From 84ef9bd21fb48fb6b5fbc8dafc3de9f361bade3b Mon Sep 17 00:00:00 2001
From: Yosi Pramajaya <yosi.pramajaya@gmail.com>
Date: Sun, 13 Dec 2020 02:41:43 +0700
Subject: [PATCH] fix(cli/compile): error when the output path already exists
 (#8681)

---
 cli/standalone.rs              | 19 +++++++
 cli/tests/integration_tests.rs | 98 ++++++++++++++++++++++++++++++++++
 2 files changed, 117 insertions(+)

diff --git a/cli/standalone.rs b/cli/standalone.rs
index 067fec36a1..6559242bdb 100644
--- a/cli/standalone.rs
+++ b/cli/standalone.rs
@@ -5,6 +5,7 @@ use crate::tokio_util;
 use crate::version;
 use crate::worker::MainWorker;
 use crate::worker::WorkerOptions;
+use deno_core::error::bail;
 use deno_core::error::type_error;
 use deno_core::error::AnyError;
 use deno_core::futures::FutureExt;
@@ -169,6 +170,24 @@ pub async fn create_standalone_binary(
     } else {
       output
     };
+
+  if output.exists() {
+    // If the output is a directory, throw error
+    if output.is_dir() {
+      bail!("Could not compile: {:?} is a directory.", &output);
+    }
+
+    // Make sure we don't overwrite any file not created by Deno compiler.
+    // Check for magic trailer in last 16 bytes
+    let mut output_file = File::open(&output)?;
+    output_file.seek(SeekFrom::End(-16))?;
+    let mut trailer = [0; 16];
+    output_file.read_exact(&mut trailer)?;
+    let (magic_trailer, _) = trailer.split_at(8);
+    if magic_trailer != MAGIC_TRAILER {
+      bail!("Could not compile: cannot overwrite {:?}.", &output);
+    }
+  }
   tokio::fs::write(&output, final_bin).await?;
   #[cfg(unix)]
   {
diff --git a/cli/tests/integration_tests.rs b/cli/tests/integration_tests.rs
index eeffb00970..cb6dfad6d9 100644
--- a/cli/tests/integration_tests.rs
+++ b/cli/tests/integration_tests.rs
@@ -4650,3 +4650,101 @@ fn standalone_no_module_load() {
   assert!(util::strip_ansi_codes(&stderr_str)
     .contains("Self-contained binaries don't support module loading"));
 }
+
+#[test]
+fn compile_with_directory_exists_error() {
+  let dir = TempDir::new().expect("tempdir fail");
+  let exe = if cfg!(windows) {
+    dir.path().join("args.exe")
+  } else {
+    dir.path().join("args")
+  };
+  std::fs::create_dir(&exe).expect("cannot create directory");
+  let output = util::deno_cmd()
+    .current_dir(util::root_path())
+    .arg("compile")
+    .arg("--unstable")
+    .arg("./cli/tests/028_args.ts")
+    .arg("--output")
+    .arg(&exe)
+    .stderr(std::process::Stdio::piped())
+    .spawn()
+    .unwrap()
+    .wait_with_output()
+    .unwrap();
+  assert!(!output.status.success());
+  let expected_stderr =
+    format!("Could not compile: {:?} is a directory.\n", &exe);
+  let stderr = String::from_utf8(output.stderr).unwrap();
+  assert!(stderr.contains(&expected_stderr));
+}
+
+#[test]
+fn compile_with_conflict_file_exists_error() {
+  let dir = TempDir::new().expect("tempdir fail");
+  let exe = if cfg!(windows) {
+    dir.path().join("args.exe")
+  } else {
+    dir.path().join("args")
+  };
+  std::fs::write(&exe, b"SHOULD NOT BE OVERWRITTEN")
+    .expect("cannot create file");
+  let output = util::deno_cmd()
+    .current_dir(util::root_path())
+    .arg("compile")
+    .arg("--unstable")
+    .arg("./cli/tests/028_args.ts")
+    .arg("--output")
+    .arg(&exe)
+    .stderr(std::process::Stdio::piped())
+    .spawn()
+    .unwrap()
+    .wait_with_output()
+    .unwrap();
+  assert!(!output.status.success());
+  let expected_stderr =
+    format!("Could not compile: cannot overwrite {:?}.\n", &exe);
+  let stderr = String::from_utf8(output.stderr).unwrap();
+  assert!(stderr.contains(&expected_stderr));
+  assert!(std::fs::read(&exe)
+    .expect("cannot read file")
+    .eq(b"SHOULD NOT BE OVERWRITTEN"));
+}
+
+#[test]
+fn compile_and_overwrite_file() {
+  let dir = TempDir::new().expect("tempdir fail");
+  let exe = if cfg!(windows) {
+    dir.path().join("args.exe")
+  } else {
+    dir.path().join("args")
+  };
+  let output = util::deno_cmd()
+    .current_dir(util::root_path())
+    .arg("compile")
+    .arg("--unstable")
+    .arg("./cli/tests/028_args.ts")
+    .arg("--output")
+    .arg(&exe)
+    .stderr(std::process::Stdio::piped())
+    .spawn()
+    .unwrap()
+    .wait_with_output()
+    .unwrap();
+  assert!(output.status.success());
+  assert!(&exe.exists());
+
+  let recompile_output = util::deno_cmd()
+    .current_dir(util::root_path())
+    .arg("compile")
+    .arg("--unstable")
+    .arg("./cli/tests/028_args.ts")
+    .arg("--output")
+    .arg(&exe)
+    .stderr(std::process::Stdio::piped())
+    .spawn()
+    .unwrap()
+    .wait_with_output()
+    .unwrap();
+  assert!(recompile_output.status.success());
+}