fetch detected tasks twice on clicking "Run Tasks"

[elaihau]

• detected tasks are fetched N+1 times when users click "Run Tasks" from
  the menu, where N is the number of customized detected tasks in the
  tasks.json.

• fixes "Run tasks" calls same Task Provider repeatedly. #7496

Signed-off-by: Liang Huang lhuang4@ualberta.ca

What it does

Refactored TaskConfigurations.getTasks().
Instead of fetching detected tasks from providers for every single customized detected task, only fetch from providers for the 1st customized detected task, and from the cache for the rest.

How to test

I smoke-tested the following features:

• Open Terminal -> Run Tasks, and check if the detected tasks and customzied detected tasks are properly displayed.
• Check if the detected tasks and customzied detected tasks can be started properly.
• Added logging to ProvidedTaskConfigurations.getTasks() to ensure it is called once by TaskConfigurations.getTasks(), and two times in total when Terminal -> Run Tasks is clicked.

Review checklist

• as an author, I have thoroughly tested my changes and carefully followed the review guidelines

[tsmaeder]

Unfortunately, I think the approach you've chosen is not optimal: it requires clients of "ProvidedTasksConfiguration" to manage the cases where they want to use cached tasks or refetch from the task providers. Also, while it fixes the concrete case I found, there may be other code paths that still refetch multiple times.
The question we need to ask, IMO is how long we consider the fetched tasks to be valid. During that interval we want a non-changing set of contributed tasks. My approach would add a "clearCache" call on "ProvidedTaskConfigurations" and call that whenever we need to.
The correct points to clear the cache is whenever we start a new user operation, in my opinion. So either from commands or on the level of method call on "TaskService".
I'll try to do a quick PoC.

[tsmaeder]

I sketched my approach here: #7633

[elaihau]

Unfortunately, I think the approach you've chosen is not optimal: it requires clients of "ProvidedTasksConfiguration" to manage the cases where they want to use cached tasks or refetch from the task providers. Also, while it fixes the concrete case I found, there may be other code paths that still refetch multiple times.
The question we need to ask, IMO is how long we consider the fetched tasks to be valid. During that interval we want a non-changing set of contributed tasks. My approach would add a "clearCache" call on "ProvidedTaskConfigurations" and call that whenever we need to.
The correct points to clear the cache is whenever we start a new user operation, in my opinion. So either from commands or on the level of method call on "TaskService".
I'll try to do a quick PoC.

Thank you for the POC ! I believe yours is better. I will close this one :)