jj rebase -d and jj new: Allow several commits per argument with --allow-large-revsets

Eventually, we should be able to rely on `jj op restore` and the `--allow-large-revsets`.
argument should likely be removed. This is a temporary measure until we figure
out https://github.com/martinvonz/jj/issues/922 and the like.

Fixes https://github.com/martinvonz/jj/issues/571

CHANGELOG.md

@@ -120,6 +120,13 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * Command arguments to `ui.diff-editor`/`ui.merge-editor` can now be specified
   inline without referring to `[merge-tools]` table.
 
+* `jj rebase` now accepts a new `--allow-large-revsets` argument that allows the
+  revset in the `-d` argument to expand to several revisions. For example,
+  `jj rebase -s B -d B- -d C` now works even if `B` is a merge commit.
+
+* `jj new` now also accepts a `--allow-large-revsets` argument that behaves
+  similarly to `jj rebase --allow-large-revsets`.
+
 ### Fixed bugs
 
 * When sharing the working copy with a Git repo, we used to forget to export

src/cli_util.rs

@@ -1412,15 +1412,20 @@ pub fn resolve_multiple_nonempty_revsets(
 pub fn resolve_base_revs(
     workspace_command: &WorkspaceCommandHelper,
     revisions: &[RevisionArg],
+    allow_plural_revsets: bool,
 ) -> Result<IndexSet<Commit>, CommandError> {
     let mut commits = IndexSet::new();
-    for revision_str in revisions {
-        let commit = workspace_command.resolve_single_rev(revision_str)?;
-        let commit_hash = short_commit_hash(commit.id());
-        if !commits.insert(commit) {
-            return Err(user_error(format!(
-                r#"More than one revset resolved to revision {commit_hash}"#,
-            )));
+    if allow_plural_revsets {
+        commits = resolve_multiple_nonempty_revsets(revisions, workspace_command)?;
+    } else {
+        for revision_str in revisions {
+            let commit = workspace_command.resolve_single_rev(revision_str)?;
+            let commit_hash = short_commit_hash(commit.id());
+            if !commits.insert(commit) {
+                return Err(user_error(format!(
+                    r#"More than one revset resolved to revision {commit_hash}"#,
+                )));
+            }
         }
     }
 

src/commands/mod.rs

@@ -456,6 +456,9 @@ struct NewArgs {
     /// The change description to use
     #[arg(long, short, default_value = "")]
     message: DescriptionArg,
+    /// Allow revsets expanding to multiple commits in a single argument
+    #[arg(long, short = 'L')]
+    allow_large_revsets: bool,
 }
 
 /// Move changes from one revision into another
@@ -731,6 +734,9 @@ struct RebaseArgs {
     /// The revision(s) to rebase onto
     #[arg(long, short, required = true)]
     destination: Vec<RevisionArg>,
+    /// Allow revsets expanding to multiple commits in a single argument
+    #[arg(long, short = 'L')]
+    allow_large_revsets: bool,
 }
 
 /// Apply the reverse of a revision on top of another revision
@@ -1997,9 +2003,13 @@ fn cmd_new(ui: &mut Ui, command: &CommandHelper, args: &NewArgs) -> Result<(), C
         !args.revisions.is_empty(),
         "expected a non-empty list from clap"
     );
-    let commits = resolve_base_revs(&workspace_command, &args.revisions)?
-        .into_iter()
-        .collect_vec();
+    let commits = resolve_base_revs(
+        &workspace_command,
+        &args.revisions,
+        args.allow_large_revsets,
+    )?
+    .into_iter()
+    .collect_vec();
     let parent_ids = commits.iter().map(|c| c.id().clone()).collect();
     let mut tx = workspace_command.start_transaction("new empty commit");
     let merged_tree = merge_commit_trees(tx.base_repo().as_repo_ref(), &commits);
@@ -2678,7 +2688,7 @@ don't make any changes, then the operation will be aborted.
 }
 
 fn cmd_merge(ui: &mut Ui, command: &CommandHelper, args: &NewArgs) -> Result<(), CommandError> {
-    if args.revisions.len() < 2 {
+    if !args.allow_large_revsets && args.revisions.len() < 2 {
         return Err(CommandError::CliError(String::from(
             "Merge requires at least two revisions",
         )));
@@ -2688,9 +2698,13 @@ fn cmd_merge(ui: &mut Ui, command: &CommandHelper, args: &NewArgs) -> Result<(),
 
 fn cmd_rebase(ui: &mut Ui, command: &CommandHelper, args: &RebaseArgs) -> Result<(), CommandError> {
     let mut workspace_command = command.workspace_helper(ui)?;
-    let new_parents = resolve_base_revs(&workspace_command, &args.destination)?
-        .into_iter()
-        .collect_vec();
+    let new_parents = resolve_base_revs(
+        &workspace_command,
+        &args.destination,
+        args.allow_large_revsets,
+    )?
+    .into_iter()
+    .collect_vec();
     if let Some(rev_str) = &args.revision {
         rebase_revision(ui, command, &mut workspace_command, &new_parents, rev_str)?;
     } else if let Some(source_str) = &args.source {

tests/test_rebase_command.rs

@@ -321,12 +321,71 @@ fn test_rebase_multiple_destinations() {
     fe2e8e8b50b3 c
     d370aee184ba b
     "###);
+    let stdout = test_env.jj_cmd_success(
+        &repo_path,
+        &["rebase", "--allow-large-revsets", "-r", "a", "-d", "b|c"],
+    );
+    insta::assert_snapshot!(stdout, @r###""###);
+    insta::assert_snapshot!(get_log_output(&test_env, &repo_path), @r###"
+    o   a
+    |\  
+    @ | c
+    | o b
+    |/  
+    o 
+    "###);
 
     let stderr = test_env.jj_cmd_failure(&repo_path, &["rebase", "-r", "a", "-d", "b", "-d", "b"]);
     insta::assert_snapshot!(stderr, @r###"
     Error: More than one revset resolved to revision d370aee184ba
     "###);
 
+    // Adding --allow-large-revsets suppresses this error in addition to the large
+    // revsets error.
+    let stdout = test_env.jj_cmd_success(
+        &repo_path,
+        &[
+            "rebase",
+            "-r",
+            "a",
+            "-d",
+            "b",
+            "-d",
+            "b",
+            "--allow-large-revsets",
+        ],
+    );
+    insta::assert_snapshot!(stdout, @"");
+    insta::assert_snapshot!(get_log_output(&test_env, &repo_path), @r###"
+    o a
+    | @ c
+    o | b
+    |/  
+    o 
+    "###);
+    let stdout = test_env.jj_cmd_success(
+        &repo_path,
+        &[
+            "rebase",
+            "-r",
+            "a",
+            "-d",
+            "b|c",
+            "-d",
+            "b",
+            "--allow-large-revsets",
+        ],
+    );
+    insta::assert_snapshot!(stdout, @"");
+    insta::assert_snapshot!(get_log_output(&test_env, &repo_path), @r###"
+    o   a
+    |\  
+    @ | c
+    | o b
+    |/  
+    o 
+    "###);
+
     let stderr =
         test_env.jj_cmd_failure(&repo_path, &["rebase", "-r", "a", "-d", "b", "-d", "root"]);
     insta::assert_snapshot!(stderr, @r###"