feat(repl): add "--eval-file" flag to execute a script file on startup (#14247)

This commit adds support for "--eval-file" in "deno repl" subcommand.

This flag can be used to pass paths or URLs to files, that will be executed
on REPL startup. All files will be executed in the same context as the REPL
(ie. as "plain old scripts", not ES modules), sharing the global scope.

This feature allows to implement custom REPLs on top of Deno's REPL.

4 files changed, 159 insertions, 6 deletions

diff --git a/cli/flags.rs b/cli/flags.rs
index cdd90fa33..b0e4b32ed 100644
--- a/cli/flags.rs
+++ b/cli/flags.rs
@@ -144,6 +144,7 @@ pub struct LintFlags {
 
 #[derive(Clone, Debug, PartialEq, Deserialize, Serialize)]
 pub struct ReplFlags {
+  pub eval_files: Option<Vec<String>>,
   pub eval: Option<String>,
 }
 
@@ -216,7 +217,10 @@ pub enum DenoSubcommand {
 
 impl Default for DenoSubcommand {
   fn default() -> DenoSubcommand {
-    DenoSubcommand::Repl(ReplFlags { eval: None })
+    DenoSubcommand::Repl(ReplFlags {
+      eval_files: None,
+      eval: None,
+    })
   }
 }
 
@@ -556,7 +560,13 @@ where
     Some(("uninstall", m)) => uninstall_parse(&mut flags, m),
     Some(("upgrade", m)) => upgrade_parse(&mut flags, m),
     Some(("vendor", m)) => vendor_parse(&mut flags, m),
-    _ => handle_repl_flags(&mut flags, ReplFlags { eval: None }),
+    _ => handle_repl_flags(
+      &mut flags,
+      ReplFlags {
+        eval_files: None,
+        eval: None,
+      },
+    ),
   }
 
   Ok(flags)
@@ -1361,6 +1371,16 @@ fn repl_subcommand<'a>() -> Command<'a> {
   runtime_args(Command::new("repl"), false, true)
     .about("Read Eval Print Loop")
     .arg(
+      Arg::new("eval-file")
+        .long("eval-file")
+        .min_values(1)
+        .takes_value(true)
+        .use_value_delimiter(true)
+        .require_equals(true)
+        .help("Evaluates the provided file(s) as scripts when the REPL starts. Accepts file paths and URLs.")
+        .value_hint(ValueHint::AnyPath),
+    )
+    .arg(
       Arg::new("eval")
         .long("eval")
         .help("Evaluates the provided code when the REPL starts.")
@@ -2446,9 +2466,15 @@ fn repl_parse(flags: &mut Flags, matches: &clap::ArgMatches) {
   flags.type_check_mode = TypeCheckMode::None;
   runtime_args_parse(flags, matches, false, true);
   unsafely_ignore_certificate_errors_parse(flags, matches);
+
+  let eval_files: Option<Vec<String>> = matches
+    .values_of("eval-file")
+    .map(|values| values.map(String::from).collect());
+
   handle_repl_flags(
     flags,
     ReplFlags {
+      eval_files,
       eval: matches.value_of("eval").map(ToOwned::to_owned),
     },
   );
@@ -3884,7 +3910,10 @@ mod tests {
       r.unwrap(),
       Flags {
         repl: true,
-        subcommand: DenoSubcommand::Repl(ReplFlags { eval: None }),
+        subcommand: DenoSubcommand::Repl(ReplFlags {
+          eval_files: None,
+          eval: None
+        }),
         allow_net: Some(vec![]),
         unsafely_ignore_certificate_errors: None,
         allow_env: Some(vec![]),
@@ -3906,7 +3935,10 @@ mod tests {
       r.unwrap(),
       Flags {
         repl: true,
-        subcommand: DenoSubcommand::Repl(ReplFlags { eval: None }),
+        subcommand: DenoSubcommand::Repl(ReplFlags {
+          eval_files: None,
+          eval: None
+        }),
         import_map_path: Some("import_map.json".to_string()),
         no_remote: true,
         config_path: Some("tsconfig.json".to_string()),
@@ -3942,6 +3974,7 @@ mod tests {
       Flags {
         repl: true,
         subcommand: DenoSubcommand::Repl(ReplFlags {
+          eval_files: None,
           eval: Some("console.log('hello');".to_string()),
         }),
         allow_net: Some(vec![]),
@@ -3958,6 +3991,35 @@ mod tests {
   }
 
   #[test]
+  fn repl_with_eval_file_flag() {
+    #[rustfmt::skip]
+    let r = flags_from_vec(svec!["deno", "repl", "--eval-file=./a.js,./b.ts,https://examples.deno.land/hello-world.ts"]);
+    assert_eq!(
+      r.unwrap(),
+      Flags {
+        repl: true,
+        subcommand: DenoSubcommand::Repl(ReplFlags {
+          eval_files: Some(vec![
+            "./a.js".to_string(),
+            "./b.ts".to_string(),
+            "https://examples.deno.land/hello-world.ts".to_string()
+          ]),
+          eval: None,
+        }),
+        allow_net: Some(vec![]),
+        allow_env: Some(vec![]),
+        allow_run: Some(vec![]),
+        allow_read: Some(vec![]),
+        allow_write: Some(vec![]),
+        allow_ffi: Some(vec![]),
+        allow_hrtime: true,
+        type_check_mode: TypeCheckMode::None,
+        ..Flags::default()
+      }
+    );
+  }
+
+  #[test]
   fn allow_read_allowlist() {
     use test_util::TempDir;
     let temp_dir_guard = TempDir::new();
@@ -4590,6 +4652,7 @@ mod tests {
       Flags {
         repl: true,
         subcommand: DenoSubcommand::Repl(ReplFlags {
+          eval_files: None,
           eval: Some("console.log('hello');".to_string()),
         }),
         unsafely_ignore_certificate_errors: Some(vec![]),
@@ -4663,7 +4726,10 @@ mod tests {
       r.unwrap(),
       Flags {
         repl: true,
-        subcommand: DenoSubcommand::Repl(ReplFlags { eval: None }),
+        subcommand: DenoSubcommand::Repl(ReplFlags {
+          eval_files: None,
+          eval: None
+        }),
         unsafely_ignore_certificate_errors: Some(svec![
           "deno.land",
           "localhost",
diff --git a/cli/main.rs b/cli/main.rs
index 7f86967aa..218bc70f5 100644
--- a/cli/main.rs
+++ b/cli/main.rs
@@ -930,7 +930,7 @@ async fn repl_command(
   }
   worker.run_event_loop(false).await?;
 
-  tools::repl::run(&ps, worker, repl_flags.eval).await
+  tools::repl::run(&ps, worker, repl_flags.eval_files, repl_flags.eval).await
 }
 
 async fn run_from_stdin(flags: Flags) -> Result<i32, AnyError> {
diff --git a/cli/tests/integration/repl_tests.rs b/cli/tests/integration/repl_tests.rs
index 59acc7dfb..a63be3ece 100644
--- a/cli/tests/integration/repl_tests.rs
+++ b/cli/tests/integration/repl_tests.rs
@@ -709,3 +709,55 @@ fn eval_flag_runtime_error() {
   assert!(out.contains("2500")); // should not prevent input
   assert!(err.is_empty());
 }
+
+#[test]
+fn eval_file_flag_valid_input() {
+  let (out, err) = util::run_and_collect_output_with_args(
+    true,
+    vec!["repl", "--eval-file=./001_hello.js"],
+    None,
+    None,
+    false,
+  );
+  assert!(out.contains("Hello World"));
+  assert!(err.is_empty());
+}
+
+#[test]
+fn eval_file_flag_call_defined_function() {
+  let (out, err) = util::run_and_collect_output_with_args(
+    true,
+    vec!["repl", "--eval-file=./tsc/d.ts"],
+    Some(vec!["v4()"]),
+    None,
+    false,
+  );
+  assert!(out.contains("hello"));
+  assert!(err.is_empty());
+}
+
+#[test]
+fn eval_file_flag_http_input() {
+  let (out, err) = util::run_and_collect_output_with_args(
+    true,
+    vec!["repl", "--eval-file=http://127.0.0.1:4545/tsc/d.ts"],
+    Some(vec!["v4()"]),
+    None,
+    true,
+  );
+  assert!(out.contains("hello"));
+  assert!(err.contains("Download"));
+}
+
+#[test]
+fn eval_file_flag_multiple_files() {
+  let (out, err) = util::run_and_collect_output_with_args(
+    true,
+    vec!["repl", "--eval-file=http://127.0.0.1:4545/import_type.ts,./tsc/d.ts,http://127.0.0.1:4545/type_definitions/foo.js"],
+    Some(vec!["b.method1=v4", "b.method1()+foo.toUpperCase()"]),
+    None,
+    true,
+  );
+  assert!(out.contains("helloFOO"));
+  assert!(err.contains("Download"));
+}
diff --git a/cli/tools/repl/mod.rs b/cli/tools/repl/mod.rs
index b49c641c4..f0964ec4d 100644
--- a/cli/tools/repl/mod.rs
+++ b/cli/tools/repl/mod.rs
@@ -2,6 +2,7 @@
 
 use crate::proc_state::ProcState;
 use deno_core::error::AnyError;
+use deno_runtime::permissions::Permissions;
 use deno_runtime::worker::MainWorker;
 use rustyline::error::ReadlineError;
 
@@ -58,9 +59,24 @@ async fn read_line_and_poll(
   }
 }
 
+async fn read_eval_file(
+  ps: &ProcState,
+  eval_file: &str,
+) -> Result<String, AnyError> {
+  let specifier = deno_core::resolve_url_or_path(eval_file)?;
+
+  let file = ps
+    .file_fetcher
+    .fetch(&specifier, &mut Permissions::allow_all())
+    .await?;
+
+  Ok((*file.source).clone())
+}
+
 pub async fn run(
   ps: &ProcState,
   worker: MainWorker,
+  maybe_eval_files: Option<Vec<String>>,
   maybe_eval: Option<String>,
 ) -> Result<i32, AnyError> {
   let mut repl_session = ReplSession::initialize(worker).await?;
@@ -74,6 +90,25 @@ pub async fn run(
   let history_file_path = ps.dir.root.join("deno_history.txt");
   let editor = ReplEditor::new(helper, history_file_path);
 
+  if let Some(eval_files) = maybe_eval_files {
+    for eval_file in eval_files {
+      match read_eval_file(ps, &eval_file).await {
+        Ok(eval_source) => {
+          let output = repl_session
+            .evaluate_line_and_get_output(&eval_source)
+            .await?;
+          // only output errors
+          if let EvaluationOutput::Error(error_text) = output {
+            println!("error in --eval-file file {}. {}", eval_file, error_text);
+          }
+        }
+        Err(e) => {
+          println!("error in --eval-file file {}. {}", eval_file, e);
+        }
+      }
+    }
+  }
+
   if let Some(eval) = maybe_eval {
     let output = repl_session.evaluate_line_and_get_output(&eval).await?;
     // only output errors