Guess extensions on extension not provided

src/deno_dir.rs

@@ -133,19 +133,41 @@ impl DenoDir {
     self: &DenoDir,
     module_name: &str,
     filename: &str,
-  ) -> DenoResult<String> {
-    if is_remote(module_name) {
-      self.fetch_remote_source(module_name, filename)
-    } else if module_name.starts_with(ASSET_PREFIX) {
+  ) -> DenoResult<CodeFetchOutput> {
+    if module_name.starts_with(ASSET_PREFIX) {
       panic!("Asset resolution should be done in JS, not Rust.");
-    } else {
-      assert_eq!(
-        module_name, filename,
-        "if a module isn't remote, it should have the same filename"
-      );
-      let src = fs::read_to_string(Path::new(filename))?;
-      Ok(src)
     }
+    let is_module_remote = is_remote(module_name);
+    let try_extension = |ext| {
+      let module_name = format!("{}{}", module_name, ext);
+      let filename = format!("{}{}", filename, ext);
+      let source_code = if is_module_remote {
+        self.fetch_remote_source(&module_name, &filename)?
+      } else {
+        assert_eq!(
+          module_name, filename,
+          "if a module isn't remote, it should have the same filename"
+        );
+        fs::read_to_string(Path::new(&filename))?
+      };
+      return Ok(CodeFetchOutput {
+        module_name: module_name.to_string(),
+        filename: filename.to_string(),
+        source_code,
+        maybe_output_code: None,
+      });
+    };
+    // Has extension, no guessing required
+    if module_name.ends_with(".ts") || module_name.ends_with(".js") {
+      return try_extension("");
+    }
+    debug!("Trying {}.ts...", module_name);
+    let ts_attempt = try_extension(".ts");
+    if let Ok(_) = ts_attempt {
+      return ts_attempt;
+    }
+    debug!("Trying {}.js...", module_name);
+    try_extension(".js")
   }
 
   pub fn code_fetch(
@@ -161,16 +183,7 @@ impl DenoDir {
     let (module_name, filename) =
       self.resolve_module(module_specifier, containing_file)?;
 
-    let result = self
-      .get_source_code(module_name.as_str(), filename.as_str())
-      .and_then(|source_code| {
-        Ok(CodeFetchOutput {
-          module_name,
-          filename,
-          source_code,
-          maybe_output_code: None,
-        })
-      });
+    let result = self.get_source_code(module_name.as_str(), filename.as_str());
     let out = match result {
       Err(err) => {
         if err.kind() == ErrorKind::NotFound {
@@ -420,6 +433,46 @@ fn test_code_fetch() {
   //println!("code_fetch_output {:?}", code_fetch_output);
 }
 
+#[test]
+fn test_code_fetch_no_ext() {
+  let (_temp_dir, deno_dir) = test_setup();
+
+  let cwd = std::env::current_dir().unwrap();
+  let cwd_string = String::from(cwd.to_str().unwrap()) + "/";
+
+  // Assuming cwd is the deno repo root.
+  let module_specifier = "./js/main";
+  let containing_file = cwd_string.as_str();
+  let r = deno_dir.code_fetch(module_specifier, containing_file);
+  assert!(r.is_ok());
+
+  // Test .ts extension
+  // Assuming cwd is the deno repo root.
+  let module_specifier = "./js/main";
+  let containing_file = cwd_string.as_str();
+  let r = deno_dir.code_fetch(module_specifier, containing_file);
+  assert!(r.is_ok());
+  let code_fetch_output = r.unwrap();
+  // could only test .ends_with to avoid include local abs path
+  assert!(code_fetch_output.module_name.ends_with("/js/main.ts"));
+  assert!(code_fetch_output.source_code.len() > 10);
+
+  // Test .js extension
+  // Assuming cwd is the deno repo root.
+  let module_specifier = "./js/mock_builtin";
+  let containing_file = cwd_string.as_str();
+  let r = deno_dir.code_fetch(module_specifier, containing_file);
+  assert!(r.is_ok());
+  let code_fetch_output = r.unwrap();
+  // could only test .ends_with to avoid include local abs path
+  assert!(
+    code_fetch_output
+      .module_name
+      .ends_with("/js/mock_builtin.js")
+  );
+  assert!(code_fetch_output.source_code.len() > 10);
+}
+
 #[test]
 fn test_src_file_to_url_1() {
   let (_temp_dir, deno_dir) = test_setup();

src/http.rs

@@ -1,15 +1,17 @@
 // Copyright 2018 the Deno authors. All rights reserved. MIT license.
 
-use errors::DenoResult;
+use errors::{DenoError, DenoResult};
+use futures::stream::Concat2;
+use futures::{Async, Future};
 use tokio_util;
 
-use futures::Future;
 use futures::Stream;
 use hyper;
 use hyper::client::Client;
 use hyper::client::HttpConnector;
 use hyper::Uri;
 use hyper_rustls;
+use std::io;
 
 type Connector = hyper_rustls::HttpsConnector<HttpConnector>;
 
@@ -26,16 +28,51 @@ pub fn get_client() -> Client<Connector, hyper::Body> {
   Client::builder().build(c)
 }
 
+struct FetchedBodyFuture {
+  body: Concat2<hyper::Body>,
+  status: hyper::StatusCode,
+}
+
+struct FetchedBody {
+  body: hyper::Chunk,
+  status: hyper::StatusCode,
+}
+
+impl Future for FetchedBodyFuture {
+  type Item = FetchedBody;
+  type Error = hyper::Error;
+  fn poll(&mut self) -> Result<Async<FetchedBody>, hyper::Error> {
+    match self.body.poll()? {
+      Async::Ready(body) => Ok(Async::Ready(FetchedBody {
+        body,
+        status: self.status.clone(),
+      })),
+      Async::NotReady => Ok(Async::NotReady),
+    }
+  }
+}
+
 // The CodeFetch message is used to load HTTP javascript resources and expects a
 // synchronous response, this utility method supports that.
 pub fn fetch_sync_string(module_name: &str) -> DenoResult<String> {
   let url = module_name.parse::<Uri>().unwrap();
   let client = get_client();
-  let future = client
-    .get(url)
-    .and_then(|response| response.into_body().concat2());
-  let body = tokio_util::block_on(future)?;
-  Ok(String::from_utf8(body.to_vec()).unwrap())
+  let fetch_future = client.get(url).and_then(|response| {
+    let status = response.status();
+    FetchedBodyFuture {
+      body: response.into_body().concat2(),
+      status,
+    }
+  });
+
+  let fetch_result = tokio_util::block_on(fetch_future)?;
+  if !fetch_result.status.is_success() {
+    return Err(DenoError::from(io::Error::new(
+      io::ErrorKind::NotFound,
+      format!("cannot load from '{}'", module_name),
+    )));
+  }
+  Ok(String::from_utf8(fetch_result.body.to_vec()).unwrap())
 }
 
 /* TODO(ry) Re-enabled this test. Disabling to work around bug in #782.

tests/015_import_no_ext.ts

@@ -0,0 +1,10 @@
+import { isTSFile, printHello, phNoExt } from "./subdir/mod3";
+console.log(isTSFile);
+console.log(printHello);
+console.log(phNoExt);
+
+import { isMod4 } from "./subdir/mod4";
+console.log(isMod4);
+
+import { printHello as ph } from "http://localhost:4545/tests/subdir/mod2";
+console.log(ph);

tests/015_import_no_ext.ts.out

@@ -0,0 +1,7 @@
+Downloading http://localhost:4545/tests/subdir/mod2.ts
+Downloading http://localhost:4545/tests/subdir/print_hello.ts
+true
+[Function: printHello]
+[Function: printHello]
+true
+[Function: printHello]

tests/error_006_import_ext_failure.ts

@@ -0,0 +1 @@
+import "./non-existent";

tests/error_006_import_ext_failure.ts.out

@@ -0,0 +1,11 @@
+NotFound: Cannot resolve module "./non-existent" from "[WILDCARD]deno/tests/error_006_import_ext_failure.ts"
+    at maybeError (deno/js/errors.ts:[WILDCARD])
+    at maybeThrowError (deno/js/errors.ts:[WILDCARD])
+    at sendSync (deno/js/dispatch.ts:[WILDCARD])
+    at Object.codeFetch (deno/js/os.ts:[WILDCARD])
+    at DenoCompiler.resolveModule (deno/js/compiler.ts:[WILDCARD])
+    at DenoCompiler._resolveModuleName (deno/js/compiler.ts:[WILDCARD])
+    at moduleNames.map.name (deno/js/compiler.ts:[WILDCARD])
+    at Array.map (<anonymous>)
+    at DenoCompiler.resolveModuleNames (deno/js/compiler.ts:[WILDCARD])
+    at Object.compilerHost.resolveModuleNames (deno/third_party/node_modules/typescript/lib/typescript.js:[WILDCARD])

tests/subdir/mod3.js

@@ -0,0 +1 @@
+export const isTSFile = false;

tests/subdir/mod3.ts

@@ -0,0 +1,3 @@
+export const isTSFile = true;
+export { printHello } from "./print_hello.ts";
+export { printHello as phNoExt } from "./print_hello";

tests/subdir/mod4.js

@@ -0,0 +1 @@
+export const isMod4 = true;