Use tries instead of depth for --backtrack.

Also, ensure that we fall back to legacy non-backtracking behavior if
backtracking fails for some reason. This is intended to solve
regressions reported in forum thread #847890.

diff --git a/pym/_emerge/depgraph.py b/pym/_emerge/depgraph.py
index a9c75be6d2f56c9b021b8b9e9e83bb0ce4f801a1..edc920d465f0546c864ad90b185a5c4d377ba7b3 100644 (file)
--- a/pym/_emerge/depgraph.py
+++ b/pym/_emerge/depgraph.py
@@ -5511,14 +5511,18 @@ def backtrack_depgraph(settings, trees, myopts, myparams,
 
 def _backtrack_depgraph(settings, trees, myopts, myparams, myaction, myfiles, spinner):
 
+       max_retries = myopts.get('--backtrack', 5)
        max_depth = myopts.get('--backtrack', 5)
-       allow_backtracking = max_depth > 0
+       allow_backtracking = max_retries > 0
        backtracker = Backtracker(max_depth)
+       backtracked = False
+       tries = 0
 
        frozen_config = _frozen_depgraph_config(settings, trees,
                myopts, spinner)
 
        while backtracker:
+               tries += 1
                backtrack_parameters = backtracker.get()
 
                mydepgraph = depgraph(settings, trees, myopts, myparams, spinner,
@@ -5529,21 +5533,22 @@ def _backtrack_depgraph(settings, trees, myopts, myparams, myaction, myfiles, sp
 
                if success or mydepgraph.success_without_autounmask():
                        break
+               elif tries > max_retries:
+                       break
                elif mydepgraph.need_restart():
-                       backtracker.feedback(mydepgraph.get_backtrack_infos())
+                       backtracked = True
+                       backtracker.feedback(mydepgraph.get_backtrack_infos())  
 
-       if not (success or mydepgraph.success_without_autounmask()) and backtracker.backtracked(): 
-               backtrack_parameters = backtracker.get_best_run()
+       if not (success or mydepgraph.success_without_autounmask()) and backtracked:
 
                if "--debug" in myopts:
                        writemsg_level(
                                "\n\nbacktracking aborted after %s tries\n\n" % \
-                               max_depth, noiselevel=-1, level=logging.DEBUG)
+                               tries, noiselevel=-1, level=logging.DEBUG)
 
                mydepgraph = depgraph(settings, trees, myopts, myparams, spinner,
                        frozen_config=frozen_config,
-                       allow_backtracking=False,
-                       backtrack_parameters=backtrack_parameters)
+                       allow_backtracking=False)
                success, favorites = mydepgraph.select_files(myfiles)
 
        return (success, mydepgraph, favorites)