|author||Boris Kolpackov <email@example.com>||2018-05-25 09:14:48 +0200|
|committer||Boris Kolpackov <firstname.lastname@example.org>||2018-05-25 09:14:48 +0200|
Fix postponed group/member state race
2 files changed, 20 insertions, 6 deletions
diff --git a/build2/algorithm.cxx b/build2/algorithm.cxx
index 8ee6d47..6743907 100644
@@ -1790,15 +1790,29 @@ namespace build2
const target& g (*t.group);
- if (execute (a, g) == target_state::busy)
+ target_state gs (execute (a, g));
+ if (gs == target_state::busy)
sched.wait (target::count_executed (),
- // Indicate to execute() that this target's state comes from the group
- // (which, BTW, can be failed).
+ // Return target_state::group to signal to execute() that this target's
+ // state comes from the group (which, BTW, can be failed).
+ // There is just one small problem: if the returned group state is
+ // postponed, then this means the group hasn't been executed yet. And if
+ // we return target_state::group, then this means any state queries (see
+ // executed_state()) will be directed to the target which might still not
+ // be executed or, worse, is being executed as we query.
+ // So in this case we return target_state::postponed (which will result in
+ // the member being treated as unchanged). This is how it is done for
+ // prerequisites and seeing that we've been acting as if the group is our
+ // prerequisite, there is no reason to deviate (see the recipe return
+ // value documentation for details).
- return target_state::group;
+ return gs != target_state::postponed ? target_state::group : gs;
diff --git a/build2/target.ixx b/build2/target.ixx
index ea91b6e..88bc530 100644
@@ -94,14 +94,14 @@ namespace build2
// We go an extra step and short-circuit to the target state even if the
// raw state is not group provided the recipe is group_recipe and the
- // state is not failed.
+ // state is unknown (see mtime() for some ideas on why we do it).
const opstate& s (state[a]);
if (s.state == target_state::group)
- if (s.state != target_state::failed && group != nullptr)
+ if (s.state == target_state::unknown && group != nullptr)
if (recipe_function* const* f = s.recipe.target<recipe_function*> ())
return *f == &group_action;