@@ -216,10 +216,6 @@ class FirebaseMatchRepositoryImpl @Inject constructor(
216216 }
217217 }
218218
219- /* *
220- * Legacy single-field write. Kept to satisfy the interface contract and for test
221- * compatibility. In production the VM calls [commitShotAndFlipTurn] instead.
222- */
223219 override suspend fun writeShotResult (
224220 gameId : String ,
225221 shooterUid : String ,
@@ -233,44 +229,16 @@ class FirebaseMatchRepositoryImpl @Inject constructor(
233229 val pushKey = snapshot.children.elementAtOrNull(shotIndex)?.key ? : return
234230
235231 val shotNode = shotsRef.child(pushKey)
232+ // Discrete setValue calls avoid the multi-path updateChildren null/delete rule bug
236233 shotNode.child(FirebaseSchema .SHOT_RESULT ).setValue(result.toSchemaString()).await()
237- shotNode.child(FirebaseSchema .SHOT_SHIP_ID ).setValue(shipId).await()
234+ if (shipId != null ) {
235+ shotNode.child(FirebaseSchema .SHOT_SHIP_ID ).setValue(shipId).await()
236+ }
238237 } catch (e: Exception ) {
239238 Timber .w(e, " writeShotResult failed for game=$gameId shooter=$shooterUid index=$shotIndex "
240239 }
241240 }
242241
243- /* *
244- * Writes the shot result + shipId AND flips currentTurn using TWO sequential writes.
245- *
246- * ── WHY NOT a single updateChildren() from game root? ──
247- * The Firebase Security Rules for /shots/{shooterUid} grant write access ONLY to
248- * auth.uid === $shooterUid (the ATTACKER). This function is called by the DEFENDER
249- * (the person whose ships were hit). Even though the nested
250- * /shots/{shooterUid}/{pushKey}/result node has its own rule allowing the defender
251- * to write THAT specific field, a multi-path updateChildren() rooted at the game
252- * node includes paths under /shots/{shooterUid}/ — Firebase evaluates the ancestor
253- * rule (auth.uid === $shooterUid) and rejects the ENTIRE batch write for the
254- * defender. Result: result is never written, turn never flips, game is stuck.
255- *
256- * Fix: Two separate writes scoped to the exact paths each party is allowed to write:
257- * Write 1 — defender writes result + shipId directly on the shot's push-key node.
258- * The $shotPushKey parent rule allows the defender to write here
259- * (see database.rules.json — $shotPushKey allows both parties to write
260- * when the shot is unresolved, and result sub-rule allows non-shooter).
261- * Write 2 — defender writes meta/currentTurn (allowed: any authenticated player
262- * in the game may write to /meta per its .write rule).
263- *
264- * The intermediate state (result written, turn not yet flipped) is observable for
265- * ~100ms on slow connections, but this is far preferable to the turn being
266- * permanently stuck. The attacker's ViewModel guards against acting on the
267- * intermediate state: isMyTurn is set to false IMMEDIATELY when they fire (before
268- * Firebase confirms), so there is no "turn re-enables" jank on the attacker side.
269- *
270- * Firebase path writes:
271- * Call 1: games/{gameId}/shots/{shooterUid}/{pushKey}/updateChildren({result, shipId})
272- * Call 2: games/{gameId}/meta/currentTurn = nextTurnUid
273- */
274242 override suspend fun commitShotAndFlipTurn (
275243 gameId : String ,
276244 shooterUid : String ,
@@ -280,28 +248,24 @@ class FirebaseMatchRepositoryImpl @Inject constructor(
280248 nextTurnUid : String ,
281249 ): Result <Unit > {
282250 return try {
283- // ── Step 1: Resolve push-key for this shot by index ─────────────
284251 val shotsRef = database.getReference(
285252 " ${FirebaseSchema .GAMES } /$gameId /${FirebaseSchema .SHOTS } /$shooterUid "
286253 )
287254 val snapshot = shotsRef.get().await()
288255 val pushKey = snapshot.children.elementAtOrNull(shotIndex)?.key
289256 ? : return Result .failure(Exception (" Shot push-key not found at index $shotIndex "
290257
291- // ── Step 2: Write result + shipId on the shot push-key node ─────
292- // updateChildren() scoped to the push-key node — the defender is allowed
293- // to write result here per security rules. shipId inherits the push-key
294- // node's rule which now permits non-shooter writes (see database.rules.json).
295258 val shotNodeRef = shotsRef.child(pushKey)
296- val shotUpdate = mapOf<String , Any ?>(
297- FirebaseSchema .SHOT_RESULT to result.toSchemaString(),
298- FirebaseSchema .SHOT_SHIP_ID to shipId,
299- )
300- shotNodeRef.updateChildren(shotUpdate).await()
259+
260+ // ── Step 1: Write result ─────────────────────────────────────────
261+ shotNodeRef.child(FirebaseSchema .SHOT_RESULT ).setValue(result.toSchemaString()).await()
262+
263+ // ── Step 2: Write shipId ONLY if not null ────────────────────────
264+ if (shipId != null ) {
265+ shotNodeRef.child(FirebaseSchema .SHOT_SHIP_ID ).setValue(shipId).await()
266+ }
301267
302- // ── Step 3: Flip currentTurn to the defender ────────────────────
303- // nextTurnUid = myUid on the defender's device (it becomes the defender's
304- // turn to fire after they resolve the attacker's shot).
268+ // ── Step 3: Flip currentTurn to the defender ─────────────────────
305269 database.getReference(
306270 " ${FirebaseSchema .GAMES } /$gameId /${FirebaseSchema .META } /${FirebaseSchema .CURRENT_TURN } "
307271 ).setValue(nextTurnUid).await()
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