with :completion-item-focus
+        When I run :set-cmd-text :message-info blah
+        And I run :command-accept
+        And I wait for "blah" in the log
+        And I run :set-cmd-text :
+        And I run :completion-item-focus prev --history
+        And I run :command-accept
+        Then the message "blah" should be shown
+
     Scenario: Browsing through commands 
         When I run :set-cmd-text :message-info blarg
         And I run :command-accept