Publishing source maps for @tailwindcss/upgrade

[bennycode]

I tried to upgrade from Tailwind v3 to v4 using @tailwindcss/upgrade. Unfortunately, the plugin crashes with the following error:

│ Migrating templates…

TypeError: Cannot read properties of undefined (reading 'flatMap')
at ca (file:///home/bennycode/.npm/_npx/0044b4041b3b52e1/node_modules/@tailwindcss/upgrade/dist/index.mjs:229:5661)

Since the package comes without source maps (https://www.npmjs.com/package/@tailwindcss/upgrade?activeTab=code), it is really hard to tell which line makes it crash.

The only usage of flatMap that I can see is here:

• https://github.com/tailwindlabs/tailwindcss/blob/v4.1.4/packages/%40tailwindcss-upgrade/src/utils/renderer.ts#L47

@RobinMalfait, @thecrypticace, @philipp-spiess: Is it possible to provide source maps?

Best,
Benny

[phoerious]

Same here. This is the (reformatted) part where the error occurs:

a.size > 0 && I("Migrating templates\u2026");
for (let o of a.values()) {
    let u = new Set;
    for (let f of o.globs.flatMap(p => ln(p))) {
        let p = await sn([f.pattern], {absolute: !0, gitignore: !0, cwd: f.base});
        for (let d of p) u.add(d)
    }
    let c = Array.from(u);
    c.sort(), await Promise.allSettled(c.map(f => Jr(o.designSystem, o.userConfig, f))), V(`Migrated templates for configuration file: ${v(_(o.configFilePath, e))}`, {prefix: "\u21B3 "})
}

Unfortunately, I cannot really make out what this is supposed to do, since I cannot find any documentation about what these "templates" are or do.

The code crashes, because a.size is 1 and a.values() contains an object with a single key designSystem, but a[0].designSystem.globs is undefined. When I comment the template migration loop, the code runs fine.