cli: reimplement "debug resolverev" as command to debug print revset

Also removed -r/--revision and the default "@" as it is a debug command.

src/commands/mod.rs

@@ -932,8 +932,7 @@ struct SupportConfigSchemaArgs {}
 #[derive(Subcommand, Clone, Debug)]
 #[command(hide = true)]
 enum DebugCommands {
-    #[command(name = "resolverev")]
-    ResolveRev(DebugResolveRevArgs),
+    Revset(DebugRevsetArgs),
     #[command(name = "workingcopy")]
     WorkingCopy(DebugWorkingCopyArgs),
     Template(DebugTemplateArgs),
@@ -943,10 +942,9 @@ enum DebugCommands {
     Operation(DebugOperationArgs),
 }
 
-/// Resolve a revision identifier to its full ID
+/// Evaluate revset to full commit IDs
 #[derive(clap::Args, Clone, Debug)]
-struct DebugResolveRevArgs {
-    #[arg(long, short, default_value = "@")]
+struct DebugRevsetArgs {
     revision: String,
 }
 
@@ -3092,11 +3090,7 @@ fn cmd_debug(
     subcommand: &DebugCommands,
 ) -> Result<(), CommandError> {
     match subcommand {
-        DebugCommands::ResolveRev(resolve_matches) => {
-            let workspace_command = command.workspace_helper(ui)?;
-            let commit = workspace_command.resolve_single_rev(&resolve_matches.revision)?;
-            writeln!(ui, "{}", commit.id().hex())?;
-        }
+        DebugCommands::Revset(args) => cmd_debug_revset(ui, command, args)?,
         DebugCommands::WorkingCopy(_wc_matches) => {
             let workspace_command = command.workspace_helper(ui)?;
             let wc = workspace_command.working_copy();
@@ -3174,6 +3168,27 @@ fn cmd_debug(
     Ok(())
 }
 
+fn cmd_debug_revset(
+    ui: &mut Ui,
+    command: &CommandHelper,
+    args: &DebugRevsetArgs,
+) -> Result<(), CommandError> {
+    let workspace_command = command.workspace_helper(ui)?;
+    let expression = workspace_command.parse_revset(&args.revision)?;
+    writeln!(ui, "-- Expression:")?;
+    writeln!(ui, "{expression:#?}")?;
+    writeln!(ui)?;
+    let revset = workspace_command.evaluate_revset(expression)?;
+    writeln!(ui, "-- Evaluated:")?;
+    writeln!(ui, "{revset:#?}")?;
+    writeln!(ui)?;
+    writeln!(ui, "-- Commit IDs:")?;
+    for commit_id in revset.iter() {
+        writeln!(ui, "{}", commit_id.hex())?;
+    }
+    Ok(())
+}
+
 fn cmd_workspace(
     ui: &mut Ui,
     command: &CommandHelper,

tests/test_debug_command.rs

@@ -19,6 +19,33 @@ use crate::common::TestEnvironment;
 
 pub mod common;
 
+#[test]
+fn test_debug_revset() {
+    let test_env = TestEnvironment::default();
+    test_env.jj_cmd_success(test_env.env_root(), &["init", "repo", "--git"]);
+    let workspace_path = test_env.env_root().join("repo");
+
+    let stdout = test_env.jj_cmd_success(&workspace_path, &["debug", "revset", "root"]);
+    insta::with_settings!({filters => vec![
+        (r"(?m)(^    .*\n)+", "    ..\n"),
+    ]}, {
+        assert_snapshot!(stdout, @r###"
+        -- Expression:
+        Symbol(
+            ..
+        )
+
+        -- Evaluated:
+        RevsetImpl {
+            ..
+        }
+
+        -- Commit IDs:
+        0000000000000000000000000000000000000000
+        "###);
+    });
+}
+
 #[test]
 fn test_debug_index() {
     let test_env = TestEnvironment::default();