fix: bring back --no-fetch flag (denoland#2671)

cli/flags.rs

@@ -96,6 +96,10 @@ fn add_run_args<'a, 'b>(app: App<'a, 'b>) -> App<'a, 'b> {
       Arg::with_name("no-prompt")
         .long("no-prompt")
         .help("Do not use prompts"),
+    ).arg(
+      Arg::with_name("no-fetch")
+        .long("no-fetch")
+        .help("Do not download remote modules"),
     ).arg(
       Arg::with_name("importmap")
         .long("importmap")
@@ -552,6 +556,9 @@ fn parse_run_args(mut flags: DenoFlags, matches: &ArgMatches) -> DenoFlags {
   if matches.is_present("no-prompt") {
     flags.no_prompts = true;
   }
+  if matches.is_present("no-fetch") {
+    flags.no_fetch = true;
+  }
   flags.import_map_path = matches.value_of("importmap").map(ToOwned::to_owned);
 
   flags
@@ -1560,4 +1567,19 @@ mod tests {
     assert_eq!(subcommand, DenoSubcommand::Run);
     assert_eq!(argv, svec!["deno", "script.ts", "-", "foo", "bar"]);
   }
+
+  #[test]
+  fn test_flags_from_vec_34() {
+    let (flags, subcommand, argv) =
+      flags_from_vec(svec!["deno", "--no-fetch", "script.ts"]);
+    assert_eq!(
+      flags,
+      DenoFlags {
+        no_fetch: true,
+        ..DenoFlags::default()
+      }
+    );
+    assert_eq!(subcommand, DenoSubcommand::Run);
+    assert_eq!(argv, svec!["deno", "script.ts"])
+  }
 }

tests/035_no_fetch_flag.out

@@ -0,0 +1 @@
+success true true true true true true true true

tests/035_no_fetch_flag.test

@@ -0,0 +1,4 @@
+# The output assumes 003_relative_import.ts has already been run earlier
+# and its output is cached to $DENO_DIR.
+args: --no-fetch http://127.0.0.1:4545/tests/019_media_types.ts
+output: tests/035_no_fetch_flag.out