Guess extensions on extension not provided (#859)

Fixes #857

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 use_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,
+      });
+    };
+    let default_attempt = use_extension("");
+    if default_attempt.is_ok() {
+      return default_attempt;
+    }
+    debug!("Trying {}.ts...", module_name);
+    let ts_attempt = use_extension(".ts");
+    if ts_attempt.is_ok() {
+      return ts_attempt;
+    }
+    debug!("Trying {}.js...", module_name);
+    use_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 +433,48 @@ 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.filename.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.filename.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

@@ -1,10 +1,12 @@
 // Copyright 2018 the Deno authors. All rights reserved. MIT license.
 
-use errors::DenoResult;
+use errors;
+use errors::{DenoError, DenoResult};
 use tokio_util;
 
-use futures::Future;
-use futures::Stream;
+use futures;
+use futures::future::Either;
+use futures::{Future, Stream};
 use hyper;
 use hyper::client::Client;
 use hyper::client::HttpConnector;
@@ -31,11 +33,25 @@ pub fn get_client() -> Client<Connector, hyper::Body> {
 pub fn fetch_sync_string(module_name: &str) -> DenoResult<String> {
   let url = module_name.parse::<Uri>().unwrap();
   let client = get_client();
-  let future = client
+  let fetch_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())
+    .map_err(|err| DenoError::from(err))
+    .and_then(|response| {
+      if !response.status().is_success() {
+        return Either::A(futures::future::err(errors::new(
+          errors::ErrorKind::NotFound,
+          "module not found".to_string(),
+        )));
+      }
+      Either::B(
+        response
+          .into_body()
+          .concat2()
+          .map(|body| String::from_utf8(body.to_vec()).unwrap())
+          .map_err(|err| DenoError::from(err)),
+      )
+    });
+  tokio_util::block_on(fetch_future)
 }
 
 /* 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 +1,8 @@
+Downloading http://localhost:4545/tests/subdir/mod2
+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;