Bug: Runtime crash "Variable used without being declared" in compiled mode under strict scoping (MustDeclareVars)

[Blowcake]

Hi @ioa747 and @mlipok,

i want to report a small scoping issue i encountered when testing the library (version 2.2.2-alpha) in compiled mode (@Compiled = 1) with strict variable declaration enabled (Opt("MustDeclareVars", 1)).

---

The Problem

When running a compiled binary, the global variable $_g_bNetWebView2_DebugDev is automatically set to True (via Global $_g_bNetWebView2_DebugDev = (@Compiled = 1)).

During default navigation (e.g. when $sExpectedTitle is empty ""), the function _NetWebView2_LoadWait is called.

Inside _NetWebView2_LoadWait (around lines 636~652), the code checks if the expected navigation events are reached:

ElseIf $iLastMessage >= $iWaitMessage Then ; RULE 6: checking requested events messages
    If $iWaitMessage = $NETWEBVIEW2_MESSAGE__TITLE_CHANGED And $sExpectedTitle Then ; RULE 7: checking Expected document title
        Local $sCurrentTitle = $oWebV2M.GetDocumentTitle()
        Local $bTitleCheck = (StringRegExp($sCurrentTitle, $sExpectedTitle, $STR_REGEXPMATCH) = 1)
        Local $s_DEV_Info = "! IFNC: DEV: TEST LOAD WAIT: Prefix:: " & $s_Prefix & " TitleCheck=" & $bTitleCheck & " LastMessage=" & $iLastMessage & " CurrentTitle=" & $sCurrentTitle
        If $_g_bNetWebView2_DebugDev Then ConsoleWrite($s_DEV_Info & " #SLN=" & @ScriptLineNumber & @CRLF)
        If $bTitleCheck Then
            $MSG = " TitleCheck=" & $bTitleCheck & " #SLN=" & @ScriptLineNumber
            $RET = True
            ExitLoop
        EndIf
    Else
        If $_g_bNetWebView2_DebugDev Then ConsoleWrite($s_DEV_Info & " #SLN=" & @ScriptLineNumber & @CRLF)
        $MSG = " LastMessage=" & $iLastMessage & " #SLN=" & @ScriptLineNumber
        $RET = True
        ExitLoop
    EndIf

Because $sExpectedTitle is empty, the If block is skipped, and execution goes to the Else block.
However, in the Else block, the code tries to reference $s_DEV_Info:

If $_g_bNetWebView2_DebugDev Then ConsoleWrite($s_DEV_Info & " #SLN=" & @ScriptLineNumber & @CRLF)

Since $s_DEV_Info is declared with Local inside the If block, it is never declared or initialized at runtime when entering the Else block. Because $_g_bNetWebView2_DebugDev is True when compiled, AutoIt evaluates this line and crashes immediately with:

Error: Variable used without being declared.

(Note: The issue doesn't show up in uncompiled mode because $_g_bNetWebView2_DebugDev is False, which skips the ConsoleWrite call at runtime).

---

Proposed Fix

We can easily fix this by changing the Else block's ConsoleWrite to not reference the undeclared $s_DEV_Info (or by declaring it outside the If/Else blocks).

For example, using an inline string in the Else block:

 	Else
-		If $_g_bNetWebView2_DebugDev Then ConsoleWrite($s_DEV_Info & " #SLN=" & @ScriptLineNumber & @CRLF)
+		If $_g_bNetWebView2_DebugDev Then ConsoleWrite("! IFNC: DEV: TEST LOAD WAIT: Prefix:: " & $s_Prefix & " LastMessage=" & $iLastMessage & " #SLN=" & @ScriptLineNumber & @CRLF)
 		$MSG = " LastMessage=" & $iLastMessage & " #SLN=" & @ScriptLineNumber
 		$RET = True
 		ExitLoop
 	EndIf

Thank you again for maintaining this library, and let me know if you need any further testing/feedback on this or the throttling changes!

Best regards
Harald Frank

[ioa747]

Hi @Blowcake and @mlipok,

Thank you @Blowcake for the excellent code review and the detailed bug report!
You are 100% correct about the strict scoping issue under @Compiled = 1 with MustDeclareVars.

To fix this properly, instead of duplicating the string inline inside the Else block, we can declare $s_DEV_Info right where Rule 6 begins.
This ensures the variable is safely registered in the scope for both the If and Else branches.

Furthermore, while refactoring this loop, I noticed another performance bottleneck: the loop was hitting _NetWebView2_ExecuteScript for document.readyState every 10ms continuously while the page was still loading.
This creates unnecessary COM overhead.

To solve both issues, I refactored the function to:
Fix the scope crash by moving $s_DEV_Info higher up.

Introduce an adaptive throttling mechanism:
while readyState is not "complete", it enters an Else block with an additional __NetWebView2_Sleep(50) to let the browser breathe, reducing COM spamming by over 80%.
Once it becomes "complete", it drops back to the fast 10ms polling to capture final events instantly.

Here is the fully revised _NetWebView2_LoadWait function for review:

Func _NetWebView2_LoadWait($oWebV2M, $iWaitMessage = $NETWEBVIEW2_MESSAGE__TITLE_CHANGED, $sExpectedTitle = "", $iTimeOut_ms = 5000)
    Local Const $s_Prefix = "[_NetWebView2_LoadWait]: WaitMessage:" & $iWaitMessage & " ExpectedTitle:" & (($sExpectedTitle) ? ($sExpectedTitle) : ("[is EMPTY]")) & " TimeOut_ms:" & $iTimeOut_ms
    Local $ERR = 0, $EXT = 0, $RET = False, $MSG = "" ; predefined endpoint results
    Local $hTimer = TimerInit()

    ; RESET: Clear the status of this instance before starting the wait loop
    __NetWebView2_LastMessage_Navigation($oWebV2M, $NETWEBVIEW2_MESSAGE__NONE)

    While 1
        __NetWebView2_Sleep(10) ; Allow AutoIt to "breathe" and process the GUI messages, also allow user to abort
        If @error Then
            $ERR = @error
            $EXT = @extended
            $RET = False
            ExitLoop
        EndIf

        Local $bWebIsReady = $oWebV2M.IsReady ; RULE 1: Check if browser IsReady
        If @error Then ; browser/COM error ?
            $ERR = 1
            $RET = False
            ExitLoop
        ElseIf $iTimeOut_ms And TimerDiff($hTimer) >= $iTimeOut_ms Then ; RULE 2: TimeOut Check
            __NetWebView2_Log(@ScriptLineNumber, $s_Prefix & " - TIME OUT - the waiting time has expired", 1, $ERR, $EXT)
            $ERR = 2
            $RET = False
            ExitLoop
        ElseIf Not $bWebIsReady Then ; RULE 3: if browser is not ready continue waiting
            ContinueLoop ; For navigation events, ensure the browser reports IsReady
        EndIf

        ; RULE 4: checking browser DOM ReadyState
        Local $iLastMessage = -1
        Local $sReadyState = _NetWebView2_ExecuteScript($oWebV2M, "document.readyState", $NETWEBVIEW2_EXECUTEJS_MODE2_RESULT)
        If @error Then ; RULE 4: checking ready state - DOM should not fire event
            $ERR = 3
            $RET = False
            $MSG = " document.readyState execution Error" & " #SLN=" & @ScriptLineNumber
            ExitLoop
        ElseIf StringLeft($sReadyState, 6) == "ERROR:" Then ; RULE 4: checking ready state JavaScript result on case of error
            $ERR = 4
            $RET = False
            $MSG = " document.readyState execution Error" & " #SLN=" & @ScriptLineNumber
            ExitLoop
        ElseIf $sReadyState = "complete" Then ; RULE 4: checking browser DOM ReadyState is "complete"
            $iLastMessage = __NetWebView2_LastMessage_Navigation($oWebV2M)
            If $_g_bNetWebView2_DebugDev Then ConsoleWrite("! IFNC: DEV: TEST LOAD WAIT: ReadyState=" & $sReadyState & " LastMessage=" & $iLastMessage & " WaitMessage=" & $iWaitMessage & " #SLN=" & @ScriptLineNumber & @CRLF)
            If $iLastMessage = $NETWEBVIEW2_MESSAGE__NAV_ERROR Or $iLastMessage = $NETWEBVIEW2_MESSAGE__PROCESS_FAILED Or $iLastMessage = $NETWEBVIEW2_MESSAGE__CRITICAL_ERROR Then ; RULE 5: messages of specific Error occurs
                If $_g_bNetWebView2_DebugDev Then ConsoleWrite("! IFNC: DEV: TEST LOAD WAIT:" & $iLastMessage & " #SLN=" & @ScriptLineNumber & @CRLF)
                $ERR = 5
                $RET = False
                ExitLoop
            ElseIf $iLastMessage >= $iWaitMessage Then ; RULE 6: checking requested events messages
                ; 🚧 Fixed Harald's Scope Bug - Declared here so it's safely accessible by both If and Else blocks
                Local $s_DEV_Info = "! IFNC: DEV: TEST LOAD WAIT: Prefix:: " & $s_Prefix & " LastMessage=" & $iLastMessage

                If $iWaitMessage = $NETWEBVIEW2_MESSAGE__TITLE_CHANGED And $sExpectedTitle Then ; RULE 7: checking Expected document title - only if $NETWEBVIEW2_MESSAGE__TITLE_CHANGED was choosed
                    Local $sCurrentTitle = $oWebV2M.GetDocumentTitle()
                    Local $bTitleCheck = (StringRegExp($sCurrentTitle, $sExpectedTitle, $STR_REGEXPMATCH) = 1)
                    $s_DEV_Info &= " TitleCheck=" & $bTitleCheck & " CurrentTitle=" & $sCurrentTitle
                    If $_g_bNetWebView2_DebugDev Then ConsoleWrite($s_DEV_Info & " #SLN=" & @ScriptLineNumber & @CRLF)
                    If $bTitleCheck Then
                        $MSG = " TitleCheck=" & $bTitleCheck & " #SLN=" & @ScriptLineNumber
                        $RET = True
                        ExitLoop
                    EndIf
                Else
                    If $_g_bNetWebView2_DebugDev Then ConsoleWrite($s_DEV_Info & " #SLN=" & @ScriptLineNumber & @CRLF)
                    $MSG = " LastMessage=" & $iLastMessage & " #SLN=" & @ScriptLineNumber
                    $RET = True
                    ExitLoop
                EndIf
            EndIf
        Else
            ; 🚧 If state is "loading" or "interactive", sleep 50ms before hitting COM/JS again to reduce CPU load
            __NetWebView2_Sleep(50)
        EndIf
        If $_g_bNetWebView2_DebugDev Then ConsoleWrite("! IFNC: DEV: TEST LOAD WAIT: __NetWebView2_LastMessage_Navigation($oWebV2M)=" & $iLastMessage & " >> " & __NetWebView2_LastMessage_Navigation($oWebV2M) & " #SLN=" & @ScriptLineNumber & @CRLF)
    WEnd

    __NetWebView2_Log(@ScriptLineNumber, $s_Prefix & $MSG, 1, $ERR, $EXT)
    Return SetError($ERR, $EXT, $RET)
EndFunc   ;==>_NetWebView2_LoadWait

[Blowcake]

Hi ioa747,

that reads to me as a robust and excellent solution. As soon a new test version is out, ill try to test this and give you a quick feedback .o)

Best Regards
Harald Frank