fix: throw precise, actionable error on unusable deno cli

```
Error: There was a problem setting up the Edge Functions environment. To try a manual installation,
visit https://ntl.fyi/install-deno.
```

This happens _a lot_:
https://github.com/netlify/cli/issues?q=is%3Aissue%20%22There%20was%20a%20problem%20setting%20up%20the%20Edge%20Functions%20environment%22.

It means we failed to download, install, or execute a local deno binary, or we're trying to use one
that doesn't behave as expected or match the expected version range.

This error message is imprecise and not very actionable.

This commit bubbles the previously swallowed error details, adds more info, and adds a recommended
step that [has been found to unblock
users](netlify/cli#7700 (comment)) and which I've personally
used to unblock myself.

Author: serhalp

packages/edge-bundler/node/bridge.test.ts

@@ -136,3 +136,57 @@ test('Does inherit environment variables if `extendEnv` is not set', async () =>
 
   await rm(tmpDir.path, { force: true, recursive: true, maxRetries: 10 })
 })
+
+test('Provides detailed error message when downloaded binary cannot be executed', async () => {
+  const tmpDir = await tmp.dir()
+  const latestVersion = semver.minVersion(DENO_VERSION_RANGE)?.version ?? ''
+  const data = new PassThrough()
+  const archive = archiver('zip', { zlib: { level: 9 } })
+
+  archive.pipe(data)
+  // Create a binary that will fail to execute (invalid content)
+  archive.append(Buffer.from('invalid binary content'), {
+    name: platform === 'win32' ? 'deno.exe' : 'deno',
+  })
+  archive.finalize()
+
+  const target = getPlatformTarget()
+
+  nock('https://dl.deno.land').get('/release-latest.txt').reply(200, `v${latestVersion}`)
+  nock('https://dl.deno.land')
+    .get(`/release/v${latestVersion}/deno-${target}.zip`)
+    .reply(200, () => data)
+
+  const deno = new DenoBridge({
+    cacheDirectory: tmpDir.path,
+    useGlobal: false,
+  })
+
+  try {
+    await deno.getBinaryPath()
+    expect.fail('Should have thrown an error')
+  } catch (error) {
+    expect(error).toBeInstanceOf(Error)
+    const errorMessage = (error as Error).message
+
+    // Verify the error message structure and required information
+    expect(errorMessage).toContain('Failed to set up Deno for Edge Functions')
+
+    // Verify actual error is included (should be ENOEXEC, EACCES, or similar)
+    expect(errorMessage).toMatch(/Error: .+/)
+
+    // Verify binary path is shown with actual path (not just the label)
+    expect(errorMessage).toMatch(/Downloaded to: .+\/deno(\.exe)?/)
+    expect(errorMessage).toContain(tmpDir.path)
+
+    // Verify platform info is shown with actual values (not just the label)
+    expect(errorMessage).toMatch(/Platform: (darwin|linux|win32)\/(x64|arm64|ia32)/)
+
+    // Verify actionable guidance is provided
+    expect(errorMessage).toContain('This may be caused by permissions, antivirus software, or platform incompatibility')
+    expect(errorMessage).toContain('Try clearing the Deno cache and retrying')
+    expect(errorMessage).toContain('https://ntl.fyi/install-deno')
+  }
+
+  await rm(tmpDir.path, { force: true, recursive: true, maxRetries: 10 })
+})

packages/edge-bundler/node/bridge.ts

@@ -82,14 +82,23 @@ export class DenoBridge {
     this.logger.system(`Downloading Deno CLI to ${this.cacheDirectory}`)
 
     const binaryPath = await download(this.cacheDirectory, this.versionRange, this.logger)
-    const downloadedVersion = await this.getBinaryVersion(binaryPath)
+    const result = await this.getBinaryVersion(binaryPath)
 
-    // We should never get here, because it means that `DENO_VERSION_RANGE` is
-    // a malformed semver range. If this does happen, let's throw an error so
-    // that the tests catch it.
-    if (downloadedVersion === undefined) {
+    // If we can't execute the downloaded binary, provide detailed error information
+    // to help users diagnose the issue (permissions, platform incompatibility, etc.)
+    if (result.error) {
       const error = new Error(
-        'There was a problem setting up the Edge Functions environment. To try a manual installation, visit https://ntl.fyi/install-deno.',
+        `Failed to set up Deno for Edge Functions.
+Error: ${result.error.message}
+Downloaded to: ${binaryPath}
+Platform: ${process.platform}/${process.arch}
+
+This may be caused by permissions, antivirus software, or platform incompatibility.
+
+Try clearing the Deno cache and retrying:
+  ${this.cacheDirectory}
+
+To install Deno manually: https://ntl.fyi/install-deno`,
       )
 
       await this.onAfterDownload?.(error)
@@ -99,26 +108,29 @@ export class DenoBridge {
       throw error
     }
 
-    await this.writeVersionFile(downloadedVersion)
+    await this.writeVersionFile(result.version)
 
     await this.onAfterDownload?.()
 
     return binaryPath
   }
 
-  async getBinaryVersion(binaryPath: string) {
+  async getBinaryVersion(
+    binaryPath: string,
+  ): Promise<{ version: string; error?: undefined } | { version?: undefined; error: Error }> {
     try {
       const { stdout } = await execa(binaryPath, ['--version'])
       const version = stdout.match(/^deno ([\d.]+)/)
 
       if (!version) {
         this.logger.system(`getBinaryVersion no version found. binaryPath ${binaryPath}`)
-        return
+        return { error: new Error('Could not parse Deno version from output') }
       }
 
-      return version[1]
+      return { version: version[1] }
     } catch (error) {
       this.logger.system('getBinaryVersion failed', error)
+      return { error: error instanceof Error ? error : new Error(String(error)) }
     }
   }
 
@@ -150,11 +162,11 @@ export class DenoBridge {
     }
 
     const globalBinaryName = 'deno'
-    const globalVersion = await this.getBinaryVersion(globalBinaryName)
+    const result = await this.getBinaryVersion(globalBinaryName)
 
-    if (globalVersion === undefined || !semver.satisfies(globalVersion, this.versionRange)) {
+    if (result.error || !semver.satisfies(result.version, this.versionRange)) {
       this.logger.system(
-        `No globalVersion or semver not satisfied. globalVersion: ${globalVersion}, versionRange: ${this.versionRange}`,
+        `No globalVersion or semver not satisfied. globalVersion: ${result.version}, versionRange: ${this.versionRange}`,
       )
       return
     }

packages/edge-bundler/node/config.ts

@@ -97,7 +97,8 @@ export const getFunctionConfig = async ({
   const collector = await tmp.file()
 
   // Retrieving the version of Deno.
-  const version = new SemVer((await deno.getBinaryVersion((await deno.getBinaryPath({ silent: true })).path)) || '')
+  const result = await deno.getBinaryVersion((await deno.getBinaryPath({ silent: true })).path)
+  const version = new SemVer(result.version || '')
 
   // The extractor will use its exit code to signal different error scenarios,
   // based on the list of exit codes we send as an argument. We then capture