fix(cli): expand tsc roots when using checkJs (#15164)

A JS file can still point to a TS file, so we need to expand the roots
in the checkJs case too.

Fixes: #15163

cli/emit.rs

@@ -199,15 +199,13 @@ pub fn get_ts_config_for_emit(
 /// Transform the graph into root specifiers that we can feed `tsc`. We have to
 /// provide the media type for root modules because `tsc` does not "resolve" the
 /// media type like other modules, as well as a root specifier needs any
-/// redirects resolved. If we aren't checking JavaScript, we need to include all
+/// redirects resolved. We need to include all the emittable files in
-/// the emittable files in the roots, so they get type checked and optionally
+/// the roots, so they get type checked and optionally emitted,
-/// emitted, otherwise they would be ignored if only imported into JavaScript.
+/// otherwise they would be ignored if only imported into JavaScript.
 fn get_tsc_roots(
-  roots: &[(ModuleSpecifier, ModuleKind)],
   graph_data: &GraphData,
   check_js: bool,
 ) -> Vec<(ModuleSpecifier, MediaType)> {
-  if !check_js {
   graph_data
     .entries()
     .into_iter()
@@ -232,17 +230,6 @@ fn get_tsc_roots(
       _ => None,
     })
     .collect()
-  } else {
-    roots
-      .iter()
-      .filter_map(|(specifier, _)| match graph_data.get(specifier) {
-        Some(ModuleEntry::Module { media_type, .. }) => {
-          Some((specifier.clone(), *media_type))
-        }
-        _ => None,
-      })
-      .collect()
-  }
 }
 
 /// A hashing function that takes the source code, version and optionally a
@@ -328,7 +315,7 @@ pub fn check(
     return Ok(Default::default());
   }
 
-  let root_names = get_tsc_roots(roots, &segment_graph_data, check_js);
+  let root_names = get_tsc_roots(&segment_graph_data, check_js);
   if options.log_checks {
     for (root, _) in roots {
       let root_str = root.to_string();

cli/tests/integration/run_tests.rs

@@ -2701,6 +2701,13 @@ fn check_local_then_remote() {
   assert_contains!(stderr, "Type 'string' is not assignable to type 'number'.");
 }
 
+// Regression test for https://github.com/denoland/deno/issues/15163
+itest!(check_js_points_to_ts {
+  args: "run --quiet --check --config checkjs.tsconfig.json run/check_js_points_to_ts/test.js",
+  output: "run/check_js_points_to_ts/test.js.out",
+  exit_code: 1,
+});
+
 itest!(no_prompt_flag {
   args: "run --quiet --unstable --no-prompt no_prompt.ts",
   output_str: Some(""),

cli/tests/testdata/run/check_js_points_to_ts/bar.ts

@@ -0,0 +1,3 @@
+export function bar(): string {
+  return 42;
+}

cli/tests/testdata/run/check_js_points_to_ts/foo.js

@@ -0,0 +1,4 @@
+import { bar } from "./bar.ts";
+export function foo() {
+  bar();
+}

cli/tests/testdata/run/check_js_points_to_ts/test.js

@@ -0,0 +1,3 @@
+// @deno-types="./foo.d.ts"
+import { foo } from "./foo.js";
+foo();

cli/tests/testdata/run/check_js_points_to_ts/test.js.out

@@ -0,0 +1,4 @@
+error: TS2322 [ERROR]: Type 'number' is not assignable to type 'string'.
+  return 42;
+  ~~~~~~~~~~
+    at [WILDCARD]