Add request ID support to `DBAPI`

sources/Data/Database/DBTask.uc

@@ -6,7 +6,7 @@
  *  completed and will self-destruct afterwards. Concrete delegates are
  *  declared in child classes of this `DBTask`, since they can have different
  *  signatures, depending on the query.
- *      Copyright 2021 Anton Tarasenko
+ *      Copyright 2021-2023 Anton Tarasenko
  *------------------------------------------------------------------------------
  * This file is part of Acedia.
  *
@@ -54,6 +54,7 @@ var private int     previousTaskLifeVersion;
 
 var private Database.DBQueryResult  taskResult;
 var private bool                    isReadyToComplete;
+var private int                     requestID;
 
 var private LoggerAPI.Definition errLoopInTaskChain;
 
@@ -65,6 +66,18 @@ protected function Finalizer()
     previousTask            = none;
     previousTaskLifeVersion = -1;
     isReadyToComplete       = false;
+    requestID               = 0;
+}
+
+/**
+ *  Returns ID of the request set inside `SetResult()` for the caller `DBTask`.
+ *
+ *  @return ID of the request set inside `SetResult()` for the caller `DBTask`.
+ *      If `SetResult()` wasn't yet called returns `0`.
+ */
+protected function int GetRequestID()
+{
+    return requestID;
 }
 
 /**
@@ -105,12 +118,17 @@ public final function Database.DBQueryResult GetResult()
  *  This value can be assigned several times and the last assigned value will
  *  be used.
  *
- *  @param  result  Result of the query, relevant to the caller task.
+ *  @param  result      Result of the query, relevant to the caller task.
+ *  @param  requestID   ID of the request this task is responding to, specified
+ *      at the time request was made.
  */
-public final function SetResult(Database.DBQueryResult result)
+public final function SetResult(
+    Database.DBQueryResult  result,
+    optional int            completedRequestID)
 {
     taskResult          = result;
     isReadyToComplete   = true;
+    requestID           = completedRequestID;
 }
 
 /**

sources/Data/Database/Database.uc

@@ -7,7 +7,7 @@
  *      All of the methods are asynchronous - they do not return requested
  *  values immediately and instead require user to provide a handler function
  *  that will be called once operation is completed.
- *      Copyright 2021-2022 Anton Tarasenko
+ *      Copyright 2021-2023 Anton Tarasenko
  *------------------------------------------------------------------------------
  * This file is part of Acedia.
  *
@@ -73,15 +73,27 @@ enum DBQueryResult
  *      to load data as immutable Acedia's types and `true` will make it load
  *      data as mutable types. This setting does not affect `Collection`s into
  *      which JSON arrays and objects are converted - they are always mutable.
+ *  @param  requestID       ID of this request. It will be reported when
+ *      database's task is completed. Can be used to correspond database's
+ *      responses with particular requests.
  *  @return Task object that corresponds to this `ReadData()` call.
  *      *   Guaranteed to be not `none`;
  *      *   Use it to connect a handler for when reading task is complete:
- *              `ReadData(...).connect = handler`,
- *              where `handler` must have the following signature:
- *              `connect(DBQueryResult result, AcediaObject data)`;
+ *          `ReadData(...).connect = handler`,
+ *          where `handler` must have the following signature:
+ *          ```
+ *          connect(
+ *              DBQueryResult       result,
+ *              take AcediaObject   data,
+ *              Database            source,
+ *              int                 requestID)`;
+ *          ```
  *      *   Ownership of `data` object returned in the `connect()` is considered
  *          to be transferred to whoever handled result of this query.
  *          It must be deallocated once no longer needed.
+ *      *   `source` provides reference to the database, whose data was
+ *          requested, `requestID` provides the same number as `requestID`
+ *          parameter of this method.
  *      *   Possible `DBQueryResult` types are `DBR_Success`,
  *          `DBR_InvalidPointer` and `DBR_InvalidDatabase`;
  *      *   `data` is guaranteed to be `none` if `result != DBR_Success`;
@@ -90,7 +102,8 @@ enum DBQueryResult
  */
 public function DBReadTask ReadData(
     JSONPointer     pointer,
-    optional bool   makeMutable)
+    optional bool   makeMutable,
+    optional int    requestID)
 {
     return none;
 }
@@ -110,12 +123,18 @@ public function DBReadTask ReadData(
  *  @param  data    Data that needs to be written at the specified location
  *      inside the database. For method to succeed this object needs to have
  *      JSON-compatible type (see `_.json.IsCompatible()` for more details).
+ *  @param  requestID       ID of this request. It will be reported when
+ *      database's task is completed. Can be used to correspond database's
+ *      responses with particular requests.
  *  @return Task object that corresponds to this `WriteData()` call.
  *      *   Guaranteed to be not `none`;
  *      *   Use it to connect a handler for when writing task is complete:
  *          `WriteData(...).connect = handler`,
  *          where `handler` must have the following signature:
- *          `connect(DBQueryResult result)`;
+ *          `connect(DBQueryResult result, Database source, int requestID)`;
+ *      *   `source` provides reference to the database, whose data was
+ *          requested, `requestID` provides the same number as `requestID`
+ *          parameter of this method.
  *      *   Possible `DBQueryResult` types are `DBR_Success`,
  *          `DBR_InvalidPointer`, `DBR_InvalidDatabase` and `DBR_InvalidData`;
  *      *   Data is actually written inside the database iff
@@ -128,7 +147,10 @@ public function DBReadTask ReadData(
  *          Example: writing data at "/sub-object/valueA" will always fail if
  *          "sub-object" does not exist.
  */
-public function DBWriteTask WriteData(JSONPointer pointer, AcediaObject data)
+public function DBWriteTask WriteData(
+    JSONPointer     pointer,
+    AcediaObject    data,
+    optional int    requestID)
 {
     return none;
 }
@@ -141,12 +163,18 @@ public function DBWriteTask WriteData(JSONPointer pointer, AcediaObject data)
  *
  *  @param  pointer JSON pointer to the location of the data to remove from
  *      database. `none` is always treated as an invalid JSON pointer.
+ *  @param  requestID       ID of this request. It will be reported when
+ *      database's task is completed. Can be used to correspond database's
+ *      responses with particular requests.
  *  @return Task object that corresponds to this `RemoveData()` call.
  *      *   Guaranteed to be not `none`;
  *      *   Use it to connect a handler for when writing task is complete:
  *          `RemoveData(...).connect = handler`,
  *          where `handler` must have the following signature:
- *          `connect(DBQueryResult result)`.
+ *          `connect(DBQueryResult result, Database source, int requestID)`.
+ *      *   `source` provides reference to the database, whose data was
+ *          requested, `requestID` provides the same number as `requestID`
+ *          parameter of this method.
  *      *   Possible `DBQueryResult` types are `DBR_Success`,
  *          `DBR_InvalidPointer` and `DBR_InvalidDatabase`;
  *      *   Data is actually removed from the database iff
@@ -154,7 +182,9 @@ public function DBWriteTask WriteData(JSONPointer pointer, AcediaObject data)
  *      *   `DBR_InvalidPointer` can be produced if either `pointer == none` or
  *          it does not point at any existing value inside the caller database.
  */
-public function DBRemoveTask RemoveData(JSONPointer pointer)
+public function DBRemoveTask RemoveData(
+    JSONPointer     pointer,
+    optional int    requestID)
 {
     return none;
 }
@@ -166,12 +196,24 @@ public function DBRemoveTask RemoveData(JSONPointer pointer)
  *  @param  pointer JSON pointer to the location of the data for which type
  *      needs to be checked.
  *      `none` is always treated as an invalid JSON pointer.
+ *  @param  requestID       ID of this request. It will be reported when
+ *      database's task is completed. Can be used to correspond database's
+ *      responses with particular requests.
  *  @return Task object that corresponds to this `CheckDataType()` call.
  *      *   Guaranteed to be not `none`;
  *      *   Use it to connect a handler for when reading task is complete:
  *          `CheckDataType(...).connect = handler`,
  *          where `handler` must have the following signature:
- *          `connect(DBQueryResult result, Database.DataType type)`;
+ *          ```
+ *          connect(
+ *              DBQueryResult       result,
+ *              Database.DataType   type,
+ *              Database            source,
+ *              int                 requestID)
+ *          ```
+ *      *   `source` provides reference to the database, whose data was
+ *          requested, `requestID` provides the same number as `requestID`
+ *          parameter of this method.
  *      *   Possible `DBQueryResult` types are `DBR_Success`,
  *          `DBR_InvalidPointer` and `DBR_InvalidDatabase`;
  *      *   This task can only fail if either caller database is broken
@@ -181,7 +223,9 @@ public function DBRemoveTask RemoveData(JSONPointer pointer)
  *      *   Data is actually removed from the database iff
  *          `result == DBR_Success`.
  */
-public function DBCheckTask CheckDataType(JSONPointer pointer)
+public function DBCheckTask CheckDataType(
+    JSONPointer     pointer,
+    optional int    requestID)
 {
     return none;
 }
@@ -197,12 +241,24 @@ public function DBCheckTask CheckDataType(JSONPointer pointer)
  *  @param  pointer JSON pointer to the location of the JSON object or array
  *      for which size needs to be obtained.
  *      `none` is always treated as an invalid JSON pointer.
+ *  @param  requestID       ID of this request. It will be reported when
+ *      database's task is completed. Can be used to correspond database's
+ *      responses with particular requests.
  *  @return Task object that corresponds to this `GetDataSize()` call.
  *      *   Guaranteed to be not `none`;
  *      *   Use it to connect a handler for when reading task is complete:
  *          `GetDataSize(...).connect = handler`,
  *          where `handler` must have the following signature:
- *          `connect(DBQueryResult result, int size)`.
+ *          ```
+ *          connect(
+ *              DBQueryResult   result,
+ *              int             size,
+ *              Database        source,
+ *              int             requestID)
+ *          ```
+ *      *   `source` provides reference to the database, whose data was
+ *          requested, `requestID` provides the same number as `requestID`
+ *          parameter of this method.
  *      *   Possible `DBQueryResult` types are `DBR_Success`,
  *          `DBR_InvalidPointer` and `DBR_InvalidDatabase`;
  *      *   Returned `size` value is actually a size of referred
@@ -211,7 +267,9 @@ public function DBCheckTask CheckDataType(JSONPointer pointer)
  *          it does not point at a JSON object or array inside the
  *          caller database.
  */
-public function DBSizeTask GetDataSize(JSONPointer pointer)
+public function DBSizeTask GetDataSize(
+    JSONPointer     pointer,
+    optional int    requestID)
 {
     return none;
 }
@@ -225,15 +283,27 @@ public function DBSizeTask GetDataSize(JSONPointer pointer)
  *  @param  pointer JSON pointer to the location of the JSON object for which
  *      keys need to be obtained.
  *      `none` is always treated as an invalid JSON pointer.
+ *  @param  requestID       ID of this request. It will be reported when
+ *      database's task is completed. Can be used to correspond database's
+ *      responses with particular requests.
  *  @return Task object that corresponds to this `GetDataKeys()` call.
  *      *   Guaranteed to be not `none`;
  *      *   Use it to connect a handler for when reading task is complete:
  *          `GetDataKeys(...).connect = handler`,
  *          where `handler` must have the following signature:
- *          `connect(DBQueryResult result, ArrayList keys)`.
+ *          ```
+ *          connect(
+ *              DBQueryResult   result,
+ *              take ArrayList  keys,
+ *              Database        source,
+ *              int             requestID)
+ *          ```
  *      *   Ownership of `keys` array returned in the `connect()` is considered
  *          to be transferred to whoever handled result of this query.
  *          It must be deallocated once no longer needed.
+ *      *   `source` provides reference to the database, whose data was
+ *          requested, `requestID` provides the same number as `requestID`
+ *          parameter of this method.
  *      *   Possible `DBQueryResult` types are `DBR_Success`,
  *          `DBR_InvalidPointer`, `DBR_InvalidData` and `DBR_InvalidDatabase`;
  *      *   Returned `keys` will be non-`none` and contain keys of the referred
@@ -243,7 +313,9 @@ public function DBSizeTask GetDataSize(JSONPointer pointer)
  *          point at a JSON object inside caller database
  *          (value can either not exist at all or have some other type).
  */
-public function DBKeysTask GetDataKeys(JSONPointer pointer)
+public function DBKeysTask GetDataKeys(
+    JSONPointer     pointer,
+    optional int    requestID)
 {
     return none;
 }
@@ -255,19 +327,21 @@ public function DBKeysTask GetDataKeys(JSONPointer pointer)
  *  "Incrementing" is an operation that is safe from the point of view of
  *  simultaneous access. What "incrementing" actually does depends on
  *  the passed JSON value (`increment` parameter):
- *      (0.  Unless `pointer` points at the JSON null value - then "increment"
- *          acts as a `WriteData()` method regardless of `increment`'s value);
+ *
+ *      (0. ...unless `pointer` points at the JSON null or missing value (within
+ *          existing container - then "increment" acts as a `WriteData()` method
+ *          regardless of `increment`'s value;)
  *      1.  JSON null: it never modifies existing value and reports an error if
  *          existing value was not itself JSON null;
- *      2.  JSON bool: if combines with stored JSON bool value -
+ *      2.  JSON bool: if combined with stored JSON bool value -
  *          performs logical "or" operation. Otherwise fails;
- *      3. JSON number: if combines with stored JSON numeric value -
+ *      3.  JSON number: if combined with stored JSON numeric value -
  *          adds values together. Otherwise fails.
- *      4. JSON string: if combines with stored JSON string value -
+ *      4.  JSON string: if combined with stored JSON string value -
  *          concatenates itself at the end. Otherwise fails.
- *      5. JSON array: if combines with stored JSON array value -
+ *      5.  JSON array: if combined with stored JSON array value -
  *          concatenates itself at the end. Otherwise fails.
- *      6. JSON object: if combines with stored JSON object value -
+ *      6.  JSON object: if combined with stored JSON object value -
  *          `increment` adds it's own values with new keys into the stored
  *          JSON object. Does not override old values.
  *          Fails when combined with any other type.
@@ -280,12 +354,18 @@ public function DBKeysTask GetDataKeys(JSONPointer pointer)
  *      with `increment` parameter.
  *  @param  increment   JSON-compatible value to be used as an increment for
  *      the data at the specified location inside the database.
+ *  @param  requestID       ID of this request. It will be reported when
+ *      database's task is completed. Can be used to correspond database's
+ *      responses with particular requests.
  *  @return Task object that corresponds to this `IncrementData()` call.
  *      *   Guaranteed to be not `none`;
  *      *   Use it to connect a handler for when reading task is complete:
  *          `IncrementData(...).connect = handler`,
  *          where `handler` must have the following signature:
- *          `connect(DBQueryResult result)`.
+ *          `connect(DBQueryResult result, Database source, int requestID)`.
+ *      *   `source` provides reference to the database, whose data was
+ *          requested, `requestID` provides the same number as `requestID`
+ *          parameter of this method.
  *      *   Possible `DBQueryResult` types are `DBR_Success`,
  *          `DBR_InvalidPointer`, `DBR_InvalidData` and `DBR_InvalidDatabase`;
  *      *   Data is actually incremented iff `result == DBR_Success`;
@@ -299,7 +379,8 @@ public function DBKeysTask GetDataKeys(JSONPointer pointer)
  */
 public function DBIncrementTask IncrementData(
     JSONPointer     pointer,
-    AcediaObject    increment)
+    AcediaObject    increment,
+    optional int    requestID)
 {
     return none;
 }

sources/Data/Database/Local/LocalDatabaseInstance.uc

@@ -149,54 +149,61 @@ private final function DBTask MakeNewTask(class<DBTask> newTaskClass)
     return newTask;
 }
 
-private function bool ValidatePointer(JSONPointer pointer, DBTask relevantTask)
+private function bool ValidatePointer(
+    JSONPointer pointer,
+    DBTask      relevantTask,
+    int         requestID)
 {
     if (pointer != none) {
         return true;
     }
-    relevantTask.SetResult(DBR_InvalidPointer);
+    relevantTask.SetResult(DBR_InvalidPointer, requestID);
     return false;
 }
 
-private function bool ValidateRootRecord(DBTask relevantTask)
+private function bool ValidateRootRecord(DBTask relevantTask, int requestID)
 {
     if (rootRecord != none) {
         return true;
     }
-    relevantTask.SetResult(DBR_InvalidDatabase);
+    relevantTask.SetResult(DBR_InvalidDatabase, requestID);
     return false;
 }
 
 public function DBReadTask ReadData(
     JSONPointer     pointer,
-    optional bool   makeMutable)
+    optional bool   makeMutable,
+    optional int    requestID)
 {
     local AcediaObject  queryResult;
     local DBReadTask    readTask;
     readTask = DBReadTask(MakeNewTask(class'DBReadTask'));
-    if (!ValidatePointer(pointer, readTask))    return readTask;
-    if (!ValidateRootRecord(readTask))          return readTask;
+    if (!ValidatePointer(pointer, readTask, requestID)) return readTask;
+    if (!ValidateRootRecord(readTask, requestID))       return readTask;
 
     if (rootRecord.LoadObject(pointer, queryResult, makeMutable))
     {
         readTask.SetReadData(queryResult);
-        readTask.SetResult(DBR_Success);
+        readTask.SetResult(DBR_Success, requestID);
     }
     else
     {
-        readTask.SetResult(DBR_InvalidPointer);
+        readTask.SetResult(DBR_InvalidPointer, requestID);
         _.memory.Free(queryResult); //  just in case
     }
     return readTask;
 }
 
-public function DBWriteTask WriteData(JSONPointer pointer, AcediaObject data)
+public function DBWriteTask WriteData(
+    JSONPointer     pointer,
+    AcediaObject    data,
+    optional int    requestID)
 {
     local bool          isDataStorable;
     local DBWriteTask   writeTask;
     writeTask = DBWriteTask(MakeNewTask(class'DBWriteTask'));
-    if (!ValidatePointer(pointer, writeTask))   return writeTask;
-    if (!ValidateRootRecord(writeTask))         return writeTask;
+    if (!ValidatePointer(pointer, writeTask, requestID))    return writeTask;
+    if (!ValidateRootRecord(writeTask, requestID))          return writeTask;
 
     //  We can only write JSON array as the root value
     if (data != none && pointer.GetLength() <= 0) {
@@ -207,99 +214,111 @@ public function DBWriteTask WriteData(JSONPointer pointer, AcediaObject data)
     }
     if (!isDataStorable)
     {
-        writeTask.SetResult(DBR_InvalidData);
+        writeTask.SetResult(DBR_InvalidData, requestID);
         return writeTask;
     }
     if (rootRecord.SaveObject(pointer, data))
     {
-        writeTask.SetResult(DBR_Success);
+        writeTask.SetResult(DBR_Success, requestID);
         ScheduleDiskUpdate();
     }
     else {
-        writeTask.SetResult(DBR_InvalidPointer);
+        writeTask.SetResult(DBR_InvalidPointer, requestID);
     }
     return writeTask;
 }
 
-public function DBRemoveTask RemoveData(JSONPointer pointer)
+public function DBRemoveTask RemoveData(
+    JSONPointer     pointer,
+    optional int    requestID)
 {
     local DBRemoveTask removeTask;
     removeTask = DBRemoveTask(MakeNewTask(class'DBRemoveTask'));
-    if (!ValidatePointer(pointer, removeTask))  return removeTask;
-    if (!ValidateRootRecord(removeTask))        return removeTask;
+    if (!ValidatePointer(pointer, removeTask, requestID))   return removeTask;
+    if (!ValidateRootRecord(removeTask, requestID))         return removeTask;
 
     if (pointer.GetLength() == 0)
     {
         rootRecord.EmptySelf();
-        removeTask.SetResult(DBR_Success);
+        removeTask.SetResult(DBR_Success, requestID);
         return removeTask;
     }
     if (rootRecord.RemoveObject(pointer))
     {
-        removeTask.SetResult(DBR_Success);
+        removeTask.SetResult(DBR_Success, requestID);
         ScheduleDiskUpdate();
     }
     else {
-        removeTask.SetResult(DBR_InvalidPointer);
+        removeTask.SetResult(DBR_InvalidPointer, requestID);
     }
     return removeTask;
 }
 
-public function DBCheckTask CheckDataType(JSONPointer pointer)
+public function DBCheckTask CheckDataType(
+    JSONPointer     pointer,
+    optional int    requestID)
 {
     local DBCheckTask checkTask;
     checkTask = DBCheckTask(MakeNewTask(class'DBCheckTask'));
-    if (!ValidatePointer(pointer, checkTask))   return checkTask;
-    if (!ValidateRootRecord(checkTask))         return checkTask;
+    if (!ValidatePointer(pointer, checkTask, requestID))    return checkTask;
+    if (!ValidateRootRecord(checkTask, requestID))          return checkTask;
 
     checkTask.SetDataType(rootRecord.GetObjectType(pointer));
-    checkTask.SetResult(DBR_Success);
+    checkTask.SetResult(DBR_Success, requestID);
     return checkTask;
 }
 
-public function DBSizeTask GetDataSize(JSONPointer pointer)
+public function DBSizeTask GetDataSize(
+    JSONPointer     pointer,
+    optional int    requestID)
 {
     local DBSizeTask sizeTask;
     sizeTask = DBSizeTask(MakeNewTask(class'DBSizeTask'));
-    if (!ValidatePointer(pointer, sizeTask))    return sizeTask;
-    if (!ValidateRootRecord(sizeTask))          return sizeTask;
+    if (!ValidatePointer(pointer, sizeTask, requestID)) return sizeTask;
+    if (!ValidateRootRecord(sizeTask, requestID))       return sizeTask;
 
     sizeTask.SetDataSize(rootRecord.GetObjectSize(pointer));
-    sizeTask.SetResult(DBR_Success);
+    sizeTask.SetResult(DBR_Success, requestID);
     return sizeTask;
 }
 
-public function DBKeysTask GetDataKeys(JSONPointer pointer)
+public function DBKeysTask GetDataKeys(
+    JSONPointer     pointer,
+    optional int    requestID)
 {
     local ArrayList     keys;
     local DBKeysTask    keysTask;
     keysTask = DBKeysTask(MakeNewTask(class'DBKeysTask'));
-    if (!ValidatePointer(pointer, keysTask))    return keysTask;
-    if (!ValidateRootRecord(keysTask))          return keysTask;
+    if (!ValidatePointer(pointer, keysTask, requestID)) return keysTask;
+    if (!ValidateRootRecord(keysTask, requestID))       return keysTask;
 
     keys = rootRecord.GetObjectKeys(pointer);
     keysTask.SetDataKeys(keys);
     if (keys == none) {
-        keysTask.SetResult(DBR_InvalidData);
+        keysTask.SetResult(DBR_InvalidData, requestID);
     }
     else {
-        keysTask.SetResult(DBR_Success);
+        keysTask.SetResult(DBR_Success, requestID);
     }
     return keysTask;
 }
 
 public function DBIncrementTask IncrementData(
     JSONPointer     pointer,
-    AcediaObject    increment)
+    AcediaObject    increment,
+    optional int    requestID)
 {
     local DBQueryResult     queryResult;
     local DBIncrementTask   incrementTask;
     incrementTask = DBIncrementTask(MakeNewTask(class'DBIncrementTask'));
-    if (!ValidatePointer(pointer, incrementTask))   return incrementTask;
-    if (!ValidateRootRecord(incrementTask))         return incrementTask;
-
+    if (!ValidatePointer(pointer, incrementTask, requestID)) {
+        return incrementTask;
+    }
+    if (!ValidateRootRecord(incrementTask, requestID)) {
+        return incrementTask;
+    }
     queryResult = rootRecord.IncrementObject(pointer, increment);
-    incrementTask.SetResult(queryResult);
+    incrementTask.SetResult(queryResult, requestID);
     if (queryResult == DBR_Success) {
         ScheduleDiskUpdate();
     }

sources/Data/Database/Tasks/DBCheckTask.uc

@@ -1,6 +1,6 @@
 /**
  *  Variant of `DBTask` for `CheckDataType()` query.
- *      Copyright 2021 Anton Tarasenko
+ *      Copyright 2021-2023 Anton Tarasenko
  *------------------------------------------------------------------------------
  * This file is part of Acedia.
  *
@@ -24,7 +24,8 @@ var private Database.DataType queryTypeResponse;
 delegate connect(
     Database.DBQueryResult  result,
     Database.DataType       type,
-    Database                source) {}
+    Database                source,
+    int                     requestID) {}
 
 protected function Finalizer()
 {
@@ -40,7 +41,7 @@ public function SetDataType(Database.DataType type)
 
 protected function CompleteSelf(Database source)
 {
-    connect(GetResult(), queryTypeResponse, source);
+    connect(GetResult(), queryTypeResponse, source, GetRequestID());
 }
 
 defaultproperties

sources/Data/Database/Tasks/DBIncrementTask.uc

@@ -1,6 +1,6 @@
 /**
  *  Variant of `DBTask` for `IncrementData()` query.
- *      Copyright 2021 Anton Tarasenko
+ *      Copyright 2021-2023 Anton Tarasenko
  *------------------------------------------------------------------------------
  * This file is part of Acedia.
  *
@@ -19,7 +19,10 @@
  */
 class DBIncrementTask extends DBTask;
 
-delegate connect(Database.DBQueryResult result, Database source) {}
+delegate connect(
+    Database.DBQueryResult  result,
+    Database                source,
+    int                     requestID) {}
 
 protected function Finalizer()
 {
@@ -29,7 +32,7 @@ protected function Finalizer()
 
 protected function CompleteSelf(Database source)
 {
-    connect(GetResult(), source);
+    connect(GetResult(), source, GetRequestID());
 }
 
 defaultproperties

sources/Data/Database/Tasks/DBKeysTask.uc

@@ -1,6 +1,6 @@
 /**
  *  Variant of `DBTask` for `GetDataKeys()` query.
- *      Copyright 2021-2022 Anton Tarasenko
+ *      Copyright 2021-2023 Anton Tarasenko
  *------------------------------------------------------------------------------
  * This file is part of Acedia.
  *
@@ -23,8 +23,9 @@ var private ArrayList queryKeysResponse;
 
 delegate connect(
     Database.DBQueryResult  result,
-    ArrayList               keys,
-    Database                source) {}
+    /*take*/ ArrayList      keys,
+    Database                source,
+    int                     requestID) {}
 
 protected function Finalizer()
 {
@@ -40,7 +41,7 @@ public function SetDataKeys(/* take */ ArrayList keys)
 
 protected function CompleteSelf(Database source)
 {
-    connect(GetResult(), queryKeysResponse, source);
+    connect(GetResult(), queryKeysResponse, source, GetRequestID());
 }
 
 defaultproperties

sources/Data/Database/Tasks/DBReadTask.uc

@@ -1,6 +1,6 @@
 /**
  *  Variant of `DBTask` for `ReadData()` query.
- *      Copyright 2021 Anton Tarasenko
+ *      Copyright 2021-2023 Anton Tarasenko
  *------------------------------------------------------------------------------
  * This file is part of Acedia.
  *
@@ -23,8 +23,9 @@ var private AcediaObject queryDataResponse;
 
 delegate connect(
     Database.DBQueryResult  result,
-    AcediaObject            data,
-    Database                source) {}
+    /*take*/ AcediaObject   data,
+    Database                source,
+    int                     requestID) {}
 
 protected function Finalizer()
 {
@@ -40,7 +41,7 @@ public function SetReadData(AcediaObject data)
 
 protected function CompleteSelf(Database source)
 {
-    connect(GetResult(), queryDataResponse, source);
+    connect(GetResult(), queryDataResponse, source, GetRequestID());
 }
 
 defaultproperties

sources/Data/Database/Tasks/DBRemoveTask.uc

@@ -1,6 +1,6 @@
 /**
  *  Variant of `DBTask` for `RemoveData()` query.
- *      Copyright 2021 Anton Tarasenko
+ *      Copyright 2021-2023 Anton Tarasenko
  *------------------------------------------------------------------------------
  * This file is part of Acedia.
  *
@@ -19,7 +19,10 @@
  */
 class DBRemoveTask extends DBTask;
 
-delegate connect(Database.DBQueryResult result, Database source) {}
+delegate connect(
+    Database.DBQueryResult  result,
+    Database                source,
+    int                     requestID) {}
 
 protected function Finalizer()
 {
@@ -29,7 +32,7 @@ protected function Finalizer()
 
 protected function CompleteSelf(Database source)
 {
-    connect(GetResult(), source);
+    connect(GetResult(), source, GetRequestID());
 }
 
 defaultproperties

sources/Data/Database/Tasks/DBSizeTask.uc

@@ -1,6 +1,6 @@
 /**
  *  Variant of `DBTask` for `GetDataSize()` query.
- *      Copyright 2021 Anton Tarasenko
+ *      Copyright 2021-2023 Anton Tarasenko
  *------------------------------------------------------------------------------
  * This file is part of Acedia.
  *
@@ -21,7 +21,11 @@ class DBSizeTask extends DBTask;
 
 var private int querySizeResponse;
 
-delegate connect(Database.DBQueryResult result, int size, Database source) {}
+delegate connect(
+    Database.DBQueryResult  result,
+    int                     size,
+    Database                source,
+    int                     requestID) {}
 
 protected function Finalizer()
 {
@@ -37,7 +41,7 @@ public function SetDataSize(int size)
 
 protected function CompleteSelf(Database source)
 {
-    connect(GetResult(), querySizeResponse, source);
+    connect(GetResult(), querySizeResponse, source, GetRequestID());
 }
 
 defaultproperties

sources/Data/Database/Tasks/DBWriteTask.uc

@@ -1,6 +1,6 @@
 /**
  *  Variant of `DBTask` for `WriteData()` query.
- *      Copyright 2021 Anton Tarasenko
+ *      Copyright 2021-2023 Anton Tarasenko
  *------------------------------------------------------------------------------
  * This file is part of Acedia.
  *
@@ -19,7 +19,10 @@
  */
 class DBWriteTask extends DBTask;
 
-delegate connect(Database.DBQueryResult result, Database source) {}
+delegate connect(
+    Database.DBQueryResult  result,
+    Database                source,
+    int                     requestID) {}
 
 protected function Finalizer()
 {
@@ -29,7 +32,7 @@ protected function Finalizer()
 
 protected function CompleteSelf(Database source)
 {
-    connect(GetResult(), source);
+    connect(GetResult(), source, GetRequestID());
 }
 
 defaultproperties

sources/Data/Database/Tests/TEST_DatabaseCommon.uc

@@ -25,20 +25,20 @@ protected static function TESTS()
     local JSONPointer pointer;
     Context("Testing extracting `JSONPointer` from database link.");
     Issue("`JSONPointer` is incorrectly extracted.");
-    pointer = __().db.GetPointer(
+    pointer = __core().db.GetPointer(
         __().text.FromString("[local]default:/huh/what/is/"));
     TEST_ExpectNotNone(pointer);
     TEST_ExpectTrue(pointer.ToText().ToString() == "/huh/what/is/");
-    pointer = __().db.GetPointer(__().text.FromString("[remote]db:"));
+    pointer = __core().db.GetPointer(__().text.FromString("[remote]db:"));
     TEST_ExpectNotNone(pointer);
     TEST_ExpectTrue(pointer.ToText().ToString() == "");
-    pointer = __().db.GetPointer(__().text.FromString("[remote]:"));
+    pointer = __core().db.GetPointer(__().text.FromString("[remote]:"));
     TEST_ExpectNotNone(pointer);
     TEST_ExpectTrue(pointer.ToText().ToString() == "");
-    pointer = __().db.GetPointer(__().text.FromString("db:/just/a/pointer"));
+    pointer = __core().db.GetPointer(__().text.FromString("db:/just/a/pointer"));
     TEST_ExpectNotNone(pointer);
     TEST_ExpectTrue(pointer.ToText().ToString() == "/just/a/pointer");
-    pointer = __().db.GetPointer(__().text.FromString(":/just/a/pointer"));
+    pointer = __core().db.GetPointer(__().text.FromString(":/just/a/pointer"));
     TEST_ExpectNotNone(pointer);
     TEST_ExpectTrue(pointer.ToText().ToString() == "/just/a/pointer");
 }

sources/Data/Database/Tests/TEST_LocalDatabase.uc

@@ -27,63 +27,78 @@ var protected Database.DBQueryResult    resultType;
 var protected Database.DataType         resultDataType;
 var protected HashTable                 resultData;
 var protected AcediaObject              resultObject;
+var protected int                       resultRequestID;
 
 protected function DBReadingHandler(
     Database.DBQueryResult  result,
     AcediaObject            data,
-    Database                source)
+    Database                source,
+    int                     requestID)
 {
     default.resultType      = result;
     default.resultObject    = data;
     default.resultData      = HashTable(data);
+    default.resultRequestID = requestID;
 }
 
 protected function DBKeysHandler(
     Database.DBQueryResult  result,
     ArrayList               keys,
-    Database                source)
+    Database                source,
+    int                     requestID)
 {
-    default.resultType = result;
-    default.resultKeys = keys;
+    default.resultType      = result;
+    default.resultKeys      = keys;
+    default.resultRequestID = requestID;
 }
 
 protected function DBCheckHandler(
     Database.DBQueryResult  result,
     Database.DataType       type,
-    Database                source)
+    Database                source,
+    int                     requestID)
 {
-    default.resultType = result;
-    default.resultDataType = type;
+    default.resultType      = result;
+    default.resultDataType  = type;
+    default.resultRequestID = requestID;
 }
 
 protected function DBSizeHandler(
     Database.DBQueryResult  result,
     int                     size,
-    Database                source)
+    Database                source,
+    int                     requestID)
 {
-    default.resultType = result;
-    default.resultSize = size;
+    default.resultType      = result;
+    default.resultSize      = size;
+    default.resultRequestID = requestID;
 }
 
 protected function DBWritingHandler(
     Database.DBQueryResult  result,
-    Database                source)
+    Database                source,
+    int                     requestID)
 {
-    default.resultType = result;
+    default.resultType      = result;
+    default.resultRequestID = requestID;
 }
 
 protected function DBIncrementHandler(
     Database.DBQueryResult  result,
-    Database                source)
+    Database                source,
+    int                     requestID)
 {
-    default.resultType = result;
+    default.resultType      = result;
+    default.resultRequestID = requestID;
 }
 
 protected function DBRemoveHandler(
     Database.DBQueryResult  result,
-    Database                source)
+    Database                source,
+    int                     requestID)
 {
-    default.resultType = result;
+    default.resultType      = result;
+    default.resultRequestID = requestID;
 }
 
 protected static function ReadFromDB(LocalDatabaseInstance db, string pointer)
@@ -117,7 +132,7 @@ local LocalDatabaseInstance db;
 source = GetJSONTemplateString();
 parser = __().text.ParseString(source);
 root = HashTable(__().json.ParseWith(parser));
-db = __().db.NewLocal(P("TEST_ReadOnly"));
+db = __core().db.NewLocal(P("TEST_ReadOnly"));
 db.WriteData(__().json.Pointer(), root);
 */
 protected static function string GetJSONTemplateString()
@@ -220,19 +235,20 @@ protected static function TESTS()
     Test_TaskChaining();
     Test_Removal();
     Test_Increment();
+    Test_RequestID();
 }
 
 protected static function Test_LoadingPrepared()
 {
     local LocalDatabaseInstance db;
-    db = __().db.LoadLocal(P("TEST_ReadOnly"));
+    db = __core().db.LoadLocal(P("TEST_ReadOnly"));
     Context("Testing reading prepared data from the local database.");
     Issue("Existing database reported as missing.");
-    TEST_ExpectTrue(__().db.ExistsLocal(P("TEST_ReadOnly")));
+    TEST_ExpectTrue(__core().db.ExistsLocal(P("TEST_ReadOnly")));
 
     Issue("Loading same database several times produces different"
         @ "`LocalDatabaseInstance` objects.");
-    TEST_ExpectTrue(__().db.LoadLocal(P("TEST_ReadOnly")) ==  db);
+    TEST_ExpectTrue(__core().db.LoadLocal(P("TEST_ReadOnly")) ==  db);
     //  Groups of read-only tests
     SubTest_LoadingPreparedSuccessRoot(db);
     SubTest_LoadingPreparedSuccessSubValues(db);
@@ -471,18 +487,18 @@ protected static function SubTest_LoadingPreparedGetKeysFail(
 protected static function Test_Writing()
 {
     local LocalDatabaseInstance db;
-    db = __().db.NewLocal(P("TEST_DB"));
+    db = __core().db.NewLocal(P("TEST_DB"));
     Context("Testing (re-)creating and writing into a new local database.");
     Issue("Cannot create a new database.");
     TEST_ExpectNotNone(db);
-    TEST_ExpectTrue(__().db.ExistsLocal(P("TEST_DB")));
+    TEST_ExpectTrue(__core().db.ExistsLocal(P("TEST_DB")));
 
     Issue("Freshly created database is not empty.");
     TEST_ExpectTrue(CountRecordsInPackage("TEST_DB") == 1); //  1 root object
 
     Issue("Loading just created database produces different"
         @ "`LocalDatabaseInstance` object.");
-    TEST_ExpectTrue(__().db.LoadLocal(P("TEST_DB")) == db);
+    TEST_ExpectTrue(__core().db.LoadLocal(P("TEST_DB")) == db);
     //  This set of tests fills our test database with objects
     SubTest_WritingSuccess(db);
     SubTest_WritingDataCheck(db);
@@ -495,33 +511,33 @@ protected static function Test_Writing()
         @ "local database.");
     __().memory.Free(db);   //  For `NewLocal()` call
     __().memory.Free(db);   //  For `LoadLocal()` call
-    TEST_ExpectTrue(__().db.DeleteLocal(P("TEST_DB")));
+    TEST_ExpectTrue(__core().db.DeleteLocal(P("TEST_DB")));
 
     Issue("Newly created database is reported to still exist after deletion.");
-    TEST_ExpectFalse(__().db.ExistsLocal(P("TEST_DB")));
+    TEST_ExpectFalse(__core().db.ExistsLocal(P("TEST_DB")));
     TEST_ExpectFalse(db.IsAllocated());
 
     Issue("`DeleteLocal()` does not return `false` after trying to delete"
         @ "non-existing local database.");
-    TEST_ExpectFalse(__().db.DeleteLocal(P("TEST_DB")));
+    TEST_ExpectFalse(__core().db.DeleteLocal(P("TEST_DB")));
 }
 
 protected static function Test_Recreate()
 {
     local LocalDatabaseInstance db;
     Issue("Freshly created database is not empty.");
-    db = __().db.NewLocal(P("TEST_DB"));
+    db = __core().db.NewLocal(P("TEST_DB"));
     TEST_ExpectTrue(CountRecordsInPackage("TEST_DB") == 1);
 
     Issue("Cannot create a database after database with the same name was"
         @ "just deleted.");
     TEST_ExpectNotNone(db);
-    TEST_ExpectTrue(__().db.ExistsLocal(P("TEST_DB")));
+    TEST_ExpectTrue(__core().db.ExistsLocal(P("TEST_DB")));
     SubTest_WritingArrayIndicies(db);
-    __().db.DeleteLocal(P("TEST_DB"));
+    __core().db.DeleteLocal(P("TEST_DB"));
     Issue("Newly created database is reported to still exist after deletion.");
     __().memory.Free(db);
-    TEST_ExpectFalse(__().db.ExistsLocal(P("TEST_DB")));
+    TEST_ExpectFalse(__core().db.ExistsLocal(P("TEST_DB")));
     TEST_ExpectFalse(db.IsAllocated());
 }
 
@@ -530,15 +546,15 @@ protected static function Test_TaskChaining()
     local LocalDatabaseInstance db;
     Context("Testing (re-)creating and writing into a new local database.");
     Issue("Freshly created database is not empty.");
-    db = __().db.NewLocal(P("TEST_DB"));
+    db = __core().db.NewLocal(P("TEST_DB"));
     TEST_ExpectTrue(CountRecordsInPackage("TEST_DB") == 1);
 
     Issue("Cannot create a database after database with the same name was"
         @ "just deleted.");
     TEST_ExpectNotNone(db);
-    TEST_ExpectTrue(__().db.ExistsLocal(P("TEST_DB")));
+    TEST_ExpectTrue(__core().db.ExistsLocal(P("TEST_DB")));
     SubTest_TaskChaining(db);
-    __().db.DeleteLocal(P("TEST_DB"));
+    __core().db.DeleteLocal(P("TEST_DB"));
 }
 
 protected static function HashTable GetJSONSubTemplateObject()
@@ -776,7 +792,7 @@ protected static function Test_Removal()
     local HashTable             templateObject;
     templateObject = GetJSONSubTemplateObject();
     templateArray = GetJSONSubTemplateArray();
-    db = __().db.NewLocal(P("TEST_DB"));
+    db = __core().db.NewLocal(P("TEST_DB"));
     db.WriteData(__().json.Pointer(P("")), templateObject);
     db.WriteData(__().json.Pointer(P("/B")), templateObject);
     db.WriteData(__().json.Pointer(P("/B/A")), templateArray);
@@ -787,7 +803,7 @@ protected static function Test_Removal()
     SubTest_RemovalResult(db);
     SubTest_RemovalCheckValuesAfter(db);
     SubTest_RemovalRoot(db);
-    __().db.DeleteLocal(P("TEST_DB"));
+    __core().db.DeleteLocal(P("TEST_DB"));
 }
 
 protected static function SubTest_RemovalResult(LocalDatabaseInstance db)
@@ -861,7 +877,7 @@ protected static function Test_Increment()
     local HashTable             templateObject;
     templateObject = GetJSONSubTemplateObject();
     templateArray = GetJSONSubTemplateArray();
-    db = __().db.NewLocal(P("TEST_DB"));
+    db = __core().db.NewLocal(P("TEST_DB"));
     db.WriteData(__().json.Pointer(P("")), templateObject);
     db.WriteData(__().json.Pointer(P("/B")), templateObject);
     db.WriteData(__().json.Pointer(P("/C")), __().box.int(-5));
@@ -904,7 +920,7 @@ protected static function Test_Increment()
     Issue("Incrementing database values has created garbage objects.");
     //  5 initial records + 1 made for a new array in `SubTest_IncrementNull()`
     TEST_ExpectTrue(CountRecordsInPackage("TEST_DB") == 6);
-    __().db.DeleteLocal(P("TEST_DB"));
+    __core().db.DeleteLocal(P("TEST_DB"));
 }
 
 protected static function SubTest_IncrementNull(LocalDatabaseInstance db)
@@ -1232,8 +1248,9 @@ protected static function SubTest_IncrementRewriteArray(
 
 protected static function SubTest_IncrementMissing(LocalDatabaseInstance db)
 {
-    local DBIncrementTask task;
-    Issue("New values are created in database after incrementing with path"
+    local DBIncrementTask   task;
+    local DBCheckTask       checkTask;
+    Issue("New values are not created in database after incrementing with path"
         @ "pointing to non-existing value.");
     task = db.IncrementData(__().json.Pointer(P("/L")), __().box.int(345));
     task.connect = DBIncrementHandler;
@@ -1245,13 +1262,168 @@ protected static function SubTest_IncrementMissing(LocalDatabaseInstance db)
     task.connect = DBIncrementHandler;
     task.TryCompleting();
     TEST_ExpectTrue(default.resultType == DBR_Success);
-    db.CheckDataType(__().json.Pointer(P("/L"))).connect = DBCheckHandler;
+    checkTask = db.CheckDataType(__().json.Pointer(P("/L")));
+    checkTask.connect = DBCheckHandler;
+    checkTask.TryCompleting();
+    TEST_ExpectTrue(default.resultDataType == JSON_Number);
+    TEST_ExpectTrue(default.resultType == DBR_Success);
     ReadFromDB(db, "/B/A/1/");
     TEST_ExpectTrue(default.resultDataType == JSON_Number);
     TEST_ExpectTrue(ArrayList(default.resultObject).GetLength() == 12);
     TEST_ExpectTrue(ArrayList(default.resultObject).GetInt(11) == 85);
 }
 
+protected static function Test_RequestID()
+{
+    local LocalDatabaseInstance db;
+    local ArrayList             templateArray;
+    local HashTable             templateObject;
+    templateObject = GetJSONSubTemplateObject();
+    templateArray = GetJSONSubTemplateArray();
+    db = __core().db.NewLocal(P("TEST_DB"));
+    db.WriteData(__().json.Pointer(P("")), templateObject);
+    db.WriteData(__().json.Pointer(P("/B")), templateObject);
+    db.WriteData(__().json.Pointer(P("/C")), __().box.int(-5));
+    db.WriteData(__().json.Pointer(P("/D")), __().box.bool(false));
+    db.WriteData(__().json.Pointer(P("/B/A")), templateArray);
+    db.WriteData(__().json.Pointer(P("/B/A/1")), templateObject);
+    db.WriteData(__().json.Pointer(P("/B/A/1/")), templateArray);
+    /* `db` now contains:
+    {
+        "A": "simpleValue",
+        "B": {
+            "A": [true, {
+                "A": "simpleValue",
+                "B": 11.12,
+                "": [true, null, "huh"]
+            }, "huh"],
+            "B": 11.12
+        },
+        "C": -5,
+        "D": false
+    }
+    */
+    //      Constantly recreating `db` takes time, so we make test dependent
+    //  on each other.
+    //      Generally speaking this is not great, but we cannot run them in
+    //  parallel anyway.
+    Context("Testing whether database operations report correct request ID.");
+    SubTest_RequestIDForCheck(db);
+    SubTest_RequestIDForIncrement(db);
+    SubTest_RequestIDForKeys(db);
+    SubTest_RequestIDForRead(db);
+    SubTest_RequestIDForRemove(db);
+    SubTest_RequestIDForSize(db);
+    SubTest_RequestIDForWrite(db);
+    __core().db.DeleteLocal(P("TEST_DB"));
+}
+
+protected static function SubTest_RequestIDForCheck(LocalDatabaseInstance db)
+{
+    local DBCheckTask task;
+
+    Issue("Type checking operation isn't returning correct request ID.");
+        task = db.CheckDataType(__().json.Pointer(P("/L")));
+    task.connect = DBCheckHandler;
+    task.TryCompleting();
+    TEST_ExpectTrue(default.resultRequestID == 0);
+    task = db.CheckDataType(__().json.Pointer(P("/L")), 29);
+    task.connect = DBCheckHandler;
+    task.TryCompleting();
+    TEST_ExpectTrue(default.resultRequestID == 29);
+}
+
+protected static function SubTest_RequestIDForIncrement(
+    LocalDatabaseInstance db)
+{
+    local DBIncrementTask task;
+
+    Issue("Increment operation isn't returning correct request ID.");
+    task = db.IncrementData(__().json.Pointer(P("/L")), __().box.int(29));
+    task.connect = DBIncrementHandler;
+    task.TryCompleting();
+    TEST_ExpectTrue(default.resultRequestID == 0);
+    task = db.IncrementData(__().json.Pointer(P("/L")), __().box.int(29), -7);
+    task.connect = DBIncrementHandler;
+    task.TryCompleting();
+    TEST_ExpectTrue(default.resultRequestID == -7);
+}
+
+protected static function SubTest_RequestIDForKeys(LocalDatabaseInstance db)
+{
+    local DBKeysTask task;
+
+    Issue("Keys list operation isn't returning correct request ID.");
+    task = db.GetDataKeys(__().json.Pointer(P("")));
+    task.connect = DBKeysHandler;
+    task.TryCompleting();
+    TEST_ExpectTrue(default.resultRequestID == 0);
+    task = db.GetDataKeys(__().json.Pointer(P("")), 11);
+    task.connect = DBKeysHandler;
+    task.TryCompleting();
+    TEST_ExpectTrue(default.resultRequestID == 11);
+}
+
+protected static function SubTest_RequestIDForRead(LocalDatabaseInstance db)
+{
+    local DBReadTask task;
+
+    Issue("Reading operation isn't returning correct request ID.");
+    task = db.ReadData(__().json.Pointer(P("/L")),);
+    task.connect = DBReadingHandler;
+    task.TryCompleting();
+    TEST_ExpectTrue(default.resultRequestID == 0);
+    task = db.ReadData(__().json.Pointer(P("/L")),, 666);
+    task.connect = DBReadingHandler;
+    task.TryCompleting();
+    TEST_ExpectTrue(default.resultRequestID == 666);
+}
+
+protected static function SubTest_RequestIDForRemove(LocalDatabaseInstance db)
+{
+    local DBRemoveTask task;
+
+    Issue("Removing operation isn't returning correct request ID.");
+    task = db.RemoveData(__().json.Pointer(P("/L")));
+    task.connect = DBRemoveHandler;
+    task.TryCompleting();
+    TEST_ExpectTrue(default.resultRequestID == 0);
+    task = db.RemoveData(__().json.Pointer(P("/L")), 80);
+    task.connect = DBRemoveHandler;
+    task.TryCompleting();
+    TEST_ExpectTrue(default.resultRequestID == 80);
+}
+
+protected static function SubTest_RequestIDForSize(LocalDatabaseInstance db)
+{
+    local DBSizeTask task;
+
+    Issue("Size getting operation isn't returning correct request ID.");
+    task = db.GetDataSize(__().json.Pointer(P("/L")));
+    task.connect = DBSizeHandler;
+    task.TryCompleting();
+    TEST_ExpectTrue(default.resultRequestID == 0);
+    task = db.GetDataSize(__().json.Pointer(P("/L")), 7);
+    task.connect = DBSizeHandler;
+    task.TryCompleting();
+    TEST_ExpectTrue(default.resultRequestID == 7);
+}
+
+protected static function SubTest_RequestIDForWrite(LocalDatabaseInstance db)
+{
+    local DBWriteTask task;
+
+    Issue("Writing operation isn't returning correct request ID.");
+    task = db.WriteData(__().json.Pointer(P("/L")), none);
+    task.connect = DBWritingHandler;
+    task.TryCompleting();
+    TEST_ExpectTrue(default.resultRequestID == 0);
+    task = db.WriteData(__().json.Pointer(P("/L")), none, 42);
+    task.connect = DBWritingHandler;
+    task.TryCompleting();
+    TEST_ExpectTrue(default.resultRequestID == 42);
+}
+
 defaultproperties
 {
     caseGroup   = "Database"