feat: add `--watch-exclude` flag (#21935)

This PR introduces the ability to exclude certain paths from the file watcher
in Deno. This is particularly useful when running scripts in watch mode,
as it allows developers to prevent unnecessary restarts when changes are
made to files that do not affect the running script, or when executing
scripts that generate new files which results in an infinite restart
loop.

---------

Co-authored-by: David Sherret <dsherret@gmail.com>

1 files changed, 210 insertions, 0 deletions

diff --git a/cli/args/flags.rs b/cli/args/flags.rs
index 1bd30bd68..804e766a2 100644
--- a/cli/args/flags.rs
+++ b/cli/args/flags.rs
@@ -9,7 +9,10 @@ use clap::ArgMatches;
 use clap::ColorChoice;
 use clap::Command;
 use clap::ValueHint;
+use deno_config::glob::PathOrPatternSet;
 use deno_config::ConfigFlag;
+use deno_core::anyhow::Context;
+use deno_core::error::AnyError;
 use deno_core::resolve_url_or_path;
 use deno_core::url::Url;
 use deno_graph::GraphKind;
@@ -249,6 +252,7 @@ impl RunFlags {
 pub struct WatchFlags {
   pub hmr: bool,
   pub no_clear_screen: bool,
+  pub exclude: Vec<String>,
 }
 
 #[derive(Clone, Default, Debug, Eq, PartialEq)]
@@ -256,6 +260,7 @@ pub struct WatchFlagsWithPaths {
   pub hmr: bool,
   pub paths: Vec<String>,
   pub no_clear_screen: bool,
+  pub exclude: Vec<String>,
 }
 
 #[derive(Clone, Debug, Eq, PartialEq)]
@@ -831,6 +836,69 @@ impl Flags {
     self.allow_ffi = Some(vec![]);
     self.allow_hrtime = true;
   }
+
+  pub fn resolve_watch_exclude_set(
+    &self,
+  ) -> Result<PathOrPatternSet, AnyError> {
+    if let DenoSubcommand::Run(RunFlags {
+      watch:
+        Some(WatchFlagsWithPaths {
+          exclude: excluded_paths,
+          ..
+        }),
+      ..
+    })
+    | DenoSubcommand::Bundle(BundleFlags {
+      watch:
+        Some(WatchFlags {
+          exclude: excluded_paths,
+          ..
+        }),
+      ..
+    })
+    | DenoSubcommand::Bench(BenchFlags {
+      watch:
+        Some(WatchFlags {
+          exclude: excluded_paths,
+          ..
+        }),
+      ..
+    })
+    | DenoSubcommand::Test(TestFlags {
+      watch:
+        Some(WatchFlags {
+          exclude: excluded_paths,
+          ..
+        }),
+      ..
+    })
+    | DenoSubcommand::Lint(LintFlags {
+      watch:
+        Some(WatchFlags {
+          exclude: excluded_paths,
+          ..
+        }),
+      ..
+    })
+    | DenoSubcommand::Fmt(FmtFlags {
+      watch:
+        Some(WatchFlags {
+          exclude: excluded_paths,
+          ..
+        }),
+      ..
+    }) = &self.subcommand
+    {
+      let cwd = std::env::current_dir()?;
+      PathOrPatternSet::from_exclude_relative_path_or_patterns(
+        &cwd,
+        excluded_paths,
+      )
+      .context("Failed resolving watch exclude patterns.")
+    } else {
+      Ok(PathOrPatternSet::default())
+    }
+  }
 }
 
 static ENV_VARIABLES_HELP: &str = color_print::cstr!(
@@ -1211,6 +1279,7 @@ glob {*_,*.,}bench.{js,mjs,ts,mts,jsx,tsx}:
             .action(ArgAction::SetTrue),
         )
         .arg(watch_arg(false))
+        .arg(watch_exclude_arg())
         .arg(no_clear_screen_arg())
         .arg(script_arg().last(true))
         .arg(env_file_arg())
@@ -1243,6 +1312,7 @@ If no output file is given, the output is written to standard output:
         )
         .arg(Arg::new("out_file").value_hint(ValueHint::FilePath))
         .arg(watch_arg(false))
+        .arg(watch_exclude_arg())
         .arg(no_clear_screen_arg())
         .arg(executable_ext_arg())
     })
@@ -1726,6 +1796,7 @@ Ignore formatting a file by adding an ignore comment at the top of the file:
             .value_hint(ValueHint::AnyPath),
         )
         .arg(watch_arg(false))
+        .arg(watch_exclude_arg())
         .arg(no_clear_screen_arg())
         .arg(
           Arg::new("use-tabs")
@@ -2095,6 +2166,7 @@ Ignore linting a file by adding an ignore comment at the top of the file:
             .value_hint(ValueHint::AnyPath),
         )
         .arg(watch_arg(false))
+        .arg(watch_exclude_arg())
         .arg(no_clear_screen_arg())
     })
 }
@@ -2126,6 +2198,7 @@ fn run_subcommand() -> Command {
   runtime_args(Command::new("run"), true, true)
     .arg(check_arg(false))
     .arg(watch_arg(true))
+    .arg(watch_exclude_arg())
     .arg(hmr_arg(true))
     .arg(no_clear_screen_arg())
     .arg(executable_ext_arg())
@@ -2308,6 +2381,7 @@ Directory arguments are expanded to all contained files matching the glob
         .conflicts_with("no-run")
         .conflicts_with("coverage"),
     )
+    .arg(watch_exclude_arg())
     .arg(no_clear_screen_arg())
     .arg(script_arg().last(true))
     .arg(
@@ -3120,6 +3194,18 @@ fn no_clear_screen_arg() -> Arg {
     .help("Do not clear terminal screen when under watch mode")
 }
 
+fn watch_exclude_arg() -> Arg {
+  Arg::new("watch-exclude")
+    .long("watch-exclude")
+    .help("Exclude provided files/patterns from watch mode")
+    .value_name("FILES")
+    .num_args(0..)
+    .value_parser(value_parser!(String))
+    .use_value_delimiter(true)
+    .require_equals(true)
+    .value_hint(ValueHint::AnyPath)
+}
+
 fn no_check_arg() -> Arg {
   Arg::new("no-check")
     .num_args(0..=1)
@@ -4263,6 +4349,10 @@ fn watch_arg_parse(matches: &mut ArgMatches) -> Option<WatchFlags> {
     Some(WatchFlags {
       hmr: false,
       no_clear_screen: matches.get_flag("no-clear-screen"),
+      exclude: matches
+        .remove_many::<String>("watch-exclude")
+        .map(|f| f.collect::<Vec<String>>())
+        .unwrap_or_default(),
     })
   } else {
     None
@@ -4277,6 +4367,10 @@ fn watch_arg_parse_with_paths(
       paths: paths.collect(),
       hmr: false,
       no_clear_screen: matches.get_flag("no-clear-screen"),
+      exclude: matches
+        .remove_many::<String>("watch-exclude")
+        .map(|f| f.collect::<Vec<String>>())
+        .unwrap_or_default(),
     });
   }
 
@@ -4286,6 +4380,10 @@ fn watch_arg_parse_with_paths(
       paths: paths.collect(),
       hmr: true,
       no_clear_screen: matches.get_flag("no-clear-screen"),
+      exclude: matches
+        .remove_many::<String>("watch-exclude")
+        .map(|f| f.collect::<Vec<String>>())
+        .unwrap_or_default(),
     })
 }
 
@@ -4424,6 +4522,7 @@ mod tests {
             hmr: false,
             paths: vec![],
             no_clear_screen: false,
+            exclude: vec![],
           }),
         }),
         ..Flags::default()
@@ -4447,6 +4546,7 @@ mod tests {
             hmr: false,
             paths: vec![],
             no_clear_screen: true,
+            exclude: vec![],
           }),
         }),
         ..Flags::default()
@@ -4470,6 +4570,7 @@ mod tests {
             hmr: true,
             paths: vec![],
             no_clear_screen: true,
+            exclude: vec![],
           }),
         }),
         ..Flags::default()
@@ -4493,6 +4594,7 @@ mod tests {
             hmr: true,
             paths: vec![String::from("foo.txt")],
             no_clear_screen: true,
+            exclude: vec![],
           }),
         }),
         ..Flags::default()
@@ -4518,6 +4620,7 @@ mod tests {
             hmr: false,
             paths: vec![String::from("file1"), String::from("file2")],
             no_clear_screen: false,
+            exclude: vec![],
           }),
         }),
         ..Flags::default()
@@ -4545,6 +4648,109 @@ mod tests {
             hmr: false,
             paths: vec![],
             no_clear_screen: true,
+            exclude: vec![],
+          }),
+        }),
+        ..Flags::default()
+      }
+    );
+  }
+
+  #[test]
+  fn run_watch_with_excluded_paths() {
+    let r = flags_from_vec(svec!(
+      "deno",
+      "run",
+      "--watch",
+      "--watch-exclude=foo",
+      "script.ts"
+    ));
+
+    let flags = r.unwrap();
+    assert_eq!(
+      flags,
+      Flags {
+        subcommand: DenoSubcommand::Run(RunFlags {
+          script: "script.ts".to_string(),
+          watch: Some(WatchFlagsWithPaths {
+            hmr: false,
+            paths: vec![],
+            no_clear_screen: false,
+            exclude: vec![String::from("foo")],
+          }),
+        }),
+        ..Flags::default()
+      }
+    );
+
+    let r = flags_from_vec(svec!(
+      "deno",
+      "run",
+      "--watch=foo",
+      "--watch-exclude=bar",
+      "script.ts"
+    ));
+    let flags = r.unwrap();
+    assert_eq!(
+      flags,
+      Flags {
+        subcommand: DenoSubcommand::Run(RunFlags {
+          script: "script.ts".to_string(),
+          watch: Some(WatchFlagsWithPaths {
+            hmr: false,
+            paths: vec![String::from("foo")],
+            no_clear_screen: false,
+            exclude: vec![String::from("bar")],
+          }),
+        }),
+        ..Flags::default()
+      }
+    );
+
+    let r = flags_from_vec(svec![
+      "deno",
+      "run",
+      "--watch",
+      "--watch-exclude=foo,bar",
+      "script.ts"
+    ]);
+
+    let flags = r.unwrap();
+    assert_eq!(
+      flags,
+      Flags {
+        subcommand: DenoSubcommand::Run(RunFlags {
+          script: "script.ts".to_string(),
+          watch: Some(WatchFlagsWithPaths {
+            hmr: false,
+            paths: vec![],
+            no_clear_screen: false,
+            exclude: vec![String::from("foo"), String::from("bar")],
+          }),
+        }),
+        ..Flags::default()
+      }
+    );
+
+    let r = flags_from_vec(svec![
+      "deno",
+      "run",
+      "--watch=foo,bar",
+      "--watch-exclude=baz,qux",
+      "script.ts"
+    ]);
+
+    let flags = r.unwrap();
+    assert_eq!(
+      flags,
+      Flags {
+        subcommand: DenoSubcommand::Run(RunFlags {
+          script: "script.ts".to_string(),
+          watch: Some(WatchFlagsWithPaths {
+            hmr: false,
+            paths: vec![String::from("foo"), String::from("bar")],
+            no_clear_screen: false,
+            exclude: vec![String::from("baz"), String::from("qux"),],
           }),
         }),
         ..Flags::default()
@@ -4876,6 +5082,7 @@ mod tests {
           watch: Some(WatchFlags {
             hmr: false,
             no_clear_screen: true,
+            exclude: vec![],
           })
         }),
         ext: Some("ts".to_string()),
@@ -5112,6 +5319,7 @@ mod tests {
           watch: Some(WatchFlags {
             hmr: false,
             no_clear_screen: true,
+            exclude: vec![],
           })
         }),
         ..Flags::default()
@@ -6350,6 +6558,7 @@ mod tests {
           watch: Some(WatchFlags {
             hmr: false,
             no_clear_screen: true,
+            exclude: vec![],
           }),
         }),
         type_check_mode: TypeCheckMode::Local,
@@ -7624,6 +7833,7 @@ mod tests {
           watch: Some(WatchFlags {
             hmr: false,
             no_clear_screen: true,
+            exclude: vec![],
           }),
           reporter: Default::default(),
           junit_path: None,