feat: add generate-completions cmd., support Nushell

Author: ErichDonGubler

Cargo.lock

@@ -43,6 +43,8 @@ wax = { version = "0.6.0", features = [
 whippit = { version = "0.6.3", path = "../whippit", default-features = false, features = [
   "serde1",
 ] }
+clap_complete = "4.5.5"
+clap_complete_nushell = "4.5.2"
 
 [dev-dependencies]
 insta = { workspace = true }

moz-webgpu-cts/Cargo.toml

@@ -33,7 +33,7 @@ use std::{
 
 use crate::wpt::path::Browser;
 use camino::Utf8PathBuf;
-use clap::{Parser, ValueEnum};
+use clap::{CommandFactory, Parser, ValueEnum};
 use enumset::{EnumSet, EnumSetType};
 use indexmap::{IndexMap, IndexSet};
 use itertools::Itertools;
@@ -145,6 +145,8 @@ enum Subcommand {
     /// Dump all metadata as JSON. Do so at your own risk; no guarantees are made about the
     /// schema of this JSON, for now.
     DumpJson,
+    /// Generate completions for various supported shells.
+    GenerateCompletions { shell: CompletionShell },
 }
 
 #[derive(Clone, Debug, clap::Args)]
@@ -257,6 +259,11 @@ enum UpdateBacklogCriteria {
     },
 }
 
+#[derive(Clone, Copy, Debug, ValueEnum)]
+enum CompletionShell {
+    Nushell,
+}
+
 fn main() -> ExitCode {
     env_logger::builder()
         .filter_level(log::LevelFilter::Info)
@@ -1110,6 +1117,20 @@ fn run(cli: Cli) -> ExitCode {
                 }
             }
         }
+        Subcommand::GenerateCompletions { shell } => {
+            let generator = match shell {
+                CompletionShell::Nushell => clap_complete_nushell::Nushell,
+            };
+
+            clap_complete::generate(
+                generator,
+                &mut Cli::command(),
+                env!("CARGO_BIN_NAME"),
+                &mut io::stdout(),
+            );
+
+            ExitCode::SUCCESS
+        }
     }
 }