👍 Add workaround for Deno cache issue

See #358 for more detail.

Author: lambdalisue

denops/@denops-private/service.ts

@@ -149,6 +149,24 @@ class Plugin {
       await mod.main(this.#denops);
       await emit(this.#denops, `DenopsSystemPluginPost:${this.name}`);
     } catch (e) {
+      // Show a warning message when Deno module cache issue is detected
+      // https://github.com/vim-denops/denops.vim/issues/358
+      if (
+        e instanceof TypeError &&
+        e.message.startsWith(
+          "Could not find constraint in the list of versions: ",
+        )
+      ) {
+        console.warn("*".repeat(80));
+        console.warn(`Deno module cache issue is detected.`);
+        console.warn(
+          `Execute 'call denops#cache#update(#{reload: v:true})' and restart Vim/Neovim.`,
+        );
+        console.warn(
+          `See https://github.com/vim-denops/denops.vim/issues/358 for more detail.`,
+        );
+        console.warn("*".repeat(80));
+      }
       console.error(`Failed to load plugin '${this.name}': ${e}`);
       await emit(this.#denops, `DenopsSystemPluginFail:${this.name}`);
     }

denops/@denops-private/service_test.ts

@@ -19,6 +19,9 @@ const scriptValid =
   new URL("./testdata/dummy_valid_plugin.ts", import.meta.url).href;
 const scriptInvalid =
   new URL("./testdata/dummy_invalid_plugin.ts", import.meta.url).href;
+const scriptInvalidConstraint =
+  new URL("./testdata/dummy_invalid_constraint_plugin.ts", import.meta.url)
+    .href;
 
 Deno.test("Service", async (t) => {
   const meta: Meta = {
@@ -144,6 +147,48 @@ Deno.test("Service", async (t) => {
     },
   );
 
+  await t.step(
+    "load() loads plugin and emits autocmd events (could not find constraint)",
+    async () => {
+      const c = stub(console, "warn");
+      const s = stub(host, "call");
+      try {
+        await service.load("dummyFailConstraint", scriptInvalidConstraint);
+        const expects = [
+          "********************************************************************************",
+          "Deno module cache issue is detected.",
+          "Execute 'call denops#cache#update(#{reload: v:true})' and restart Vim/Neovim.",
+          "See https://github.com/vim-denops/denops.vim/issues/358 for more detail.",
+          "********************************************************************************",
+        ];
+        assertSpyCalls(c, expects.length);
+        for (let i = 0; i < expects.length; i++) {
+          assertSpyCall(c, i, {
+            args: [expects[i]],
+          });
+        }
+        assertSpyCalls(s, 2);
+        assertSpyCall(s, 0, {
+          args: [
+            "denops#api#cmd",
+            "doautocmd <nomodeline> User DenopsSystemPluginPre:dummyFailConstraint",
+            {},
+          ],
+        });
+        assertSpyCall(s, 1, {
+          args: [
+            "denops#api#cmd",
+            "doautocmd <nomodeline> User DenopsSystemPluginFail:dummyFailConstraint",
+            {},
+          ],
+        });
+      } finally {
+        s.restore();
+        c.restore();
+      }
+    },
+  );
+
   await t.step(
     "load() does nothing when the plugin is already loaded",
     async () => {

denops/@denops-private/testdata/dummy_invalid_constraint_plugin.ts

@@ -0,0 +1,8 @@
+import type { Entrypoint } from "https://deno.land/x/denops_core@v6.1.0/mod.ts";
+
+export const main: Entrypoint = (_denops) => {
+  // Mimic the situation
+  throw new TypeError(
+    "Could not find constraint in the list of versions: @std/encoding@0.224.3",
+  );
+};