Fix grade average: allow large grade matrices and decouple bonus from the final grade

src/app/[locale]/(app)/studies/actions.ts

@@ -24,7 +24,9 @@ const gradeScaleSchema = z
       grade: z.number().min(1).max(6),
     })
   )
-  .max(30)
+  // A percent→grade table can be fine-grained (e.g. one row per percentage
+  // point), so allow a generous number of rows.
+  .max(200)
 
 const programSchema = z.object({
   name: z.string().min(1).max(200),

src/components/learn/module-assessment-card.tsx

@@ -184,8 +184,6 @@ export function ModuleAssessmentCard({
           {!passFail && final.percent != null && (
             <p className="text-muted-foreground text-xs tabular-nums">
               {Math.round(final.percent)} %
-              {final.bonus && final.bonus.percentPoints > 0 &&
-                ` · ${t("bonusApplied", { points: final.bonus.percentPoints })}`}
             </p>
           )}
         </div>

src/lib/grades.test.ts

@@ -152,7 +152,7 @@ describe("effectiveBonus", () => {
 })
 
 describe("moduleFinalGrade", () => {
-  it("applies a percent-point bonus before mapping to a grade", () => {
+  it("derives the grade from the percentage only — a percent-point bonus does not raise it", () => {
     const r = moduleFinalGrade({
       module: {
         passFail: false,
@@ -165,13 +165,14 @@ describe("moduleFinalGrade", () => {
       assignments: [{ kind: "graded", status: "graded", percent: 100 }],
       scale: null,
     })
-    // 78 + 5 = 83 → 2.0 on the default scale (≥80)
-    expect(r.percent).toBe(83)
-    expect(r.grade).toBe(2.0)
+    // 78 % → 2.3 (≥75); the +5 bonus is reported but not applied to the grade.
+    expect(r.percent).toBe(78)
+    expect(r.grade).toBe(2.3)
     expect(r.source).toBe("assessment")
+    expect(r.bonus?.percentPoints).toBe(5)
   })
 
-  it("applies grade steps and clamps at 1.0", () => {
+  it("does not apply grade steps to the final grade", () => {
     const r = moduleFinalGrade({
       module: {
         passFail: false,
@@ -180,12 +181,31 @@ describe("moduleFinalGrade", () => {
         bonusMinAvgPercent: null,
         bonusMinCompletedShare: null,
       },
-      attempts: [{ attempt: 1, resultPercent: "96", passed: true }],
+      attempts: [{ attempt: 1, resultPercent: "82", passed: true }],
+      assignments: [{ kind: "graded", status: "graded", percent: 100 }],
+      scale: null,
+    })
+    // 82 % → 2.0; without decoupling the 0.3 step would have yielded 1.7.
+    expect(r.grade).toBe(2.0)
+    expect(r.bonus?.gradeSteps).toBe(0.3)
+  })
+
+  it("yields the same final grade with or without a configured bonus", () => {
+    const attempts = [{ attempt: 1, resultPercent: "78", passed: true }]
+    const withBonus = moduleFinalGrade({
+      module: {
+        passFail: false,
+        bonusType: "percent_points",
+        bonusValue: "5",
+        bonusMinAvgPercent: null,
+        bonusMinCompletedShare: null,
+      },
+      attempts,
       assignments: [{ kind: "graded", status: "graded", percent: 100 }],
       scale: null,
     })
-    // 96 → 1.0, minus 0.3 step clamps back to 1.0
-    expect(r.grade).toBe(1.0)
+    const withoutBonus = moduleFinalGrade({ module: noBonus, attempts, assignments: [], scale: null })
+    expect(withBonus.grade).toBe(withoutBonus.grade)
   })
 
   it("uses the latest attempt", () => {

src/lib/grades.ts

@@ -174,9 +174,10 @@ export type FinalGrade = {
 }
 
 /**
- * Computes a module's final grade from its latest assessment attempt plus the
- * assignment bonus, falling back to legacy free-form grades when no attempt
- * exists. Pass/fail modules yield only a passed flag.
+ * Computes a module's final grade from its latest assessment attempt (achieved
+ * percentage → grade scale), falling back to legacy free-form grades when no
+ * attempt exists. The assignment bonus is computed and returned for display but
+ * does not alter the final grade. Pass/fail modules yield only a passed flag.
  */
 export function moduleFinalGrade(input: FinalGradeInput): FinalGrade {
   const { module, attempts, assignments, scale, legacyGrades } = input
@@ -198,12 +199,13 @@ export function moduleFinalGrade(input: FinalGradeInput): FinalGrade {
 
     const basePercent = num(latest.resultPercent)
     if (basePercent != null) {
-      const boostedPercent = Math.min(100, basePercent + bonus.percentPoints)
-      let grade = percentToGrade(scale, boostedPercent)
-      grade = Math.max(BEST_GRADE, grade - bonus.gradeSteps)
+      // The final grade is derived purely from the achieved percentage via the
+      // grade scale. A configured assignment bonus is reported for information
+      // only (see `bonus` below) and never shifts the final grade.
+      const grade = percentToGrade(scale, basePercent)
       return {
         grade,
-        percent: boostedPercent,
+        percent: basePercent,
         passed: grade <= PASS_THRESHOLD,
         attempt: latest.attempt,
         source: "assessment",