Fix rebuilds when editing imported CSS files

CHANGELOG.md

@@ -21,6 +21,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Use the right import base path when using the CLI to reading files from stdin ([#14522](https://github.com/tailwindlabs/tailwindcss/pull/14522))
 - Ensure that `@utility` is top-level and cannot be nested ([#14525](https://github.com/tailwindlabs/tailwindcss/pull/14525))
+- Editing imported CSS files should trigger a rebuild ([#14561](https://github.com/tailwindlabs/tailwindcss/pull/14561))
 - _Experimental_: Improve codemod output, keep CSS after last Tailwind directive unlayered ([#14512](https://github.com/tailwindlabs/tailwindcss/pull/14512))
 - _Experimental_: Fix incorrect empty `layer()` at the end of `@import` at-rules when running codemods ([#14513](https://github.com/tailwindlabs/tailwindcss/pull/14513))
 - _Experimental_: Do not wrap comment nodes in `@layer` when running codemods ([#14517](https://github.com/tailwindlabs/tailwindcss/pull/14517))

integrations/cli/index.test.ts

@@ -112,7 +112,7 @@ describe.each([
         `,
         'project-a/index.html': html`
           <div
-            class="underline 2xl:font-bold hocus:underline inverted:flex"
+            class="underline 2xl:font-bold hocus:underline inverted:flex text-primary"
           ></div>
         `,
         'project-a/plugin.js': js`
@@ -128,10 +128,17 @@ describe.each([
         `,
         'project-a/src/index.css': css`
           @import 'tailwindcss/utilities';
+          @import './custom-theme.css';
           @config '../tailwind.config.js';
           @source '../../project-b/src/**/*.html';
           @plugin '../plugin.js';
         `,
+        'project-a/src/custom-theme.css': css`
+          /* Will be overwritten later */
+          @theme {
+            --color-primary: black;
+          }
+        `,
         'project-a/src/index.js': js`
           const className = "content-['project-a/src/index.js']"
           module.exports = { className }
@@ -157,6 +164,11 @@ describe.each([
         candidate`content-['project-b/src/index.js']`,
         candidate`inverted:flex`,
         candidate`hocus:underline`,
+        css`
+          .text-primary {
+            color: var(--color-primary, black);
+          }
+        `,
       ])
 
       await fs.write(
@@ -180,6 +192,24 @@ describe.each([
       await fs.expectFileToContain('project-a/dist/out.css', [
         candidate`[.changed_&]:content-['project-b/src/index.js']`,
       ])
+
+      await fs.write(
+        'project-a/src/custom-theme.css',
+        css`
+          /* Overriding the primary color */
+          @theme {
+            --color-primary: red;
+          }
+        `,
+      )
+
+      await fs.expectFileToContain('project-a/dist/out.css', [
+        css`
+          .text-primary {
+            color: var(--color-primary, red);
+          }
+        `,
+      ])
     },
   )
 

integrations/postcss/index.test.ts

@@ -342,7 +342,7 @@ test(
       `,
       'project-a/index.html': html`
         <div
-          class="underline 2xl:font-bold hocus:underline inverted:flex"
+          class="underline 2xl:font-bold hocus:underline inverted:flex text-primary"
         ></div>
       `,
       'project-a/plugin.js': js`
@@ -358,10 +358,17 @@ test(
       `,
       'project-a/src/index.css': css`
         @import 'tailwindcss/utilities';
+        @import './custom-theme.css';
         @config '../tailwind.config.js';
         @source '../../project-b/src/**/*.html';
         @plugin '../plugin.js';
       `,
+      'project-a/src/custom-theme.css': css`
+        /* Will be overwritten later */
+        @theme {
+          --color-primary: black;
+        }
+      `,
       'project-a/src/index.js': js`
         const className = "content-['a/src/index.js']"
         module.exports = { className }
@@ -389,6 +396,11 @@ test(
       candidate`content-['b/src/index.js']`,
       candidate`inverted:flex`,
       candidate`hocus:underline`,
+      css`
+        .text-primary {
+          color: var(--color-primary, black);
+        }
+      `,
     ])
 
     await fs.write(
@@ -414,5 +426,23 @@ test(
     await fs.expectFileToContain('project-a/dist/out.css', [
       candidate`[.changed_&]:content-['project-b/src/index.js']`,
     ])
+
+    await fs.write(
+      'project-a/src/custom-theme.css',
+      css`
+        /* Overriding the primary color */
+        @theme {
+          --color-primary: red;
+        }
+      `,
+    )
+
+    await fs.expectFileToContain('project-a/dist/out.css', [
+      css`
+        .text-primary {
+          color: var(--color-primary, red);
+        }
+      `,
+    ])
   },
 )

integrations/vite/index.test.ts

@@ -287,7 +287,7 @@ for (let transformer of ['postcss', 'lightningcss']) {
               <link rel="stylesheet" href="./src/index.css" />
             </head>
             <body>
-              <div class="underline">Hello, world!</div>
+              <div class="underline text-primary">Hello, world!</div>
             </body>
           `,
           'project-a/tailwind.config.js': js`
@@ -298,9 +298,16 @@ for (let transformer of ['postcss', 'lightningcss']) {
           'project-a/src/index.css': css`
             @import 'tailwindcss/theme' theme(reference);
             @import 'tailwindcss/utilities';
+            @import './custom-theme.css';
             @config '../tailwind.config.js';
             @source '../../project-b/src/**/*.html';
           `,
+          'project-a/src/custom-theme.css': css`
+            /* Will be overwritten later */
+            @theme {
+              --color-primary: black;
+            }
+          `,
           'project-b/src/index.html': html`
             <div class="flex" />
           `,
@@ -322,7 +329,37 @@ for (let transformer of ['postcss', 'lightningcss']) {
           filename = files[0][0]
         })
 
-        await fs.expectFileToContain(filename, [candidate`underline`, candidate`flex`])
+        await fs.expectFileToContain(filename, [
+          candidate`underline`,
+          candidate`flex`,
+          css`
+            .text-primary {
+              color: var(--color-primary, black);
+            }
+          `,
+        ])
+
+        await retryAssertion(async () => {
+          await fs.write(
+            'project-a/src/custom-theme.css',
+            css`
+              /* Overriding the primary color */
+              @theme {
+                --color-primary: red;
+              }
+            `,
+          )
+
+          let files = await fs.glob('project-a/dist/**/*.css')
+          expect(files).toHaveLength(1)
+          let [, styles] = files[0]
+
+          expect(styles).toContain(css`
+            .text-primary {
+              color: var(--color-primary, red);
+            }
+          `)
+        })
 
         await retryAssertion(async () => {
           // Updates are additive and cause new candidates to be added.

packages/@tailwindcss-node/src/compile.ts

@@ -74,6 +74,8 @@ async function loadStylesheet(id: string, base: string, onDependency: (path: str
   let resolvedPath = await resolveCssId(id, base)
   if (!resolvedPath) throw new Error(`Could not resolve '${id}' from '${base}'`)
 
+  onDependency(resolvedPath)
+
   if (typeof globalThis.__tw_readFile === 'function') {
     let file = await globalThis.__tw_readFile(resolvedPath, 'utf-8')
     if (file) {