3 files changed, 115 insertions, 0 deletions
diff --git a/cli/dts/lib.deno.ns.d.ts b/cli/dts/lib.deno.ns.d.ts
index 9c645882d..c01ac80fb 100644
--- a/cli/dts/lib.deno.ns.d.ts
+++ b/cli/dts/lib.deno.ns.d.ts
@@ -4017,6 +4017,14 @@ declare namespace Deno {
    * }
    * ```
    *
+   * Note that this function *consumes* the given connection passed to it, thus the
+   * original connection will be unusable after calling this. Additionally, you
+   * need to ensure that the connection is not being used elsewhere when calling
+   * this function in order for the connection to be consumed properly.
+   * For instance, if there is a `Promise` that is waiting for read operation on
+   * the connection to complete, it is considered that the connection is being
+   * used elsewhere. In such a case, this function will fail.
+   *
    * @category HTTP Server
    */
   export function serveHttp(conn: Conn): HttpConn;
diff --git a/cli/tests/unit/http_test.ts b/cli/tests/unit/http_test.ts
index 63eae3ace..566efce6d 100644
--- a/cli/tests/unit/http_test.ts
+++ b/cli/tests/unit/http_test.ts
@@ -2373,6 +2373,86 @@ Deno.test(
   },
 );
 
+Deno.test(
+  {
+    permissions: { net: true },
+  },
+  async function httpServerWithoutExclusiveAccessToTcp() {
+    const port = 4506;
+    const listener = Deno.listen({ port });
+
+    const [clientConn, serverConn] = await Promise.all([
+      Deno.connect({ port }),
+      listener.accept(),
+    ]);
+
+    const buf = new Uint8Array(128);
+    const readPromise = serverConn.read(buf);
+    assertThrows(() => Deno.serveHttp(serverConn), Deno.errors.BadResource);
+
+    clientConn.close();
+    listener.close();
+    await readPromise;
+  },
+);
+
+Deno.test(
+  {
+    permissions: { net: true, read: true },
+  },
+  async function httpServerWithoutExclusiveAccessToTls() {
+    const hostname = "localhost";
+    const port = 4507;
+    const listener = Deno.listenTls({
+      hostname,
+      port,
+      certFile: "cli/tests/testdata/tls/localhost.crt",
+      keyFile: "cli/tests/testdata/tls/localhost.key",
+    });
+
+    const caCerts = [
+      await Deno.readTextFile("cli/tests/testdata/tls/RootCA.pem"),
+    ];
+    const [clientConn, serverConn] = await Promise.all([
+      Deno.connectTls({ hostname, port, caCerts }),
+      listener.accept(),
+    ]);
+    await Promise.all([clientConn.handshake(), serverConn.handshake()]);
+
+    const buf = new Uint8Array(128);
+    const readPromise = serverConn.read(buf);
+    assertThrows(() => Deno.serveHttp(serverConn), Deno.errors.BadResource);
+
+    clientConn.close();
+    listener.close();
+    await readPromise;
+  },
+);
+
+Deno.test(
+  {
+    ignore: Deno.build.os === "windows",
+    permissions: { read: true, write: true },
+  },
+  async function httpServerWithoutExclusiveAccessToUnixSocket() {
+    const filePath = await Deno.makeTempFile();
+    const listener = Deno.listen({ path: filePath, transport: "unix" });
+
+    const [clientConn, serverConn] = await Promise.all([
+      Deno.connect({ path: filePath, transport: "unix" }),
+      listener.accept(),
+    ]);
+
+    const buf = new Uint8Array(128);
+    const readPromise = serverConn.read(buf);
+    assertThrows(() => Deno.serveHttp(serverConn), Deno.errors.BadResource);
+
+    clientConn.close();
+    listener.close();
+    await readPromise;
+  },
+);
+
 function chunkedBodyReader(h: Headers, r: BufReader): Deno.Reader {
   // Based on https://tools.ietf.org/html/rfc2616#section-19.4.6
   const tp = new TextProtoReader(r);
diff --git a/cli/tests/unit/tls_test.ts b/cli/tests/unit/tls_test.ts
index cf335de49..860965e49 100644
--- a/cli/tests/unit/tls_test.ts
+++ b/cli/tests/unit/tls_test.ts
@@ -148,6 +148,33 @@ Deno.test(
 );
 
 Deno.test(
+  { permissions: { net: true } },
+  async function startTlsWithoutExclusiveAccessToTcpConn() {
+    const hostname = "localhost";
+    const port = getPort();
+
+    const tcpListener = Deno.listen({ hostname, port });
+    const [serverConn, clientConn] = await Promise.all([
+      tcpListener.accept(),
+      Deno.connect({ hostname, port }),
+    ]);
+
+    const buf = new Uint8Array(128);
+    const readPromise = clientConn.read(buf);
+    // `clientConn` is being used by a pending promise (`readPromise`) so
+    // `Deno.startTls` cannot consume the connection.
+    await assertRejects(
+      () => Deno.startTls(clientConn, { hostname }),
+      Deno.errors.BadResource,
+    );
+
+    serverConn.close();
+    tcpListener.close();
+    await readPromise;
+  },
+);
+
+Deno.test(
   { permissions: { read: true, net: true } },
   async function dialAndListenTLS() {
     const resolvable = deferred();