Implement workflow versioning and keep the existing instance upon import

[hyzx86]

Is your feature request related to a problem? Please describe.

At present, the imported workflow type always cleans up the workflow instances of the process.

In some cases, we want to keep them, otherwise the process in progress will be cleaned up.

Describe the solution you'd like

There was a note in the source code before, which gave the scheme. We should implement the workflow version.

Describe alternatives you've considered

No

[sebastienros]

I assume this is cleaned up because the instances might be in a state that is incompatible with the new definition? Can you link to the code that is doing it?

An option could be to have a flag in the workflow definition step to not clean the instances.

[hyzx86]

Yes, here , at line 77.

OrchardCore/src/OrchardCore.Modules/OrchardCore.Workflows/Recipes/WorkflowTypeStep.cs

Lines 49 to 80 in 7d83e81

	var model = context.Step.ToObject<WorkflowStepModel>();
	var urlHelper = GetUrlHelper();
	foreach (var token in model.Data.Cast<JsonObject>())
	{
	var workflow = token.ToObject<WorkflowType>(_jsonSerializerOptions);
	var existing = await _workflowTypeStore.GetAsync(workflow.WorkflowTypeId);
	if (existing is null)
	{
	workflow.Id = 0;
	if (urlHelper is not null)
	{
	foreach (var activity in workflow.Activities.Where(a => a.Name == nameof(HttpRequestEvent)))
	{
	if (!activity.Properties.TryGetPropertyValue("TokenLifeSpan", out var tokenLifeSpan))
	{
	continue;
	}
	activity.Properties["Url"] = ReGenerateHttpRequestEventUrl(urlHelper, workflow, activity, tokenLifeSpan.ToObject<int>());
	}
	}
	}
	else
	{
	await _workflowTypeStore.DeleteAsync(existing);
	}
	await _workflowTypeStore.SaveAsync(workflow);

[hyzx86]

And here

OrchardCore/src/OrchardCore.Modules/OrchardCore.Workflows/Services/WorkflowTypeStore.cs

Lines 71 to 84 in 7d83e81

	public async Task DeleteAsync(WorkflowType workflowType)
	{
	// Delete workflows first.
	var workflows = await _session.Query<Workflow, WorkflowIndex>(x => x.WorkflowTypeId == workflowType.WorkflowTypeId).ListAsync();
	foreach (var workflow in workflows)
	{
	_session.Delete(workflow);
	}
	// Then delete the workflow type.
	_session.Delete(workflowType);
	var context = new WorkflowTypeDeletedContext(workflowType);
	await _handlers.InvokeAsync((handler, context) => handler.DeletedAsync(context), context, _logger);