eclipse-theia/theia

Lazily Create Monaco Models in Resource Preference Providers

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#7,426 opened on Mar 26, 2020

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 (4 comments) (0 reactions) (0 assignees)TypeScript (18,676 stars) (2,478 forks)batch import
enhancementhelp wantedmonacopreferences

Description

For a while now, AbstractResourcePreferenceProvider has used monaco editor models to manage the contents of settings files. This creates a circular dependency, because the editor model waits for preferences to be ready and preferences can't be read before the editor model is created. While this seems to work, I think it would be better if we would apply the following changes:

  1. Read the file contents directly from the file initially. Only signal "ready" once the file contents have been read
  2. Create a monaco model on demand, that is when opening an editor or when setting a preference programatically. Once we have the model, we can keep it just like now.

Opening an editor will create a model, which will wait for preferences to be ready. I also would setting a preference before the preferences provider is ready to be a programming error to be rejected.

Contributor guide

Tech stack
typescript
Domain
backend
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
TypeScriptMonaco editorTheia preference system
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
35
Research direction
Begin by examining the AbstractResourcePreferenceProvider class in the Theia codebase to understand how Monaco editor models are currently created and the circular dependency with preferences. Then, implement the two suggested changes: read file contents directly initially and only create a Monaco model on demand when an editor is opened or a preference is set programmatically. Ensure that opening an editor creates a model that waits for preferences to be ready, and that setting a preference before the provider is ready is treated as an error.