[wasm][debugger] Fixing race condition

[thaystg]

Unfortunatelly I wasn't able to reproduce it in a test case. To reproduce it using a Blazor app was also very difficult.

I created a separated buffer to receive the "pauses"(breakpoint, exception, user_break, etc.) from the debugger and another buffer to uses to the responses that we receive from debugger when we ask for some information (locals value, invoke method, object values, etc;)

Fixes https://devdiv.visualstudio.com/DevDiv/_workitems/edit/1427671
Fixes #64474

Test case to reproduce:

Change the content of FetchData.razor in a Blazor app from the template:

@page "/fetchdata"
@using BlazorApp89.Shared
@using System.Collections.ObjectModel
@inject HttpClient Http

<PageTitle>Weather forecast</PageTitle>

<h1>Weather forecast</h1>

<p>This component demonstrates fetching data from the server.</p>

@if (forecasts == null)
{
    <p><em>Loading...</em></p>
}
else
{
    <table class="table">
        <thead>
            <tr>
                <th>Date</th>
                <th>Temp. (C)</th>
                <th>Temp. (F)</th>
                <th>Summary</th>
            </tr>
        </thead>
        <tbody>
            @foreach (var forecast in forecasts)
            {
                <tr>
                    <td>@forecast.Date.ToShortDateString()</td>
                    <td>@forecast.TemperatureC</td>
                    <td>@forecast.TemperatureF</td>
                    <td>@forecast.Summary</td>
                </tr>
            }
        </tbody>
    </table>
}

@code {
    private WeatherForecast[]? forecasts;

    protected override async Task OnInitializedAsync()
    {
        forecasts = await RetForecasts();
        var otherVar = await GetObservableCollection();
        Console.WriteLine(otherVar);
    }
    protected async Task<WeatherForecast[]> RetForecasts()
    {
        var a = await Http.GetFromJsonAsync<WeatherForecast[]>("WeatherForecast");
        var b = await Http.GetFromJsonAsync<WeatherForecast[]>("WeatherForecast");
        var c = await Http.GetFromJsonAsync<WeatherForecast[]>("WeatherForecast");
        var d = await Http.GetFromJsonAsync<WeatherForecast[]>("WeatherForecast");
        var e = await Http.GetFromJsonAsync<WeatherForecast[]>("WeatherForecast");
        Console.WriteLine(b);
        Console.WriteLine(c);
        Console.WriteLine(d);
        Console.WriteLine(e);
        return a;
    }
    protected async Task<ObservableCollection<WeatherForecast>> GetObservableCollection()
    {
        var forecastsLocal = await RetForecasts();
        return new ObservableCollection<WeatherForecast>(forecastsLocal.ToList<WeatherForecast>());
    }
}

Add a breakpoint on line: 46, step into hovering the mouse over the WeatherForecast[] on RetForecasts method.

[ghost]

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Issue Details

---

Unfortunatelly I wasn't able to reproduce it in a test case. To reproduce it using a Blazor app was also very difficult.

I created a separated buffer to receive the "pauses"(breakpoint, exception, user_break, etc.) from the debugger and another buffer to uses to the responses that we receive from debugger when we ask for some information (locals value, invoke method, object values, etc;)

Fixes https://devdiv.visualstudio.com/DevDiv/_workitems/edit/1427671

Test case to reproduce:

Change the content of FetchData.razor in a Blazor app from the template:

@page "/fetchdata"
@using BlazorApp89.Shared
@using System.Collections.ObjectModel
@inject HttpClient Http

<PageTitle>Weather forecast</PageTitle>

<h1>Weather forecast</h1>

<p>This component demonstrates fetching data from the server.</p>

@if (forecasts == null)
{
    <p><em>Loading...</em></p>
}
else
{
    <table class="table">
        <thead>
            <tr>
                <th>Date</th>
                <th>Temp. (C)</th>
                <th>Temp. (F)</th>
                <th>Summary</th>
            </tr>
        </thead>
        <tbody>
            @foreach (var forecast in forecasts)
            {
                <tr>
                    <td>@forecast.Date.ToShortDateString()</td>
                    <td>@forecast.TemperatureC</td>
                    <td>@forecast.TemperatureF</td>
                    <td>@forecast.Summary</td>
                </tr>
            }
        </tbody>
    </table>
}

@code {
    private WeatherForecast[]? forecasts;

    protected override async Task OnInitializedAsync()
    {
        forecasts = await RetForecasts();
        var otherVar = await GetObservableCollection();
        Console.WriteLine(otherVar);
    }
    protected async Task<WeatherForecast[]> RetForecasts()
    {
        var a = await Http.GetFromJsonAsync<WeatherForecast[]>("WeatherForecast");
        var b = await Http.GetFromJsonAsync<WeatherForecast[]>("WeatherForecast");
        var c = await Http.GetFromJsonAsync<WeatherForecast[]>("WeatherForecast");
        var d = await Http.GetFromJsonAsync<WeatherForecast[]>("WeatherForecast");
        var e = await Http.GetFromJsonAsync<WeatherForecast[]>("WeatherForecast");
        Console.WriteLine(b);
        Console.WriteLine(c);
        Console.WriteLine(d);
        Console.WriteLine(e);
        return a;
    }
    protected async Task<ObservableCollection<WeatherForecast>> GetObservableCollection()
    {
        var forecastsLocal = await RetForecasts();
        return new ObservableCollection<WeatherForecast>(forecastsLocal.ToList<WeatherForecast>());
    }
}

Add a breakpoint on line: 46, step into moving the mouse over the WeatherForecast[] on RetForecasts method.

Author:	thaystg
Assignees:	-
Labels:	area-Debugger-mono
Milestone:	-

[lewing]

should we make the

[radical]

Can we rename this to GetNewId?

[radical]

Check if there is an existing entry for id.

[thaystg]

And if there is, should I print a warning?

[radical]

cmdId == 0 is a special one now. Can you add a comment for that here?

[lewing]

One small comment but looks good

[lewing]

I'd suggest making a method that combines get and delete

[lewing]

👍