Fix Back being trapped on the connecting popup (all three connect flows)

BT Inspector, BLE HID Host and Sensor Dashboard showed a "Connecting..." /
"Discovering..." popup whose Back handler ignored the key, so if a connect or
service discovery ran long the user was stuck until it timed out. Back on that
popup now sets a cancel flag and returns to the scan list immediately; the
worker thread notices the flag when its current operation finishes, drops the
half-made connection and resumes scanning, and the completion handler ignores
the cancelled result instead of jumping into the device/readings view.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LEaD4ZeAfvWLBUxXp8G11r

ble_hid_host/ble_hid_host.c

@@ -84,6 +84,7 @@ typedef struct {
     Sub subs[SUBS_MAX];
     int sub_count;
     bool connected_ok;
+    volatile bool cancel;
     char setup_msg[48];
 } App;
 
@@ -95,6 +96,8 @@ typedef struct {
 
 // ---- logging ----------------------------------------------------------------
 
+static App* s_app; // popup Back callback (popup view ctx isn't the App)
+
 static void app_log(App* app, const char* fmt, ...) {
     if(!app->log) return;
     DateTime dt;
@@ -240,7 +243,13 @@ static int32_t worker_thread(void* ctx) {
     while(furi_message_queue_get(app->jobs, &job, FuriWaitForever) == FuriStatusOk) {
         if(job == JobQuit) break;
         if(job == JobConnect) {
-            app->connected_ok = bc_connect(app->bc, &app->dev, 8000) && hid_setup(app);
+            bool ok = bc_connect(app->bc, &app->dev, 8000) && hid_setup(app);
+            if(app->cancel) {
+                if(bc_is_connected(app->bc)) bc_disconnect(app->bc);
+                bc_scan_start(app->bc);
+                ok = false;
+            }
+            app->connected_ok = ok;
         } else if(job == JobDisconnect) {
             bc_disconnect(app->bc);
             bc_scan_start(app->bc);
@@ -442,9 +451,11 @@ static uint32_t nav_mon_back(void* ctx) {
     return ViewScan;
 }
 
-static uint32_t nav_stay_popup(void* ctx) {
+static uint32_t nav_connecting_back(void* ctx) {
     UNUSED(ctx);
-    return ViewPopup;
+    s_app->cancel = true;
+    s_app->cur_view = ViewScan;
+    return ViewScan;
 }
 
 // ---- events -----------------------------------------------------------------
@@ -508,12 +519,17 @@ static bool custom_event_cb(void* ctx, uint32_t event) {
             false);
         if(have) {
             app_log(app, "CONNECTING %s", dev_label(&app->dev));
+            app->cancel = false;
             show_popup(app, "Connecting...", dev_label(&app->dev), false);
             furi_message_queue_put(app->jobs, &(JobType){JobConnect}, 0);
         }
     } break;
     case EvtNotify: on_notify(app); break;
     case EvtJobDone:
+        if(app->cancel) {
+            app->cancel = false;
+            break;
+        }
         if(app->connected_ok) {
             char hdr[40];
             snprintf(hdr, sizeof(hdr), "%s", dev_label(&app->dev));
@@ -554,6 +570,7 @@ int32_t ble_hid_host_app(void* p) {
     UNUSED(p);
     App* app = malloc(sizeof(App));
     memset(app, 0, sizeof(App));
+    s_app = app;
     app->gui = furi_record_open(RECORD_GUI);
     app->storage = furi_record_open(RECORD_STORAGE);
     app->jobs = furi_message_queue_alloc(8, sizeof(JobType));
@@ -582,7 +599,7 @@ int32_t ble_hid_host_app(void* p) {
     view_dispatcher_add_view(app->vd, ViewMonitor, app->mon_view);
 
     app->popup = popup_alloc();
-    view_set_previous_callback(popup_get_view(app->popup), nav_stay_popup);
+    view_set_previous_callback(popup_get_view(app->popup), nav_connecting_back);
     view_dispatcher_add_view(app->vd, ViewPopup, popup_get_view(app->popup));
 
     app->timer = furi_timer_alloc(timer_cb, FuriTimerTypePeriodic, app);

ble_sensor/ble_sensor.c

@@ -70,9 +70,12 @@ typedef struct {
     BcService services[BC_MAX_SERVICES];
     BcChar chars[BC_MAX_CHARS];
     bool connected_ok;
+    volatile bool cancel;
     char setup_msg[40];
 } App;
 
+static App* s_app; // for the popup Back callback (popup view ctx isn't the App)
+
 static const char* dev_label(const BcDevice* d) {
     return d->name[0] ? d->name : "(no name)";
 }
@@ -139,9 +142,15 @@ static int32_t worker_thread(void* ctx) {
     JobType job;
     while(furi_message_queue_get(app->jobs, &job, FuriWaitForever) == FuriStatusOk) {
         if(job == JobQuit) break;
-        if(job == JobConnect)
+        if(job == JobConnect) {
-            app->connected_ok = bc_connect(app->bc, &app->dev, 8000) && sensor_setup(app);
+            bool ok = bc_connect(app->bc, &app->dev, 8000) && sensor_setup(app);
-        else if(job == JobDisconnect) {
+            if(app->cancel) { // user pressed Back while we were busy
+                if(bc_is_connected(app->bc)) bc_disconnect(app->bc);
+                bc_scan_start(app->bc);
+                ok = false;
+            }
+            app->connected_ok = ok;
+        } else if(job == JobDisconnect) {
             bc_disconnect(app->bc);
             bc_scan_start(app->bc);
         }
@@ -288,9 +297,11 @@ static uint32_t scan_exit(void* ctx) {
     UNUSED(ctx);
     return VIEW_NONE;
 }
-static uint32_t stay_popup(void* ctx) {
+static uint32_t connecting_back(void* ctx) {
     UNUSED(ctx);
-    return ViewPopup;
+    s_app->cancel = true; // worker will drop the half-made connection
+    s_app->cur = ViewScan;
+    return ViewScan;
 }
 
 static void popup_cb(void* ctx) {
@@ -343,6 +354,7 @@ static bool custom_cb(void* ctx, uint32_t event) {
             popup_set_context(app->popup, app);
             popup_set_header(app->popup, "Connecting...", 64, 26, AlignCenter, AlignCenter);
             popup_set_text(app->popup, dev_label(&app->dev), 64, 40, AlignCenter, AlignCenter);
+            app->cancel = false;
             app->cur = ViewPopup;
             view_dispatcher_switch_to_view(app->vd, ViewPopup);
             furi_message_queue_put(app->jobs, &(JobType){JobConnect}, 0);
@@ -350,6 +362,10 @@ static bool custom_cb(void* ctx, uint32_t event) {
     } break;
     case EvtNotify: on_notify(app); break;
     case EvtJobDone:
+        if(app->cancel) { // user already backed out to the scan list
+            app->cancel = false;
+            break;
+        }
         if(app->connected_ok) {
             with_view_model(
                 app->readings_view, ReadingsModel * m,
@@ -383,6 +399,7 @@ int32_t ble_sensor_app(void* p) {
     UNUSED(p);
     App* app = malloc(sizeof(App));
     memset(app, 0, sizeof(App));
+    s_app = app;
     app->gui = furi_record_open(RECORD_GUI);
     app->jobs = furi_message_queue_alloc(8, sizeof(JobType));
     app->notify_q = furi_message_queue_alloc(16, sizeof(NotifyMsg));
@@ -410,7 +427,7 @@ int32_t ble_sensor_app(void* p) {
     view_dispatcher_add_view(app->vd, ViewReadings, app->readings_view);
 
     app->popup = popup_alloc();
-    view_set_previous_callback(popup_get_view(app->popup), stay_popup);
+    view_set_previous_callback(popup_get_view(app->popup), connecting_back);
     view_dispatcher_add_view(app->vd, ViewPopup, popup_get_view(app->popup));
 
     app->timer = furi_timer_alloc(timer_cb, FuriTimerTypePeriodic, app);

bt_inspector/bt_inspector.c

@@ -129,6 +129,7 @@ typedef struct {
 
     JobType job;
     bool job_ok;
+    volatile bool cancel;
     FuriString* status;
     FuriString* info_text;
 } App;
@@ -853,7 +854,10 @@ static uint32_t nav_exit(void* ctx) {
 
 static uint32_t nav_stay_popup(void* ctx) {
     UNUSED(ctx);
-    return ViewPopup;
+    // Back on a connect/discover popup: abort and return to the scan list.
+    nav_app->cancel = true;
+    nav_app->cur_view = ViewScan;
+    return ViewScan;
 }
 
 static uint32_t nav_page_back(void* ctx) {
@@ -916,6 +920,16 @@ static void on_tick(App* app) {
 }
 
 static void on_job_done(App* app) {
+    if(app->cancel) { // user backed out of the connect/discover popup
+        app->cancel = false;
+        if(app->job != JobDisconnect) {
+            if(bc_is_connected(app->bc))
+                post_job(app, JobDisconnect);
+            else
+                bc_scan_start(app->bc);
+        }
+        return;
+    }
     switch(app->job) {
     case JobConnect:
         if(app->job_ok) {
@@ -1038,6 +1052,7 @@ static bool custom_event_cb(void* ctx, uint32_t event) {
     case EvtPageCenter:
         if(app->page_kind == PageDetails) {
             app_log(app, "CONNECTING %s", dev_label(&app->dev));
+            app->cancel = false;
             show_popup(app, "Connecting...", dev_label(&app->dev), false);
             post_job(app, JobConnect);
         } else if(app->page_kind == PageChar) {
@@ -1059,6 +1074,12 @@ static bool custom_event_cb(void* ctx, uint32_t event) {
     case EvtJobDone: on_job_done(app); break;
     case EvtNotify: on_notify(app); break;
     case EvtPopupDone:
+        if(app->cancel) {
+            app->cancel = false;
+            bc_scan_start(app->bc);
+            show_view(app, ViewScan);
+            break;
+        }
         if(app->after_popup == AfterPopupServices) {
             show_view(app, ViewServices);
         } else {