add test case

cli/js/compiler.ts

@@ -595,6 +595,11 @@ function buildSourceFileCache(
     for (const importDesc of entry.imports) {
       let mappedUrl = importDesc.resolvedSpecifier;
       const importedFile = sourceFileMap[importDesc.resolvedSpecifier];
+      // IMPORTANT: due to HTTP redirects we might end up in situation
+      // where URL points to a file with completely different URL.
+      // In that case we take value of `redirect` field and cache
+      // resolved specifier pointing to the value of the redirect.
+      // It's not very elegant solution and should be rethinked.
       assert(importedFile);
       if (importedFile.redirect) {
         mappedUrl = importedFile.redirect;

cli/module_graph.rs

@@ -135,7 +135,8 @@ impl ModuleGraphLoader {
     self.download_module(specifier.clone(), None)?;
 
     loop {
-      let (specifier, source_file) = self.pending_downloads.next().await.unwrap()?;
+      let (specifier, source_file) =
+        self.pending_downloads.next().await.unwrap()?;
       self.visit_module(&specifier, source_file)?;
       if self.pending_downloads.is_empty() {
         break;
@@ -354,8 +355,12 @@ impl ModuleGraphLoader {
     let mut type_headers = vec![];
 
     // IMPORTANT: source_file.url might be different than requested
-    // module_specifier - this situation needs to be handled manually
-    if module_specifier.to_string() != source_file.url.to_string() {
+    // module_specifier because of HTTP redirects. In such
+    // situation we add an "empty" ModuleGraphFile with 'redirect'
+    // field set that will be later used in TS worker when building
+    // map of available source file. It will perform substitution
+    // for proper URL point to redirect target.
+    if module_specifier != source_file.url.to_string() {
       // TODO(bartlomieju): refactor, this is a band-aid
       self.graph.0.insert(
         module_specifier.to_string(),
@@ -373,7 +378,7 @@ impl ModuleGraphLoader {
           type_headers: vec![],
         },
       );
-    } 
+    }
 
     let module_specifier = ModuleSpecifier::from(source_file.url.clone());
     let source_code = String::from_utf8(source_file.source_code)?;

cli/tests/integration_tests.rs

@@ -1565,6 +1565,13 @@ itest!(type_directives_js_main {
   exit_code: 0,
 });
 
+itest!(type_directives_redirect {
+  args:
+    "run --reload http://localhost:4545/cli/tests/type_directives_redirect.js",
+  output: "type_directives_redirect.ts.out",
+  http_server: true,
+});
+
 itest!(types {
   args: "types",
   output: "types.out",

tools/http_server.py

@@ -122,6 +122,34 @@ def do_GET(self):
             self.wfile.write(bytes("export const foo = 'foo';"))
             return
 
+        if "type_directives_redirect.js" in self.path:
+            self.protocol_version = "HTTP/1.1"
+            self.send_response(200, 'OK')
+            self.send_header('Content-type', 'application/javascript')
+            self.send_header(
+                'X-TypeScript-Types',
+                'http://localhost:4547/xTypeScriptTypesRedirect.d.ts')
+            self.end_headers()
+            self.wfile.write(bytes("export const foo = 'foo';"))
+            return
+
+        if "xTypeScriptTypesRedirect.d.ts" in self.path:
+            self.protocol_version = "HTTP/1.1"
+            self.send_response(200, 'OK')
+            self.send_header('Content-type', 'application/typescript')
+            self.end_headers()
+            self.wfile.write(
+                bytes("import './xTypeScriptTypesRedirected.d.ts';"))
+            return
+
+        if "xTypeScriptTypesRedirected.d.ts" in self.path:
+            self.protocol_version = "HTTP/1.1"
+            self.send_response(200, 'OK')
+            self.send_header('Content-type', 'application/typescript')
+            self.end_headers()
+            self.wfile.write(bytes("export const foo: 'foo';"))
+            return
+
         if "xTypeScriptTypes.d.ts" in self.path:
             self.protocol_version = "HTTP/1.1"
             self.send_response(200, 'OK')