[fix][backend] restore FailRetry logic to skip completed evaluators

[Lysssyo]

What type of PR is this?

fix: A bug fix

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1. Defect 1: Historical Result ID Mapping Error

1.1 Problem Description

In the GetExptItemTurnResults method, when constructing the mapping table for historical results, the EvaluatorVersionID (Evaluator Version ID) was incorrectly assigned as the Value. The expected Value should have been the EvaluatorResultID (Primary Key ID of the evaluation record).

1.2 Fix Details

• File: backend/modules/evaluation/domain/service/expt_result_impl.go
• Method: GetExptItemTurnResults

Code Comparison:

// Before (Bug)
// Error: Value assigned as VersionID (e.g., 1001)
turnEvaluatorVerIDToResultID[ref.ExptTurnResultID][ref.EvaluatorVersionID] = ref.EvaluatorVersionID

// After (Fix)
// Correct: Value assigned as ResultID (e.g., 74839201)
turnEvaluatorVerIDToResultID[ref.ExptTurnResultID][ref.EvaluatorVersionID] = ref.EvaluatorResultID

1.3 Verification and Impact

• Table: expt_turn_result_run_log
• Column: evaluator_result_ids
• Before Fix: {"EvalVerIDToResID":{"1001":1001}} — Invalid reference pointing to a non-existent record ID.
• After Fix: {"EvalVerIDToResID":{"1001":74839201}} — Valid reference correctly pointing to the primary key in the evaluator_record table.

Note: Although the database would eventually "self-heal" by overwriting old data with new data generated from re-running the LLM evaluation if this issue were left unfixed, the primary purpose of the PreEval stage is to reuse old data. If the ID is incorrect here, the Worker cannot retrieve the corresponding historical record using the incorrect ID when initializing the context via e.evaluatorRecordService.BatchGetEvaluatorRecord. Consequently, the checkpoint recovery mechanism would fail at the very first step.

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2. Defect 2: Worker Cache Key Mismatch

2.1 Problem Description

Even if the ID mapping is correct, the Worker used RecordID as the Map Key when constructing the context cache. However, the subsequent read logic used EvaluatorVersionID as the Key for lookups. This Key Mismatch resulted in a permanent cache miss.

2.2 Fix Details

• File: backend/modules/evaluation/domain/service/expt_run_item_impl.go
• Method: buildExptTurnEvalCtx

Code Comparison:

// Before (Bug)
// Error: Using RecordID as Key
recordMap[record.ID] = record 

// After (Fix)
// Correct: Using EvaluatorVersionID as Key, aligning with the read logic
recordMap[record.EvaluatorVersionID] = record

2.3 Verification (Memory Level)

After the fix, the Worker execution flow is as follows:

1. Context Construction (buildExptTurnEvalCtx):
   Correctly constructs the etec.ExptTurnRunResult.EvaluatorResults Map with EvaluatorVersionID as the Key.

2. Execution (CallEvaluators):
   When iterating through evaluators, the cache is successfully hit, allowing completed tasks to be skipped.

   // backend/modules/evaluation/domain/service/expt_run_item_turn_impl.go
   
   func (e *DefaultExptTurnEvaluationImpl) CallEvaluators(ctx context.Context, etec *entity.ExptTurnEvalCtx, targetResult *entity.EvalTargetRecord) (map[int64]*entity.EvaluatorRecord, error) {  
       // ...
       for _, evaluatorVersion := range expt.Evaluators {  
           // Verification Point: Lookup using VersionID now successfully retrieves the cache
           existResult := etec.ExptTurnRunResult.GetEvaluatorRecord(evaluatorVersion.GetEvaluatorVersionID())  
     
           if existResult != nil && existResult.Status == entity.EvaluatorRunStatusSuccess {  
               // Successfully skipped!
               evaluatorResults[existResult.ID] = existResult
               continue  
           }  
           // ...
       }
       // ...
   }

(Optional) Which issue(s) this PR fixes

Fixes #400

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

@@            Coverage Diff             @@
##             main     #402      +/-   ##
==========================================
- Coverage   70.00%   70.00%   -0.01%     
==========================================
  Files         619      619              
  Lines       58718    58718              
==========================================
- Hits        41106    41104       -2     
- Misses      14627    14628       +1     
- Partials     2985     2986       +1     

Flag	Coverage Δ
unittests	70.00% <100.00%> (-0.01%)	⬇️

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Files with missing lines	Coverage Δ
...ules/evaluation/domain/service/expt_result_impl.go	64.86% <100.00%> (ø)
...es/evaluation/domain/service/expt_run_item_impl.go	67.92% <100.00%> (ø)

... and 2 files with indirect coverage changes

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[lsy357]

Change merged, and this patch will ship with next version. Thanks for making loop better!