feat: deno run with no arguments prints list of available tasks

cli/args/flags.rs

@@ -339,6 +339,7 @@ pub struct RunFlags {
   pub watch: Option<WatchFlagsWithPaths>,
   pub bare: bool,
   pub coverage_dir: Option<String>,
+  pub print_task_list: bool,
 }
 
 impl RunFlags {
@@ -349,6 +350,7 @@ impl RunFlags {
       watch: None,
       bare: false,
       coverage_dir: None,
+      print_task_list: false,
     }
   }
 
@@ -5745,7 +5747,7 @@ fn repl_parse(
 fn run_parse(
   flags: &mut Flags,
   matches: &mut ArgMatches,
-  mut app: Command,
+  app: Command,
   bare: bool,
 ) -> clap::error::Result<()> {
   runtime_args_parse(flags, matches, true, true, true)?;
@@ -5764,6 +5766,7 @@ fn run_parse(
         watch: watch_arg_parse_with_paths(matches)?,
         bare,
         coverage_dir,
+        print_task_list: false,
       });
     }
     _ => {
@@ -5773,10 +5776,14 @@ fn run_parse(
       "[SCRIPT_ARG] may only be omitted with --v8-flags=--help, else to use the repl with arguments, please use the `deno repl` subcommand",
     ));
       } else {
-        return Err(app.find_subcommand_mut("run").unwrap().error(
-          clap::error::ErrorKind::MissingRequiredArgument,
-          "[SCRIPT_ARG] may only be omitted with --v8-flags=--help",
-        ));
+        // When no script argument is provided, show available tasks like `deno task`
+        flags.subcommand = DenoSubcommand::Run(RunFlags {
+          script: "".to_string(),
+          watch: None,
+          bare: false,
+          coverage_dir: None,
+          print_task_list: true,
+        });
       }
     }
   }
@@ -6743,6 +6750,7 @@ mod tests {
           }),
           bare: false,
           coverage_dir: None,
+          print_task_list: false,
         }),
         code_cache_enabled: true,
         ..Flags::default()
@@ -6769,6 +6777,7 @@ mod tests {
           }),
           bare: true,
           coverage_dir: None,
+          print_task_list: false,
         }),
         code_cache_enabled: true,
         ..Flags::default()
@@ -6796,6 +6805,7 @@ mod tests {
           }),
           bare: false,
           coverage_dir: None,
+          print_task_list: false,
         }),
         code_cache_enabled: true,
         ..Flags::default()
@@ -6823,6 +6833,7 @@ mod tests {
           }),
           bare: false,
           coverage_dir: None,
+          print_task_list: false,
         }),
         code_cache_enabled: true,
         ..Flags::default()
@@ -6850,6 +6861,7 @@ mod tests {
           }),
           bare: false,
           coverage_dir: None,
+          print_task_list: false,
         }),
         code_cache_enabled: true,
         ..Flags::default()
@@ -6878,6 +6890,7 @@ mod tests {
           }),
           bare: true,
           coverage_dir: None,
+          print_task_list: false,
         }),
         code_cache_enabled: true,
         ..Flags::default()
@@ -6909,6 +6922,7 @@ mod tests {
           }),
           bare: false,
           coverage_dir: None,
+          print_task_list: false,
         }),
         code_cache_enabled: true,
         ..Flags::default()
@@ -6939,6 +6953,7 @@ mod tests {
           }),
           bare: true,
           coverage_dir: None,
+          print_task_list: false,
         }),
         code_cache_enabled: true,
         ..Flags::default()
@@ -6966,6 +6981,7 @@ mod tests {
           }),
           bare: false,
           coverage_dir: None,
+          print_task_list: false,
         }),
         code_cache_enabled: true,
         ..Flags::default()
@@ -6994,6 +7010,7 @@ mod tests {
           }),
           bare: false,
           coverage_dir: None,
+          print_task_list: false,
         }),
         code_cache_enabled: true,
         ..Flags::default()
@@ -7021,6 +7038,7 @@ mod tests {
           }),
           bare: true,
           coverage_dir: None,
+          print_task_list: false,
         }),
         code_cache_enabled: true,
         ..Flags::default()
@@ -7060,6 +7078,7 @@ mod tests {
           watch: None,
           bare: false,
           coverage_dir: Some("foo".to_string()),
+          print_task_list: false,
         }),
         code_cache_enabled: true,
         ..Flags::default()
@@ -7376,6 +7395,7 @@ mod tests {
           watch: None,
           bare: true,
           coverage_dir: None,
+          print_task_list: false,
         }),
         permissions: PermissionFlags {
           deny_read: Some(vec![]),
@@ -8666,6 +8686,7 @@ mod tests {
           watch: None,
           bare: true,
           coverage_dir: None,
+          print_task_list: false,
         }),
         permissions: PermissionFlags {
           deny_net: Some(svec!["127.0.0.1"]),
@@ -8854,6 +8875,7 @@ mod tests {
           watch: None,
           bare: true,
           coverage_dir: None,
+          print_task_list: false,
         }),
         permissions: PermissionFlags {
           deny_sys: Some(svec!["hostname"]),
@@ -9154,6 +9176,7 @@ mod tests {
           watch: None,
           bare: true,
           coverage_dir: None,
+          print_task_list: false,
         }),
         ..Flags::default()
       }
@@ -9465,6 +9488,7 @@ mod tests {
           watch: None,
           bare: true,
           coverage_dir: None,
+          print_task_list: false,
         }),
         log_level: Some(Level::Error),
         code_cache_enabled: true,
@@ -9586,6 +9610,7 @@ mod tests {
           watch: None,
           bare: true,
           coverage_dir: None,
+          print_task_list: false,
         }),
         type_check_mode: TypeCheckMode::None,
         code_cache_enabled: true,
@@ -9758,6 +9783,7 @@ mod tests {
           watch: None,
           bare: true,
           coverage_dir: None,
+          print_task_list: false,
         }),
         node_modules_dir: Some(NodeModulesDirMode::Auto),
         code_cache_enabled: true,
@@ -10982,6 +11008,7 @@ mod tests {
           watch: None,
           bare: true,
           coverage_dir: None,
+          print_task_list: false,
         }),
         inspect_wait: Some("127.0.0.1:9229".parse().unwrap()),
         code_cache_enabled: true,
@@ -11676,6 +11703,7 @@ mod tests {
           watch: None,
           bare: true,
           coverage_dir: None,
+          print_task_list: false,
         }),
         type_check_mode: TypeCheckMode::None,
         code_cache_enabled: true,
@@ -12230,6 +12258,7 @@ mod tests {
           watch: None,
           bare: true,
           coverage_dir: None,
+          print_task_list: false,
         }),
         config_flag: ConfigFlag::Disabled,
         code_cache_enabled: true,

cli/main.rs

@@ -33,6 +33,7 @@ use std::collections::HashMap;
 use std::env;
 use std::future::Future;
 use std::io::IsTerminal;
+use std::io::Write as _;
 use std::ops::Deref;
 use std::path::PathBuf;
 use std::sync::Arc;
@@ -241,7 +242,27 @@ async fn run_subcommand(
       spawn_subcommand(async move { tools::repl::run(flags, repl_flags).await })
     }
     DenoSubcommand::Run(run_flags) => spawn_subcommand(async move {
-      if run_flags.is_stdin() {
+      if run_flags.print_task_list {
+        writeln!(
+          &mut std::io::stdout(),
+          "Please specify a {} or a {}.\n",
+          colors::bold("[SCRIPT_ARG]"),
+          colors::bold("task name")
+        )?;
+        std::io::stdout().flush()?;
+        tools::task::execute_script(
+          flags,
+          TaskFlags {
+            cwd: None,
+            task: None,
+            is_run: true,
+            recursive: false,
+            filter: None,
+            eval: false,
+          },
+        )
+        .await
+      } else if run_flags.is_stdin() {
         // these futures are boxed to prevent stack overflows on Windows
         tools::run::run_from_stdin(flags.clone(), unconfigured_runtime, roots)
           .boxed_local()

cli/tools/task.rs

@@ -63,7 +63,7 @@ pub async fn execute_script(
   let start_dir = &cli_options.start_dir;
   if !start_dir.has_deno_or_pkg_json() && !task_flags.eval {
     bail!(
-      "deno task couldn't find deno.json(c). See https://docs.deno.com/go/config"
+      "deno task couldn't find deno.json(c) or package.json. See https://docs.deno.com/go/config"
     )
   }
   let force_use_pkg_json =

tests/specs/run/run_without_script_argument/__test__.jsonc

@@ -0,0 +1,5 @@
+{
+  "args": "run -q --config deno.json",
+  "output": "run_without_script_argument.out",
+  "exitCode": 0
+}

tests/specs/run/run_without_script_argument/deno.json

@@ -0,0 +1,9 @@
+{
+  "tasks": {
+    "dev": "deno run --watch --allow-net server.ts",
+    "test": "deno test --allow-read tests/",
+    "build": "deno compile --allow-net --output=./dist/app server.ts",
+    "lint": "deno lint",
+    "fmt": "deno fmt"
+  }
+}

tests/specs/run/run_without_script_argument/run_without_script_argument.out

@@ -0,0 +1,13 @@
+Please specify a [SCRIPT_ARG] or a task name.
+
+Available tasks:
+- dev
+    deno run --watch --allow-net server.ts
+- test
+    deno test --allow-read tests/
+- build
+    deno compile --allow-net --output=./dist/app server.ts
+- lint
+    deno lint
+- fmt
+    deno fmt