Add a --skip-empty flag to rebase

CHANGELOG.md

@@ -25,6 +25,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   usual behavior where commits that became unreachable in the Git repo are
   abandoned ([#2504](https://github.com/martinvonz/jj/pull/2504)).
 
+* `jj rebase` now takes the flag `--skip-empty`, which doesn't copy over commits
+  that would become empty after a rebase.
+
 ### Fixed bugs
 
 

cli/src/commands/rebase.rs

@@ -143,6 +143,11 @@ pub(crate) struct RebaseArgs {
     /// commit)
     #[arg(long, short, required = true)]
     destination: Vec<RevisionArg>,
+
+    #[arg(long)]
+    /// If true, when rebasing would produce an empty commit, the commit is skipped.
+    skip_empty: bool,
+
     /// Deprecated. Please prefix the revset with `all:` instead.
     #[arg(long, short = 'L', hide = true)]
     allow_large_revsets: bool,
@@ -162,8 +167,10 @@ Please use `jj rebase -d 'all:x|y'` instead of `jj rebase --allow-large-revsets
     }
 
     let rebase_options = RebaseOptions {
-        // TODO: Add a command-line flag for this.
-        empty: EmptyBehaviour::Keep,
+        empty: match args.skip_empty {
+            true => EmptyBehaviour::AbandonAllEmpty,
+            false => EmptyBehaviour::Keep,
+        },
     };
     let mut workspace_command = command.workspace_helper(ui)?;
     let new_parents = cli_util::resolve_all_revs(&workspace_command, ui, &args.destination)?