Bun --watch flag issue

[jtenner]

Hey! Thank you for this amazing software.

The only issue I had was an issue with bun when using the --watch flag.

When the compilation of a given module fails with a syntax error, it prevents the plugin from generating any more modules. This breaks the --watch flag features.

Instead of failing, it makes sense to catch the error, log it to stderr, and then use a previously cached version of that module.

Features added:

• Bugfix: Prevent plugin from crashing
• Bugfix: Report errors to console for end users

A few questions:

1. Is there a specific coding style I should conform to? Or is this solution fine?
2. How can we "test" this, or should we just accept that it can't be tested well?

To try it out locally:

1. Install Bun
2. Initialize a bun project bun init -y
3. Add bunfig.toml with preload = ["./dist/bun-civet.mjs"]
4. Create index.civet with Bun.write "./test.txt", "Hello world!"
5. bun --watch index.civet
6. Add a syntax error (like a bunch of ='s) and change the "Hello world!" string to something else
7. Notice that ./text.txt remains unmodified
8. Remove the syntax errors from index.civet
9. Check ./text.txt for the corresponding changes

I'm very happy to help or make modifications.

[edemaine]

I'm worried about this change, because it would cause bun foo.civet to merely display an error, but not give an exit code, when foo.civet has a parse error. I'm trying to figure out whether there's a better approach, though Bun's onLoad doesn't seem to have a way to return an error other than throwing one... Possibly this is just a bug in bun --watch.

[edemaine]

Suggested change

	const cache = new Map<string, string>
	cache := new Map<string, string>

[edemaine]

I've reported as oven-sh/bun#17270 — we'll see what the Bun folks think about it.

[uinz]

oven-sh/bun#4689 (comment)

try this

# bunfig.toml
preload = ["./plugin.ts"]

// plugin.ts
import { compile } from "@danielx/civet";
import { plugin } from "bun";

await plugin({
  name: "Civet loader",
  async setup(builder) {
    builder.onLoad({ filter: /\.civet$/ }, async ({ path }) => {
-     const source = await file(path).text();
+     const { default: source } = await import(`${path}?`, { with: { type: "text" } });

      const contents = await compile(source);

      return {
        contents,
        loader: "tsx",
      };
    });
  },
});

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oven-sh/bun#10983 (comment)

Although the above method can temporarily solve the bun bug, bun has another bug. Calling process.exit() in watch mode will exit the watch process.