5 files changed, 68 insertions, 10 deletions

diff --git a/src/mbgl/map/map.cpp b/src/mbgl/map/map.cpp
index a7beb0f1e2..d81544eed5 100644
--- a/src/mbgl/map/map.cpp
+++ b/src/mbgl/map/map.cpp
@@ -747,6 +747,11 @@ void Map::Impl::onInvalidate() {
 }
 
 void Map::Impl::onUpdate() {
+    // Don't load/render anything in still mode until explicitly requested.
+    if (mode != MapMode::Continuous && !stillImageRequest) {
+        return;
+    }
+    
     TimePoint timePoint = mode == MapMode::Continuous ? Clock::now() : Clock::time_point::max();
 
     transform.updateTransitions(timePoint);
diff --git a/src/mbgl/map/transform.cpp b/src/mbgl/map/transform.cpp
index 105adf0400..da8e243d91 100644
--- a/src/mbgl/map/transform.cpp
+++ b/src/mbgl/map/transform.cpp
@@ -594,13 +594,10 @@ void Transform::startTransition(const CameraOptions& camera,
                 animation.transitionFrameFn(t);
             }
             observer.onCameraIsChanging();
+            return false;
         } else {
-            transitionFinishFn();
-            transitionFinishFn = nullptr;
-
-            // This callback gets destroyed here,
-            // we can only return after this point.
-            transitionFrameFn = nullptr;
+            // Indicate that we need to terminate this transition
+            return true;
         }
     };
 
@@ -615,7 +612,14 @@ void Transform::startTransition(const CameraOptions& camera,
     };
 
     if (!isAnimated) {
-        transitionFrameFn(Clock::now());
+        auto update = std::move(transitionFrameFn);
+        auto finish = std::move(transitionFinishFn);
+
+        transitionFrameFn = nullptr;
+        transitionFinishFn = nullptr;
+
+        update(Clock::now());
+        finish();
     }
 }
 
@@ -624,8 +628,43 @@ bool Transform::inTransition() const {
 }
 
 void Transform::updateTransitions(const TimePoint& now) {
-    if (transitionFrameFn) {
-        transitionFrameFn(now);
+
+    // Use a temporary function to ensure that the transitionFrameFn lambda is
+    // called only once per update.
+
+    // This addresses the symptoms of https://github.com/mapbox/mapbox-gl-native/issues/11180
+    // where setting a shape source to nil (or similar) in the `onCameraIsChanging`
+    // observer function causes `Map::Impl::onUpdate()` to be called which
+    // in turn calls this function (before the current iteration has completed),
+    // leading to an infinite loop. See https://github.com/mapbox/mapbox-gl-native/issues/5833
+    // for a similar, related, issue.
+    //
+    // By temporarily nulling the `transitionFrameFn` (and then restoring it
+    // after the temporary has been called) we stop this recursion.
+    //
+    // It's important to note that the scope of this change is stop the above
+    // crashes. It doesn't address any potential deeper issue (for example
+    // user error, how often and when transition callbacks are called).
+
+    auto transition = std::move(transitionFrameFn);
+    transitionFrameFn = nullptr;
+
+    if (transition && transition(now)) {
+        // If the transition indicates that it is complete, then we should call
+        // the finish lambda (going via a temporary as above)
+        auto finish = std::move(transitionFinishFn);
+
+        transitionFinishFn = nullptr;
+        transitionFrameFn = nullptr;
+
+        if (finish) {
+            finish();
+        }
+    } else if (!transitionFrameFn) {
+        // We have to check `transitionFrameFn` is nil here, since a new transition
+        // may have been triggered in a user callback (from the transition call
+        // above)
+        transitionFrameFn = std::move(transition);
     }
 }
 
diff --git a/src/mbgl/map/transform.hpp b/src/mbgl/map/transform.hpp
index d429c57661..bff44a2dcd 100644
--- a/src/mbgl/map/transform.hpp
+++ b/src/mbgl/map/transform.hpp
@@ -165,7 +165,7 @@ private:
 
     TimePoint transitionStart;
     Duration transitionDuration;
-    std::function<void(const TimePoint)> transitionFrameFn;
+    std::function<bool(const TimePoint)> transitionFrameFn;
     std::function<void()> transitionFinishFn;
 };
 
diff --git a/src/mbgl/map/transform_state.cpp b/src/mbgl/map/transform_state.cpp
index 18d2c24aee..a85b251fb4 100644
--- a/src/mbgl/map/transform_state.cpp
+++ b/src/mbgl/map/transform_state.cpp
@@ -421,4 +421,17 @@ float TransformState::getCameraToTileDistance(const UnwrappedTileID& tileID) con
     return projectedCenter[3];
 }
 
+float TransformState::maxPitchScaleFactor() const {
+    if (size.isEmpty()) {
+        return {};
+    }
+    auto latLng = screenCoordinateToLatLng({ 0, static_cast<float>(getSize().height) });
+    mat4 mat = coordinatePointMatrix(getZoom());
+    Point<double> pt = Projection::project(latLng, scale) / double(util::tileSize);
+    vec4 p = {{ pt.x, pt.y, 0, 1 }};
+    vec4 topPoint;
+    matrix::transformMat4(topPoint, p, mat);
+    return topPoint[3] / getCameraToCenterDistance();
+}
+
 } // namespace mbgl
diff --git a/src/mbgl/map/transform_state.hpp b/src/mbgl/map/transform_state.hpp
index 451802034d..b6f8ae4424 100644
--- a/src/mbgl/map/transform_state.hpp
+++ b/src/mbgl/map/transform_state.hpp
@@ -87,6 +87,7 @@ public:
     }
 
     float getCameraToTileDistance(const UnwrappedTileID&) const;
+    float maxPitchScaleFactor() const;
 
 private:
     bool rotatedNorth() const;