Fix/disable FSRS short-term scheduler if w[17] or w[18] is zero (#3788)

* Fix/disable FSRS short-term scheduler if w[17] or w[18] is zero

* fix bracket

* rename variable

rslib/src/scheduler/answering/mod.rs

@@ -74,6 +74,7 @@ struct CardStateUpdater {
     /// Set if FSRS is enabled.
     desired_retention: Option<f32>,
     fsrs_short_term_with_steps: bool,
+    fsrs_allow_short_term: bool,
 }
 
 impl CardStateUpdater {
@@ -112,6 +113,7 @@ impl CardStateUpdater {
             },
             fsrs_next_states: self.fsrs_next_states.clone(),
             fsrs_short_term_with_steps_enabled: self.fsrs_short_term_with_steps,
+            fsrs_allow_short_term: self.fsrs_allow_short_term,
         }
     }
 
@@ -462,6 +464,16 @@ impl Collection {
         let desired_retention = fsrs_enabled.then_some(config.inner.desired_retention);
         let fsrs_short_term_with_steps =
             self.get_config_bool(BoolKey::FsrsShortTermWithStepsEnabled);
+        let fsrs_allow_short_term = if fsrs_enabled {
+            let params = config.fsrs_params();
+            if params.len() == 19 {
+                params[17] > 0.0 && params[18] > 0.0
+            } else {
+                false
+            }
+        } else {
+            false
+        };
         Ok(CardStateUpdater {
             fuzz_seed: get_fuzz_seed(&card, false),
             card,
@@ -472,6 +484,7 @@ impl Collection {
             fsrs_next_states,
             desired_retention,
             fsrs_short_term_with_steps,
+            fsrs_allow_short_term,
         })
     }
 

rslib/src/scheduler/states/learning.rs

@@ -51,7 +51,8 @@ impl LearnState {
             let (interval, short_term) = if let Some(states) = &ctx.fsrs_next_states {
                 (
                     states.again.interval,
-                    (ctx.fsrs_short_term_with_steps_enabled || ctx.steps.is_empty())
+                    ctx.fsrs_allow_short_term
+                        && (ctx.fsrs_short_term_with_steps_enabled || ctx.steps.is_empty())
                         && states.again.interval < 0.5,
                 )
             } else {
@@ -97,7 +98,8 @@ impl LearnState {
             let (interval, short_term) = if let Some(states) = &ctx.fsrs_next_states {
                 (
                     states.hard.interval,
-                    (ctx.fsrs_short_term_with_steps_enabled || ctx.steps.is_empty())
+                    ctx.fsrs_allow_short_term
+                        && (ctx.fsrs_short_term_with_steps_enabled || ctx.steps.is_empty())
                         && states.hard.interval < 0.5,
                 )
             } else {
@@ -143,7 +145,8 @@ impl LearnState {
             let (interval, short_term) = if let Some(states) = &ctx.fsrs_next_states {
                 (
                     states.good.interval,
-                    (ctx.fsrs_short_term_with_steps_enabled || ctx.steps.is_empty())
+                    ctx.fsrs_allow_short_term
+                        && (ctx.fsrs_short_term_with_steps_enabled || ctx.steps.is_empty())
                         && states.good.interval < 0.5,
                 )
             } else {

rslib/src/scheduler/states/mod.rs

@@ -89,7 +89,7 @@ pub(crate) struct StateContext<'a> {
     pub fuzz_factor: Option<f32>,
     pub fsrs_next_states: Option<NextStates>,
     pub fsrs_short_term_with_steps_enabled: bool,
-
+    pub fsrs_allow_short_term: bool,
     // learning
     pub steps: LearningSteps<'a>,
     pub graduating_interval_good: u32,
@@ -149,6 +149,7 @@ impl StateContext<'_> {
             },
             fsrs_next_states: None,
             fsrs_short_term_with_steps_enabled: false,
+            fsrs_allow_short_term: false,
         }
     }
 }

rslib/src/scheduler/states/relearning.rs

@@ -69,7 +69,8 @@ impl RelearnState {
                 },
                 review: again_review,
             };
-            if (ctx.fsrs_short_term_with_steps_enabled || ctx.relearn_steps.is_empty())
+            if ctx.fsrs_allow_short_term
+                && (ctx.fsrs_short_term_with_steps_enabled || ctx.relearn_steps.is_empty())
                 && interval < 0.5
             {
                 again_relearn.into()
@@ -116,7 +117,8 @@ impl RelearnState {
                 },
                 review: hard_review,
             };
-            if (ctx.fsrs_short_term_with_steps_enabled || ctx.relearn_steps.is_empty())
+            if ctx.fsrs_allow_short_term
+                && (ctx.fsrs_short_term_with_steps_enabled || ctx.relearn_steps.is_empty())
                 && interval < 0.5
             {
                 hard_relearn.into()
@@ -169,7 +171,8 @@ impl RelearnState {
                 },
                 review: good_review,
             };
-            if (ctx.fsrs_short_term_with_steps_enabled || ctx.relearn_steps.is_empty())
+            if ctx.fsrs_allow_short_term
+                && (ctx.fsrs_short_term_with_steps_enabled || ctx.relearn_steps.is_empty())
                 && interval < 0.5
             {
                 good_relearn.into()

rslib/src/scheduler/states/review.rs

@@ -124,7 +124,8 @@ impl ReviewState {
                 review: again_review,
             }
             .into()
-        } else if (ctx.fsrs_short_term_with_steps_enabled || ctx.relearn_steps.is_empty())
+        } else if ctx.fsrs_allow_short_term
+            && (ctx.fsrs_short_term_with_steps_enabled || ctx.relearn_steps.is_empty())
             && scheduled_days < 0.5
         {
             again_relearn.into()