🪟 Fix plugin loading on Windows

.changeset/sixty-peas-do.md

@@ -0,0 +1,6 @@
+---
+"myst-cli": patch
+"mystmd": patch
+---
+
+Fix imports of plugins on Windows

packages/myst-cli/src/plugins.ts

@@ -1,4 +1,5 @@
 import fs from 'node:fs';
+import { pathToFileURL } from 'node:url';
 import type { ISession } from './session/types.js';
 import { selectors } from './store/index.js';
 import { RuleId, plural, type MystPlugin, type ValidatedMystPlugin } from 'myst-common';
@@ -97,8 +98,9 @@ export async function loadPlugins(session: ISession): Promise<ValidatedMystPlugi
             return null;
           }
           let module: any;
+          const pathURL = pathToFileURL(path);
           try {
-            module = await import(path);
+            module = await import(pathURL.toString());
           } catch (error) {
             session.log.debug(`\n\n${(error as Error)?.stack}\n\n`);
             addWarningForFile(session, path, `Error reading plugin: ${error}`, 'error', {

packages/mystmd/tests/basic-plugin/index.md

@@ -0,0 +1,7 @@
+---
+title: Basic Test
+---
+
+# Lorem Ipsum
+
+Set {red}`this text` to a class of red.

packages/mystmd/tests/basic-plugin/myst.yml

@@ -0,0 +1,24 @@
+# See docs at: https://mystmd.org/guide/frontmatter
+version: 1
+project:
+  id: 22c218e1-66c6-428f-9df9-a7f2c6a3bd76
+  # title:
+  # description:
+  keywords: []
+  authors: []
+  github: https://github.com/jupyter-book/mystmd
+  # bibliography: []
+  #
+  plugins:
+    - plugin.mjs
+site:
+  template: ../templates/site/myst/book-theme
+  # title:
+  # options:
+  #   favicon: favicon.ico
+  #   logo: site_logo.png
+  nav: []
+  actions:
+    - title: Learn More
+      url: https://mystmd.org/guide
+  domains: []

packages/mystmd/tests/basic-plugin/plugin.mjs

@@ -0,0 +1,19 @@
+const redRole = {
+  name: 'red',
+  doc: 'An example role that sets a custom class.',
+  body: {
+    type: 'myst',
+    required: true,
+  },
+  run(data) {
+    const children = data.body;
+    children.forEach((child) => {
+      child.class = child.class ? `${child.class} red` : 'red';
+    });
+    return children;
+  },
+};
+
+const plugin = { name: 'Example role', roles: [redRole] };
+
+export default plugin;

packages/mystmd/tests/exports.yml

@@ -190,6 +190,13 @@ cases:
         content: outputs/basic-site-config.json
       - path: basic-site/_build/site/myst.xref.json
         content: outputs/basic-site-myst.xref.json
+  - title: Basic plugin build
+    cwd: basic-plugin
+    command: myst build
+    outputs:
+      - path: basic-plugin/_build/site/content/index.json
+        # Keys and file hashes are removed from this output file
+        content: outputs/basic-plugin-content.json
   - title: XRef site build
     cwd: site-xrefs
     command: myst build

packages/mystmd/tests/outputs/basic-plugin-content.json

@@ -0,0 +1,127 @@
+{
+  "kind": "Article",
+  "sha256": "900eec73ecdfd1641367698dab8e7727ce2a81122ba0cd641c61c4f0f3b30694",
+  "slug": "index",
+  "location": "/index.md",
+  "dependencies": [],
+  "frontmatter": {
+    "title": "Basic Test",
+    "github": "https://github.com/jupyter-book/mystmd",
+    "keywords": [],
+    "exports": [
+      {
+        "format": "md",
+        "filename": "index.md",
+        "url": "/index-827a0078d531c946c69925141436e783.md"
+      }
+    ]
+  },
+  "mdast": {
+    "type": "root",
+    "children": [
+      {
+        "type": "block",
+        "children": [
+          {
+            "type": "heading",
+            "depth": 2,
+            "position": {
+              "start": {
+                "line": 5,
+                "column": 1
+              },
+              "end": {
+                "line": 5,
+                "column": 1
+              }
+            },
+            "children": [
+              {
+                "type": "text",
+                "value": "Lorem Ipsum",
+                "position": {
+                  "start": {
+                    "line": 5,
+                    "column": 1
+                  },
+                  "end": {
+                    "line": 5,
+                    "column": 1
+                  }
+                }
+              }
+            ],
+            "identifier": "lorem-ipsum",
+            "label": "Lorem Ipsum",
+            "html_id": "lorem-ipsum",
+            "implicit": true
+          },
+          {
+            "type": "paragraph",
+            "position": {
+              "start": {
+                "line": 7,
+                "column": 1
+              },
+              "end": {
+                "line": 7,
+                "column": 1
+              }
+            },
+            "children": [
+              {
+                "type": "text",
+                "value": "Set ",
+                "position": {
+                  "start": {
+                    "line": 7,
+                    "column": 1
+                  },
+                  "end": {
+                    "line": 7,
+                    "column": 1
+                  }
+                }
+              },
+              {
+                "type": "text",
+                "value": "this text",
+                "position": {
+                  "start": {
+                    "line": 7,
+                    "column": 1
+                  },
+                  "end": {
+                    "line": 7,
+                    "column": 1
+                  }
+                },
+                "class": "red"
+              },
+              {
+                "type": "text",
+                "value": " to a class of red.",
+                "position": {
+                  "start": {
+                    "line": 7,
+                    "column": 1
+                  },
+                  "end": {
+                    "line": 7,
+                    "column": 1
+                  }
+                }
+              }
+            ]
+          }
+        ]
+      }
+    ]
+  },
+  "references": {
+    "cite": {
+      "order": [],
+      "data": {}
+    }
+  }
+}