This commit adds an unstable lint plugin API.
Plugins are specified in the `deno.json` file under
`lint.plugins` option like so:
```
{
"lint": {
"plugins": [
"./plugins/my-plugin.ts",
"jsr:@deno/lint-plugin1",
"npm:@deno/lint-plugin2"
]
}
}
```
The API is considered unstable and might be subject
to changes in the future.
Plugin API was modelled after ESLint API for the
most part, but there are no guarantees for compatibility.
The AST format exposed to plugins is closely modelled
after the AST that `typescript-eslint` uses.
Lint plugins use the visitor pattern and can add
diagnostics like so:
```
export default {
name: "lint-plugin",
rules: {
"plugin-rule": {
create(context) {
return {
Identifier(node) {
if (node.name === "a") {
context.report({
node,
message: "should be b",
fix(fixer) {
return fixer.replaceText(node, "_b");
},
});
}
},
};
},
},
},
} satisfies Deno.lint.Plugin;
```
Besides reporting errors (diagnostics) plugins can provide
automatic fixes that use text replacement to apply changes.
---------
Co-authored-by: Marvin Hagemeister <marvin@deno.com>
Co-authored-by: David Sherret <dsherret@gmail.com>
This PR changes the underlying buffer backed AST format we use for
JavaScript-based linting plugins. It adds support for various new types,
makes traversal code a lot easier and is more polished compared to
previous iterations.
Here is a quick summary (in no particular order):
- Node prop data is separate from traversal, which makes traversal code
so much easier to reason about. Previously, it was interleaved with node
prop data
- spans are in a separate table as well, as they are rarely needed.
- schema is separate from SWC conversion logic, which makes
- supports recursive plain objects
- supports numbers
- supports bigint
- supports regex
- adds all SWC nodes
Apologies, this is kinda a big PR, but it's worth it imo.
_Marking as draft because I need to update some tests tomorrow._
When running selectors for JS linting plugins we would error when
encountering an unknown attribute name:
```js
// selector
Foo[non-existant]
// error
Error: Missing string id: <number>
```
This was caused by using `0` as the invalid marker, but also overloading
`0` with an actual node type. So the fix is to reserve `0` as the
invalid marker and move the property type to the next index.
This PR extracts the core part of
https://github.com/denoland/deno/pull/27203 to make it easier to review
and land in parts.
It contains:
- The JS plugin code the deserializes and walks the buffer
- The Rust portion to serialize SWC to the buffer format (a bunch of
nodes are still todos, but imo these can land anytime later)
- Basic lint plugin types, without the AST node types to make this PR
easier to review
- Added more code comments to explain the format etc.
More fixes and changes will be done in follow-up PRs.
---------
Co-authored-by: Bartek Iwańczuk <biwanczuk@gmail.com>
