fix(std/bufio): Remove '\r' at the end of Windows lines (#8447)

Co-authored-by: Nayeem Rahman <nayeemrmn99@gmail.com>

2 files changed, 21 insertions, 1 deletions

diff --git a/std/io/bufio.ts b/std/io/bufio.ts
index 954fc5eee..df3ecb002 100644
--- a/std/io/bufio.ts
+++ b/std/io/bufio.ts
@@ -706,5 +706,13 @@ export async function* readStringDelim(
 export async function* readLines(
   reader: Reader,
 ): AsyncIterableIterator<string> {
-  yield* readStringDelim(reader, "\n");
+  for await (let chunk of readStringDelim(reader, "\n")) {
+    // Finding a CR at the end of the line is evidence of a
+    // "\r\n" at the end of the line. The "\r" part should be
+    // removed too.
+    if (chunk.endsWith("\r")) {
+      chunk = chunk.slice(0, -1);
+    }
+    yield chunk;
+  }
 }
diff --git a/std/io/bufio_test.ts b/std/io/bufio_test.ts
index 03f699d50..804d59e99 100644
--- a/std/io/bufio_test.ts
+++ b/std/io/bufio_test.ts
@@ -436,6 +436,10 @@ Deno.test("readStringDelimAndLines", async function (): Promise<void> {
   assertEquals(chunks_, ["Hello World", "Hello World 2", "Hello World 3"]);
 
   const linesData = new Deno.Buffer(enc.encode("0\n1\n2\n3\n4\n5\n6\n7\n8\n9"));
+  // consider data with windows newlines too
+  const linesDataWindows = new Deno.Buffer(
+    enc.encode("0\r\n1\r\n2\r\n3\r\n4\r\n5\r\n6\r\n7\r\n8\r\n9"),
+  );
   const lines_ = [];
 
   for await (const l of readLines(linesData)) {
@@ -444,6 +448,14 @@ Deno.test("readStringDelimAndLines", async function (): Promise<void> {
 
   assertEquals(lines_.length, 10);
   assertEquals(lines_, ["0", "1", "2", "3", "4", "5", "6", "7", "8", "9"]);
+
+  // Now test for "windows" lines
+  lines_.length = 0;
+  for await (const l of readLines(linesDataWindows)) {
+    lines_.push(l);
+  }
+  assertEquals(lines_.length, 10);
+  assertEquals(lines_, ["0", "1", "2", "3", "4", "5", "6", "7", "8", "9"]);
 });
 
 Deno.test(