This commit introduces a new feature that allows theme developers to manage the transformation of theme settings over time. Similar to Rails migrations, the theme settings migration system enables developers to write and execute migrations for theme settings, ensuring a smooth transition when changes are required in the format or structure of setting values.
Example use cases for the theme settings migration system:
1. Renaming a theme setting.
2. Changing the data type of a theme setting (e.g., transforming a string setting containing comma-separated values into a proper list setting).
3. Altering the format of data stored in a theme setting.
All of these use cases and more are now possible while preserving theme setting values for sites that have already modified their theme settings.
Usage:
1. Create a top-level directory called `migrations` in your theme/component, and then within the `migrations` directory create another directory called `settings`.
2. Inside the `migrations/settings` directory, create a JavaScript file using the format `XXXX-some-name.js`, where `XXXX` is a unique 4-digit number, and `some-name` is a descriptor of your choice that describes the migration.
3. Within the JavaScript file, define and export (as the default) a function called `migrate`. This function will receive a `Map` object and must also return a `Map` object (it's acceptable to return the same `Map` object that the function received).
4. The `Map` object received by the `migrate` function will include settings that have been overridden or changed by site administrators. Settings that have never been changed from the default will not be included.
5. The keys and values contained in the `Map` object that the `migrate` function returns will replace all the currently changed settings of the theme.
6. Migrations are executed in numerical order based on the XXXX segment in the migration filenames. For instance, `0001-some-migration.js` will be executed before `0002-another-migration.js`.
Here's a complete example migration script that renames a setting from `setting_with_old_name` to `setting_with_new_name`:
```js
// File name: 0001-rename-setting.js
export default function migrate(settings) {
if (settings.has("setting_with_old_name")) {
settings.set("setting_with_new_name", settings.get("setting_with_old_name"));
}
return settings;
}
```
Internal topic: t/109980
Why this change?
Currently, we do not have a method to easily retrieve a theme setting's
value on the server side. Such a method can be useful in the test
environment where we need to retrieve the theme's setting and use its
value in assertions.
What does this change do?
This change introduces the `Theme#get_setting` instance method.
We run the ember-this-fallback transformation on plugin and theme code so that they can continue omitting `this.` in `.hbs` templates. A bug in the implementation meant that it was incorrectly transforming things like `{{dir/some-component}}` into `<DirSomeComponent />` (rather than `<Dir::SomeComponent />`).
This commit uses patch-package to apply the fix from https://github.com/tildeio/ember-this-fallback/pull/56
Reverts e2705df and re-lands #23187 and #23219.
The issue was incorrect order of execution of Rails' `assets:precompile` task in our own precompilation stack.
Co-authored-by: David Taylor <david@taylorhq.com>
Manipulating theme module paths means that the paths you author are not the ones used at runtime. This can lead to some very unexpected behavior and potential module name clashes. It also meant that the refactor in 16c6ab8661 was unable to correctly match up theme connector js/templates.
While this could technically be a breaking change, I think it is reasonably safe because:
1. Themes are already forced to use relative paths when referencing their own modules (since they're namespaced based on the site-specific id). The only time this might be problematic is when theme tests reference modules in the theme's main `javascripts` directory
2. For things like components/services/controllers/etc. our custom Ember resolver works backwards from the end of the path, so adding `discourse/` in the middle will not affect resolution.
Previously we were discovering plugin outlets by checking first for dedicated template files, and then looking for classes to match them. This doesn't work for components which are entirely defined in JS (e.g. those authored with gjs, or those which are re-exports of a colocated component).
This commit refactors our detection logic to look for both class and template modules in a single pass. It also refactors things so that the modules themselves are required lazily when needd, rather than all being loaded during app boot.
This brings the theme development experience (via the discourse_theme cli) closer to the experience of making javascript changes in Discourse core/plugins via Ember CLI. Whenever a change is made to a non-css theme field, all clients will be instructed to immediately refresh via message-bus.
Instead of having to remember every time, just always wait until the
current transaction (if it exists) has committed before clearing any
DistributedCache.
The only exception to this is caches that aren't caching things from
postgres.
This means we have to do the test setup after setting the test
transaction, because doing the test setup involves clearing caches.
Reapplying this - it now doesn't use after_commit if skip_db is set
Instead of having to remember every time, just always wait until the
current transaction (if it exists) has committed before clearing any
DistributedCache.
The only exception to this is caches that aren't caching things from
postgres.
This means we have to do the test setup after setting the test
transaction, because doing the test setup involves clearing caches.
Our theme system injects a magical `settings` object at the top of themes JS modules to allow theme authors to access the settings as configured by admins in the UI. Within this `settings` object, there are a couple of special objects `theme_uploads` and `theme_uploads_local` that contain URLs for all the assets/uploads that the theme has.
For test modules/files, the theme system also injects a `settings` object at the top of tests modules, but it's not the same object as the object that's injected in non-test files. The difference is that in tests we want the settings to have their default values as opposed to any custom values that may exist in the site's database. This ensures that test results are consistent no matter the site that runs them.
However, the `settings` object in tests files currently doesn't have the special objects `theme_uploads` and `theme_uploads_local` which means that if a theme includes an asset that's lazy-loaded, it's not possible to write tests for anything that depends on the lazy-loaded asset because the theme will not be able to load the asset during the tests since `theme_uploads_local` and `theme_uploads` don't exist. This PR adds these special objects inside the `settings` object for test files.
Internal topic: t/71825/52.
Theme javascript is now minified using Terser, just like our core/plugin JS bundles. This reduces the amount of data sent over the network.
This commit also introduces sourcemaps for theme JS. Browser developer tools will now be able show each source file separately when browsing, and also in backtraces.
For theme test JS, the sourcemap is inlined for simplicity. Network load is not a concern for tests.
Previously, compiling theme 'extra_js' was done with a number of steps. Each theme_field would be compiled into its own value_baked column, and then the JavascriptCache content would be built by concatenating all of those compiled values.
This commit streamlines things by removing the value_baked step. The raw value of all extra_js theme_fields are passed directly to the ThemeJavascriptCompiler, and then the result is stored in the JavascriptCache.
In itself, this commit should not cause any behavior change. It is designed to open the door to more advanced compilation features which have interdependencies between different source files (e.g. template colocation, sourcemaps).
Previously we were relying on a highly-customized version of the unmaintained Barber gem for theme template compilation. This commit switches us to use our own DiscourseJsProcessor, which makes use of more modern patterns and will be easier to maintain going forward.
In summary:
- Refactors DiscourseJsProcessor to move multiline JS heredocs into a companion `discourse-js-processor.js` file
- Use MiniRacer's `.call` method to avoid manually escaping JS strings
- Move Theme template AST transformers into DiscourseJsProcessor, and formalise interface for extending RawHandlebars AST transformations
- Update Ember template compilation to use a babel-based approach, just like Ember CLI. This gives each template its own ES6 module rather than directly assigning `Ember.TEMPLATES` values
- Improve testing of template compilation (and move some tests from `theme_javascript_compiler_spec.rb` to `discourse_js_processor_spec.rb`
The source-of-truth for our ember version is now the installed node_module. The `ember_source` gem carries an old version of Ember and so the constant is no longer useful. We'll be dropping the gem soon.
This commit makes a number of improvements to the DiscourseJsProcessor:
1. Remove dependence on the out-of-date Ember template compiler from the ember-rails gem; switch to modern template compiler
2. Refactor to make use of a proper module system with `define`/`require`
3. Introduce `babel-plugin-ember-template-compilation` to enable inline hbs compilation
The `mini-loader` is upgraded to support relative lookup and `require.has`, so that these new JS packages work correctly.
Our theme system is very complex and it can take a while to figure out how to invalidate the various types of caches that are used throughout the theme system. So, having a single helper method that invalidates everything can be useful in emergency situations where there is no time to read through the code and figure out how to clear the various caches.
Internal ticket: t64732.
All `DistributedCache` instances in Discourse are automatically keyed on the `Discourse.git_version`. Normally the theme compiler version is updated via a commit, and everything is fine. However, in some situations, it's possible for the BASE_COMPILER_VERSION to change without a change to the git_version (e.g. when applying patches directly to the codebase).
This commit adds the `BASE_COMPILER_VERSION` to the DistributedCache key to ensure that content from different compiler versions does not leak into other processes.
This is pre-request work to introduce a splash screen while site assets load.
The only change this commit introduces is that it ensures we add the defer attribute to core/plugin/theme .JS files. This will allow us to insert markup before the browser starts evaluating those scripts later on. It has no visual or functional impact on core.
This will not have any impact on how themes and plugins work. The only exception is themes loading external scripts in the </head> theme field directly via script tags. Everything will work the same but those would need to add the defer attribute if they want to keep the benefits introduced in this PR.
