From 065f82f485112dfa1495207d713c524647178003 Mon Sep 17 00:00:00 2001
From: Florian Bruhin <git@the-compiler.org>
Date: Sat, 1 Jul 2017 22:08:50 +0200
Subject: [PATCH] Fix endless recursion while validating aliases

---
 qutebrowser/config/configtypes.py     | 28 ++++++++++++++++++++-------
 tests/unit/config/test_configtypes.py |  1 +
 2 files changed, 22 insertions(+), 7 deletions(-)

diff --git a/qutebrowser/config/configtypes.py b/qutebrowser/config/configtypes.py
index c59283fd6..a39da0979 100644
--- a/qutebrowser/config/configtypes.py
+++ b/qutebrowser/config/configtypes.py
@@ -726,18 +726,32 @@ class Command(BaseType):
 
     """Base class for a command value with arguments."""
 
+    # See to_py for details
+    unvalidated = False
+
     def to_py(self, value):
         self._basic_py_validation(value, str)
         if not value:
             return None
 
-        # FIXME:conf is it okay to import runners.py here?
-        from qutebrowser.commands import runners, cmdexc
-        parser = runners.CommandParser()
-        try:
-            list(parser.parse_all(value))
-        except cmdexc.Error as e:
-            raise configexc.ValidationError(value, str(e))
+        # This requires some trickery, as runners.CommandParser uses
+        # conf.val.aliases, which in turn map to a command again,
+        # leading to an endless recursion.
+        # To fix that, we turn off validating other commands (alias values)
+        # while validating a command.
+        # FIXME:conf Can't test this because we don't have a real config in
+        # TestCommand
+        if not Command.unvalidated:  # pragma: no branch
+            Command.unvalidated = True
+            try:
+                from qutebrowser.commands import runners, cmdexc
+                parser = runners.CommandParser()
+                try:
+                    list(parser.parse_all(value))
+                except cmdexc.Error as e:
+                    raise configexc.ValidationError(value, str(e))
+            finally:
+                Command.unvalidated = False
 
         return value
 
diff --git a/tests/unit/config/test_configtypes.py b/tests/unit/config/test_configtypes.py
index 2e4958095..dcb7733e2 100644
--- a/tests/unit/config/test_configtypes.py
+++ b/tests/unit/config/test_configtypes.py
@@ -1035,6 +1035,7 @@ class TestCommand:
             'cmd2': stubs.FakeCommand(desc="desc 2")})
         monkeypatch.setattr(configtypes, 'cmdutils', cmd_utils)
         # FIXME:conf use some kind of config_stub here
+        # also remove the no branch pragma from configtypes.Command then
         ns = types.SimpleNamespace()
         ns.aliases = {'alias': 'cmd1'}
         monkeypatch.setattr('qutebrowser.config.config.val', ns)