fix(typescript): don't declare outputs that collide with inputs (#3046)

packages/typescript/internal/ts_project.bzl

@@ -340,11 +340,16 @@ def _replace_ext(f, ext_map):
 
 def _out_paths(srcs, outdir, rootdir, allow_js, ext_map):
     rootdir_replace_pattern = rootdir + "/" if rootdir else ""
-    return [
-        _join(outdir, f[:f.rindex(".")].replace(rootdir_replace_pattern, "") + _replace_ext(f, ext_map))
-        for f in srcs
-        if _is_ts_src(f, allow_js)
-    ]
+    outs = []
+    for f in srcs:
+        if _is_ts_src(f, allow_js):
+            out = _join(outdir, f[:f.rindex(".")].replace(rootdir_replace_pattern, "") + _replace_ext(f, ext_map))
+
+            # Don't declare outputs that collide with inputs
+            # for example, a.js -> a.js
+            if out != f:
+                outs.append(out)
+    return outs
 
 def ts_project_macro(
         name = "tsconfig",

packages/typescript/test/ts_project/allow_js/BUILD.bazel

@@ -4,6 +4,7 @@ load("//packages/typescript:index.bzl", "ts_project")
 # Ensure that a.js produces outDir/a.js, outDir/a.d.ts, and outDir/a.d.ts.map
 SRCS = [
     "a.js",
+    "b.jsx",
 ]
 
 ts_project(
@@ -34,3 +35,14 @@ nodejs_test(
         "$(locations :transpile)",
     ],
 )
+
+# Test that we can write outputs to the same folder as the inputs
+# ts_project shouldn't try to declare a.js as an output in this case
+ts_project(
+    name = "transpile_to_same_dir",
+    srcs = SRCS,
+    allow_js = True,
+    declaration = True,
+    declaration_map = True,
+    source_map = True,
+)

packages/typescript/test/ts_project/allow_js/b.jsx

@@ -0,0 +1,3 @@
+'use strict';
+exports.__esModule = true;
+exports.b = <b></b>;

packages/typescript/test/ts_project/allow_js/verify.js

@@ -1,7 +1,8 @@
 const assert = require('assert');
 
-const types_files = process.argv.slice(2, 4);
-const code_file = process.argv[4];
-assert.ok(types_files.some(f => f.endsWith('out/a.d.ts')), 'Missing a.d.ts');
-assert.ok(types_files.some(f => f.endsWith('out/a.d.ts.map')), 'Missing a.d.ts.map');
-assert.ok(code_file.endsWith('out/a.js'), 'Missing a.js');
+const output_files = process.argv.slice(2);
+for (const file of ['a', 'b']) {
+    assert.ok(output_files.some(f => f.endsWith(`out/${file}.d.ts`)), `Missing ${file}.d.ts`);
+    assert.ok(output_files.some(f => f.endsWith(`out/${file}.d.ts.map`)), `Missing ${file}.d.ts.map`);
+    assert.ok(output_files.some(f => f.endsWith(`out/${file}.js`)), `Missing ${file}.js`);
+}