Rename xdiff to diff, add --summary flag for hash/file changes

The diff command now shows actual content differences by default.
Use -s/--summary to see which files changed with hashes (previous
diff behavior).

Changes:
- Rename xdiff command to diff
- Add -s/--summary flag for metadata/hash view
- Change -s (shell-executable) to -e
- Remove old diff command (now covered by -s/--summary)
- Update tests and rename test_xdiff.py to test_diff.py

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: Ubuntu

dvx/cli/main.py

@@ -420,32 +420,6 @@ def commit_cmd(ctx, targets, force, with_deps, recursive):
         )
 
 
-@cli.command("diff")
-@click.argument("a_rev", required=False)
-@click.argument("b_rev", required=False)
-@click.option("--targets", "-t", multiple=True, help="Specific targets to diff.")
-@click.option("--json", "as_json", is_flag=True, help="Output as JSON.")
-@click.option("--md", "as_md", is_flag=True, help="Output as Markdown.")
-@click.option("--hide-missing", is_flag=True, help="Hide missing entries.")
-@click.pass_context
-def diff_cmd(ctx, a_rev, b_rev, targets, as_json, as_md, hide_missing):
-    """Show changes between commits or cache and workspace."""
-    from dvx.repo import Repo
-    from dvx.ui import ui
-    from dvx.compare import show_diff
-
-    os.chdir(ctx.obj.cd)
-    repo = Repo(_wait_for_lock=ctx.obj.wait_for_lock)
-    with repo:
-        diff_result = repo.diff(a_rev, b_rev, targets=targets or None)
-
-    if as_json:
-        ui.write_json(diff_result)
-    elif as_md:
-        from dvx.compare import show_md
-        show_md(diff_result)
-    else:
-        show_diff(diff_result, hide_missing=hide_missing)
 
 
 @cli.command("gc")
@@ -786,9 +760,9 @@ def remote_list_cmd(ctx, global_, system, local):
         ui.write(f"{name}\t{url}")
 
 
-# Register the xdiff command from content_diff module
-from dvx.commands.content_diff import xdiff
-cli.add_command(xdiff)
+# Register the diff command from content_diff module
+from dvx.commands.content_diff import diff
+cli.add_command(diff)
 
 
 def main(argv=None):

dvx/commands/content_diff.py

@@ -180,56 +180,103 @@ def _diff_directory(path1, path2, data_path, after):
     return 1 if has_diff else 0
 
 
-@click.command("xdiff", no_args_is_help=True)
+def _show_summary(ctx, refspec, ref, targets):
+    """Show summary of file/hash changes (like old dvx diff)."""
+    from dvx.repo import Repo
+    from dvx.commands.diff import CmdDiff
+
+    # Parse refspec
+    if refspec and ref:
+        raise click.UsageError("Specify -r/--refspec or -R/--ref, not both")
+
+    if ref:
+        # -R <ref> means compare <ref>^ to <ref>
+        a_rev = f"{ref}^"
+        b_rev = ref
+    elif refspec and ".." in refspec:
+        a_rev, b_rev = refspec.split("..", 1)
+    elif refspec:
+        a_rev = refspec
+        b_rev = None
+    else:
+        a_rev = None
+        b_rev = None
+
+    try:
+        repo = Repo()
+    except Exception as e:
+        raise click.ClickException(f"Not a DVX repository: {e}")
+
+    with repo:
+        diff_result = repo.diff(a_rev, b_rev, targets=targets or None)
+
+    CmdDiff._show_diff(diff_result)
+    ctx.exit(0)
+
+
+@click.command("diff")
 @click.option("-b", "--both", is_flag=True, help="Merge stderr into stdout in pipeline commands.")
 @click.option("-c/-C", "--color/--no-color", default=None, help="Force or prevent colorized output.")
 @click.option("-r", "--refspec", help="<commit1>..<commit2> or <commit> (compare to worktree).")
 @click.option("-R", "--ref", help="Shorthand for -r <ref>^..<ref> (compare commit to parent).")
-@click.option("-s", "--shell-executable", help="Shell to use for executing commands.")
+@click.option("-e", "--shell-executable", help="Shell to use for executing commands.")
 @click.option("-S", "--no-shell", is_flag=True, help="Don't use shell for subprocess execution.")
+@click.option("-s", "--summary", is_flag=True, help="Show summary of changes (files and hashes) instead of content diff.")
 @click.option("-U", "--unified", type=int, help="Number of lines of context.")
 @click.option("-v", "--verbose", is_flag=True, help="Log intermediate commands to stderr.")
 @click.option("-w", "--ignore-whitespace", is_flag=True, help="Ignore whitespace differences.")
 @click.option("-x", "--exec-cmd", "exec_cmds", multiple=True, help="Command to execute before diffing.")
 @click.argument("args", nargs=-1, metavar="[cmd...] <path>")
 @click.pass_context
-def xdiff(
+def diff(
     ctx,
     both: bool,
     color: Optional[bool],
     refspec: Optional[str],
     ref: Optional[str],
     shell_executable: Optional[str],
     no_shell: bool,
+    summary: bool,
     unified: Optional[int],
     verbose: bool,
     ignore_whitespace: bool,
     exec_cmds: Tuple[str, ...],
     args: Tuple[str, ...],
 ):
-    """Diff a DVC-tracked file between commits, optionally through preprocessing commands.
+    """Diff DVC-tracked files between commits.
+
+    By default, shows actual content differences. Use -s/--summary to show
+    a summary of which files changed (with hashes) instead.
 
     Examples:
 
     \b
-      dvx xdiff -r HEAD^..HEAD wc -l foo.dvc
-        Compare line count of foo at previous vs current commit.
+      dvx diff data.csv
+        Show content diff of data.csv between HEAD and worktree.
 
     \b
-      dvx xdiff md5sum foo
-        Diff md5sum of foo at HEAD vs current worktree.
+      dvx diff -r HEAD^..HEAD data.csv
+        Show content diff between previous and current commit.
 
     \b
-      dvx xdiff -R abc123 cat data.csv
-        Show what changed in data.csv at commit abc123.
+      dvx diff -s
+        Show summary of all changed files with hashes.
+
+    \b
+      dvx diff -R abc123 wc -l data.csv
+        Compare line count of data.csv at commit abc123 vs its parent.
     """
     from dvx.repo import Repo
 
+    # Handle summary mode (shows file/hash changes, not content)
+    if summary:
+        return _show_summary(ctx, refspec, ref, args)
+
     # Combine exec_cmds and args
     remaining = list(exec_cmds) + list(args)
 
     if not remaining:
-        raise click.UsageError("Must specify [cmd...] <path>")
+        raise click.UsageError("Must specify [cmd...] <path> (or use -s/--summary)")
 
     *cmds, target = remaining
     data_path, dvc_path = _normalize_path(target)