add hoistStaticGlobParts

This is an implementation similar to what we already have in Rust. The
idea is that we want to move the static parts to the `base` path. This
allows us to use `..` in the pattern and the glob would be adjusted
correctly.

Without this, globby will error if your pattern escapes the base path by
using `..` in the pattern.

packages/@tailwindcss-upgrade/src/index.ts

@@ -21,6 +21,7 @@ import { migrate as migrateTemplate } from './template/migrate'
 import { prepareConfig } from './template/prepare-config'
 import { args, type Arg } from './utils/args'
 import { isRepoDirty } from './utils/git'
+import { hoistStaticGlobParts } from './utils/hoist-static-glob-parts'
 import { pkg } from './utils/packages'
 import { eprintln, error, header, highlight, info, success } from './utils/renderer'
 
@@ -143,11 +144,11 @@ async function run() {
       info('Migrating templates using the provided configuration file.')
       for (let config of configBySheet.values()) {
         let set = new Set<string>()
-        for (let { pattern, base } of config.globs) {
-          let files = await globby([pattern], {
+        for (let globEntry of config.globs.flatMap((entry) => hoistStaticGlobParts(entry))) {
+          let files = await globby([globEntry.pattern], {
             absolute: true,
             gitignore: true,
-            cwd: base,
+            cwd: globEntry.base,
           })
 
           for (let file of files) {

packages/@tailwindcss-upgrade/src/utils/hoist-static-glob-parts.test.ts

@@ -0,0 +1,48 @@
+import { expect, it } from 'vitest'
+import { hoistStaticGlobParts } from './hoist-static-glob-parts'
+
+it.each([
+  // A basic glob
+  [
+    { base: '/projects/project-a', pattern: './src/**/*.html' },
+    [{ base: '/projects/project-a/src', pattern: '**/*.html' }],
+  ],
+
+  // A glob pointing to a folder should result in `**/*`
+  [
+    { base: '/projects/project-a', pattern: './src' },
+    [{ base: '/projects/project-a/src', pattern: '**/*' }],
+  ],
+
+  // A glob pointing to a file, should result in the file as the pattern
+  [
+    { base: '/projects/project-a', pattern: './src/index.html' },
+    [{ base: '/projects/project-a/src', pattern: 'index.html' }],
+  ],
+
+  // A glob going up a directory, should result in the new directory as the base
+  [
+    { base: '/projects/project-a', pattern: '../project-b/src/**/*.html' },
+    [{ base: '/projects/project-b/src', pattern: '**/*.html' }],
+  ],
+
+  // A glob with curlies, should be expanded to multiple globs
+  [
+    { base: '/projects/project-a', pattern: '../project-{b,c}/src/**/*.html' },
+    [
+      { base: '/projects/project-b/src', pattern: '**/*.html' },
+      { base: '/projects/project-c/src', pattern: '**/*.html' },
+    ],
+  ],
+  [
+    { base: '/projects/project-a', pattern: '../project-{b,c}/src/**/*.{js,html}' },
+    [
+      { base: '/projects/project-b/src', pattern: '**/*.js' },
+      { base: '/projects/project-b/src', pattern: '**/*.html' },
+      { base: '/projects/project-c/src', pattern: '**/*.js' },
+      { base: '/projects/project-c/src', pattern: '**/*.html' },
+    ],
+  ],
+])('should hoist the static parts of the glob: %s', (input, output) => {
+  expect(hoistStaticGlobParts(input)).toEqual(output)
+})

packages/@tailwindcss-upgrade/src/utils/hoist-static-glob-parts.ts

@@ -0,0 +1,78 @@
+import braces from 'braces'
+import path from 'node:path'
+
+interface GlobEntry {
+  base: string
+  pattern: string
+}
+
+export function hoistStaticGlobParts(entry: GlobEntry): GlobEntry[] {
+  return braces(entry.pattern, { expand: true }).map((pattern) => {
+    let clone = { ...entry }
+    let [staticPart, dynamicPart] = splitPattern(pattern)
+
+    // Move static part into the `base`.
+    if (staticPart !== null) {
+      clone.base = path.resolve(entry.base, staticPart)
+    } else {
+      clone.base = path.resolve(entry.base)
+    }
+
+    // Move dynamic part into the `pattern`.
+    if (dynamicPart === null) {
+      clone.pattern = '**/*'
+    } else {
+      clone.pattern = dynamicPart
+    }
+
+    // If the pattern looks like a file, move the file name from the `base` to
+    // the `pattern`.
+    let file = path.basename(clone.base)
+    if (file.includes('.')) {
+      clone.pattern = file
+      clone.base = path.dirname(clone.base)
+    }
+
+    return clone
+  })
+}
+
+// Split a glob pattern into a `static` and `dynamic` part.
+//
+// Assumption: we assume that all globs are expanded, which means that the only
+// dynamic parts are using `*`.
+//
+// E.g.:
+//  Original input: `../project-b/**/*.{html,js}`
+//  Expanded input: `../project-b/**/*.html` & `../project-b/**/*.js`
+//  Split on first input: ("../project-b", "**/*.html")
+//  Split on second input: ("../project-b", "**/*.js")
+function splitPattern(pattern: string): [staticPart: string | null, dynamicPart: string | null] {
+  // No dynamic parts, so we can just return the input as-is.
+  if (!pattern.includes('*')) {
+    return [pattern, null]
+  }
+
+  let lastSlashPosition: number | null = null
+
+  for (let [i, c] of pattern.split('').entries()) {
+    if (c === '/') {
+      lastSlashPosition = i
+    }
+
+    if (c === '*' || c === '!') {
+      break
+    }
+  }
+
+  // Very first character is a `*`, therefore there is no static part, only a
+  // dynamic part.
+  if (lastSlashPosition === null) {
+    return [null, pattern]
+  }
+
+  let staticPart = pattern.slice(0, lastSlashPosition).trim()
+  let dynamicPart = pattern.slice(lastSlashPosition + 1).trim()
+
+  return [staticPart || null, dynamicPart || null]
+}