[ViteJS] Empty coverage for all files not covered by tests

Versions

• What is this plugin’s version? 3.9.12
• What is Cypress version? 9.1.0
• What is your operating system? MacOS
• How do you instrument your application? Instanbul
• Is there .nyc_output folder? Yes, not empty
• Do you have any custom NYC settings? Yes, all
• Do you run Cypress tests in a Docker container? No

Describe the bug Despite using the all setting of NYC, it seems like only files touched by tests have their line numbers included in the report. The other files are present but show 0 lines thus are ignored in the final computation of the code coverage. Using the debug flag, I see them added:

  code-coverage adding empty coverage for file /Users/Sytten/Projects/*****/src/main.ts +0ms
  code-coverage adding empty coverage for file /Users/Sytten/Projects/*****/src/composables/index.ts +0ms
  code-coverage adding empty coverage for file /Users/Sytten/Projects/*****/src/composables/useId.ts +0ms
  code-coverage adding empty coverage for file /Users/Sytten/Projects/*****src/composables/useName.ts +0ms

But I would expect them to get line numbers at some point. But they only get:

TN:
SF:src/main.ts
FNF:0
FNH:0
LF:0
LH:0
BRF:0
BRH:0
end_of_record

I use ViteJS and my plugins looks like:

const path = require("path");
const { startDevServer } = require("@cypress/vite-dev-server");
const codeCoverageTask = require("@cypress/code-coverage/task");
const istanbul = require("vite-plugin-istanbul");

module.exports = (on, config) => {
  on("dev-server:start", (options) =>
    startDevServer({
      options,
      viteConfig: {
        logLevel: "warn",
        configFile: path.resolve(__dirname, "..", "..", "vite.config.js"),
        plugins: [istanbul({})],
      },
    })
  );

  codeCoverageTask(on, config);
  return config;
};

Support contains:

// Import commands.js using ES2015 syntax:
import "./commands";

// Alternatively you can use CommonJS syntax:
// require('./commands')

import "@cypress/code-coverage/support";

The coverage for files under test works fine.

Link to the repo This is not an open-source project, but happy to provide a reproduction if that can help debug it.

[lmiller1990]

Thanks for the bug report - this should be enough to reproduce and work on this issue.

[lmiller1990]

I am looking into code coverage for Vite.