fix: address Final Verification Wave findings

- Sync() now flushes BlockWriter before fd.Sync() for durability
- Pre-validate encoding before sequence allocation (design doc compliance)
- Remove dead _ = rec assignment in recover.go
- Remove unused maxPayload field from SegmentWriter
- Handle Put error in MemTable.Publish with panic on invariant violation

.omo/boulder.json

@@ -8,7 +8,7 @@
       "plan_name": "phase1-wal",
       "status": "active",
       "started_at": "2026-06-12T05:09:32.588Z",
-      "updated_at": "2026-06-12T06:20:06.478Z",
+      "updated_at": "2026-06-12T06:29:05.569Z",
       "session_ids": [
         "opencode:ses_145c3bae9ffeTB2zbsTym0Cev8"
       ],
@@ -146,6 +146,47 @@
           "status": "completed",
           "ended_at": "2026-06-12T06:20:06.478Z",
           "elapsed_ms": 85727
+        },
+        "final-wave:f1": {
+          "task_key": "final-wave:f1",
+          "task_label": "F1",
+          "task_title": "**Plan Compliance Audit** — `oracle`",
+          "session_id": "opencode:ses_1457cb69affe9rYiUhKWDB2kDd",
+          "agent": "Sisyphus-Junior",
+          "category": "unspecified-high",
+          "started_at": "2026-06-12T06:23:49.269Z",
+          "status": "running",
+          "updated_at": "2026-06-12T06:29:05.572Z"
+        },
+        "final-wave:f3": {
+          "task_key": "final-wave:f3",
+          "task_label": "F3",
+          "task_title": "Real Manual QA — execute all QA scenarios from the plan and verify cross-module integration.",
+          "session_id": "opencode:ses_1458206c0ffeyx0AQoGlHap1Wb",
+          "agent": "oracle",
+          "updated_at": "2026-06-12T06:23:50.560Z",
+          "started_at": "2026-06-12T06:23:50.560Z",
+          "status": "running"
+        },
+        "final-wave:f2": {
+          "task_key": "final-wave:f2",
+          "task_label": "F2",
+          "task_title": "Code Quality Review — run static analysis and review all .go files for quality issues.",
+          "session_id": "opencode:ses_145823a08ffeN5NdqAbplhAFfu",
+          "agent": "oracle",
+          "updated_at": "2026-06-12T06:23:51.328Z",
+          "started_at": "2026-06-12T06:23:51.328Z",
+          "status": "running"
+        },
+        "final-wave:f4": {
+          "task_key": "final-wave:f4",
+          "task_label": "F4",
+          "task_title": "Scope Fidelity Check — verify each task's implementation matches its spec with no scope creep.",
+          "session_id": "opencode:ses_14581c42cffeKPlQGJV5yvUNk5",
+          "agent": "oracle",
+          "updated_at": "2026-06-12T06:24:29.653Z",
+          "started_at": "2026-06-12T06:24:29.653Z",
+          "status": "running"
         }
       }
     }
@@ -153,7 +194,7 @@
   "active_plan": "/home/dailz/workspace/src/go-kv/.omo/plans/phase1-wal.md",
   "started_at": "2026-06-12T05:09:32.588Z",
   "status": "active",
-  "updated_at": "2026-06-12T06:20:06.478Z",
+  "updated_at": "2026-06-12T06:29:05.569Z",
   "session_ids": [
     "opencode:ses_145c3bae9ffeTB2zbsTym0Cev8"
   ],
@@ -291,6 +332,47 @@
       "status": "completed",
       "ended_at": "2026-06-12T06:20:06.478Z",
       "elapsed_ms": 85727
+    },
+    "final-wave:f1": {
+      "task_key": "final-wave:f1",
+      "task_label": "F1",
+      "task_title": "**Plan Compliance Audit** — `oracle`",
+      "session_id": "opencode:ses_1457cb69affe9rYiUhKWDB2kDd",
+      "agent": "Sisyphus-Junior",
+      "category": "unspecified-high",
+      "started_at": "2026-06-12T06:23:49.269Z",
+      "status": "running",
+      "updated_at": "2026-06-12T06:29:05.572Z"
+    },
+    "final-wave:f3": {
+      "task_key": "final-wave:f3",
+      "task_label": "F3",
+      "task_title": "Real Manual QA — execute all QA scenarios from the plan and verify cross-module integration.",
+      "session_id": "opencode:ses_1458206c0ffeyx0AQoGlHap1Wb",
+      "agent": "oracle",
+      "updated_at": "2026-06-12T06:23:50.560Z",
+      "started_at": "2026-06-12T06:23:50.560Z",
+      "status": "running"
+    },
+    "final-wave:f2": {
+      "task_key": "final-wave:f2",
+      "task_label": "F2",
+      "task_title": "Code Quality Review — run static analysis and review all .go files for quality issues.",
+      "session_id": "opencode:ses_145823a08ffeN5NdqAbplhAFfu",
+      "agent": "oracle",
+      "updated_at": "2026-06-12T06:23:51.328Z",
+      "started_at": "2026-06-12T06:23:51.328Z",
+      "status": "running"
+    },
+    "final-wave:f4": {
+      "task_key": "final-wave:f4",
+      "task_label": "F4",
+      "task_title": "Scope Fidelity Check — verify each task's implementation matches its spec with no scope creep.",
+      "session_id": "opencode:ses_14581c42cffeKPlQGJV5yvUNk5",
+      "agent": "oracle",
+      "updated_at": "2026-06-12T06:24:29.653Z",
+      "started_at": "2026-06-12T06:24:29.653Z",
+      "status": "running"
     }
   },
   "agent": "atlas"

memtable/memtable.go

@@ -2,6 +2,7 @@ package memtable
 
 import (
 	"errors"
+	"fmt"
 	"sync"
 	"sync/atomic"
 )
@@ -114,7 +115,11 @@ func (mt *MemTable) Publish(upToSequence uint64) {
 
 	// Re-put each entry as published. Each call acquires the skiplist mutex.
 	for _, e := range toPublish {
-		_ = mt.skiplist.Put(e.key, e.value, e.sequence, false)
+		if err := mt.skiplist.Put(e.key, e.value, e.sequence, false); err != nil {
+			// Reserve guaranteed space, so this should never happen.
+			// If it does, it's an internal invariant violation.
+			panic(fmt.Sprintf("memtable: Put failed after Reserve: %v", err))
+		}
 	}
 
 	// Update high-water mark after all entries are visible.

wal/recover.go

@@ -183,7 +183,7 @@ func findValidOffset(filePath string) (int64, error) {
 				break
 			}
 
-			rec, consumed, err := DecodePhysicalRecord(blockData[pos:])
+			_, consumed, err := DecodePhysicalRecord(blockData[pos:])
 			if err != nil {
 				// Corruption starts here — offset is up to last valid record.
 				validOffset = blockStartOffset + int64(pos)
@@ -192,8 +192,6 @@ func findValidOffset(filePath string) (int64, error) {
 
 			// Valid record found.
 			validOffset = blockStartOffset + int64(pos+consumed)
-			// Keep the rec reference alive so the compiler doesn't optimize it away.
-			_ = rec
 			pos += consumed
 		}
 

wal/segment_writer.go

@@ -19,7 +19,6 @@ type SegmentWriter struct {
 	startSequence uint64
 	blockWriter   *BlockWriter
 	currentOffset uint64 // total bytes written (starts at WalFileHeaderSize)
-	maxPayload    uint64 // cfg.MaxSegmentSize - WalFileHeaderSize
 }
 
 // NewSegmentWriter creates a new WAL segment file and writes the file header.
@@ -89,8 +88,6 @@ func NewSegmentWriter(
 		dirFD.Close()
 	}
 
-	maxPayload := cfg.MaxSegmentSize - WalFileHeaderSize
-
 	return &SegmentWriter{
 		fd:            fd,
 		dir:           dir,
@@ -99,7 +96,6 @@ func NewSegmentWriter(
 		startSequence: startSequence,
 		blockWriter:   NewBlockWriter(),
 		currentOffset: WalFileHeaderSize,
-		maxPayload:    maxPayload,
 	}, nil
 }
 
@@ -133,6 +129,9 @@ func (sw *SegmentWriter) AppendBatch(encodedBatch []byte) error {
 
 // Sync flushes the segment file to durable storage.
 func (sw *SegmentWriter) Sync() error {
+	if err := sw.blockWriter.Flush(sw.fd); err != nil {
+		return fmt.Errorf("wal: flushing partial block before sync: %w", err)
+	}
 	return sw.fd.Sync()
 }
 

wal/writer.go

@@ -145,6 +145,12 @@ func (ww *WalWriter) processBatch(requests []*CommitRequest) {
 		return
 	}
 
+	// Pre-validate encoding can succeed before sequence allocation.
+	if _, err := EncodeWalBatch(0, entries); err != nil {
+		ww.sendError(requests, err)
+		return
+	}
+
 	baseSequence, err := ww.seqManager.AllocateBatch(uint32(len(entries)))
 	if err != nil {
 		ww.sendError(requests, err)