Add PackSlice JSON CLI output

Author: Jasvina

projects/packslice/README.md

@@ -36,6 +36,7 @@ packslice split examples/sample_pack examples/split_demo --group-by signature --
 packslice summarize examples/split_demo
 packslice markdown examples/split_demo examples/split_demo/REPORT.md
 packslice split examples/sample_pack examples/failure_only --group-by signature --failure-only --chronological
+packslice summarize examples/split_demo --json
 ```
 
 ## Example output
@@ -48,6 +49,12 @@ Splits:
 - train: 2 cases
 - eval: 2 cases
 - test: 2 cases
+
+$ packslice summarize examples/split_demo --json
+{
+  "group_by": "signature",
+  "total_cases": 6
+}
 ```
 
 ## CLI
@@ -56,9 +63,12 @@ Splits:
 packslice split path/to/tracepack path/to/output_dir --group-by signature --include-label status:failure
 packslice split path/to/tracepack path/to/output_dir --group-by signature --chronological --order-by source_path
 packslice summarize path/to/output_dir
+packslice split path/to/tracepack path/to/output_dir --json
 packslice markdown path/to/output_dir path/to/report.md
 ```
 
+Both `split` and `summarize` support `--json` for CI pipelines and scripted dataset workflows.
+
 ## Output layout
 
 ```text

projects/packslice/src/packslice/cli.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import argparse
+import json
 from pathlib import Path
 import sys
 
@@ -15,6 +16,14 @@ def _positive_int(value: str) -> int:
     return parsed
 
 
+def _print_json(data: dict[str, object]) -> None:
+    print(json.dumps(data, indent=2, sort_keys=True, ensure_ascii=False))
+
+
+def _add_json_flag(parser: argparse.ArgumentParser) -> None:
+    parser.add_argument("--json", action="store_true", help="print machine-readable JSON output")
+
+
 def _cmd_split(args: argparse.Namespace) -> int:
     if args.success_only and args.failure_only:
         raise SystemExit("--success-only and --failure-only cannot be used together")
@@ -28,13 +37,19 @@ def _cmd_split(args: argparse.Namespace) -> int:
         chronological=args.chronological,
         order_by=args.order_by,
     )
+    if args.json:
+        _print_json(summary)
+        return 0
     print(f"Wrote split pack to {args.output}")
     print(summarize_splits(summary))
     return 0
 
 
 def _cmd_summarize(args: argparse.Namespace) -> int:
     payload = load_summary(args.path)
+    if args.json:
+        _print_json(payload)
+        return 0
     print(summarize_splits(payload))
     return 0
 
@@ -62,10 +77,12 @@ def build_parser() -> argparse.ArgumentParser:
     split.add_argument("--train-ratio", type=_positive_int, default=70)
     split.add_argument("--eval-ratio", type=_positive_int, default=15)
     split.add_argument("--test-ratio", type=_positive_int, default=15)
+    _add_json_flag(split)
     split.set_defaults(func=_cmd_split)
 
     summarize = subparsers.add_parser("summarize", help="summarize an existing split output")
     summarize.add_argument("path")
+    _add_json_flag(summarize)
     summarize.set_defaults(func=_cmd_summarize)
 
     markdown = subparsers.add_parser("markdown", help="render a markdown report for an existing split output")

projects/packslice/tests/test_packslice.py

@@ -3,8 +3,11 @@
 import json
 import tempfile
 import unittest
+from contextlib import redirect_stdout
+from io import StringIO
 from pathlib import Path
 
+from packslice.cli import main as cli_main
 from packslice.report import markdown_splits, summarize_splits
 from packslice.splitter import split_pack
 
@@ -138,6 +141,35 @@ def test_chronological_split_keeps_ordered_groups(self):
                 ["assert-b", "billing-b"],
             )
 
+    def test_split_cli_can_emit_json(self):
+        with tempfile.TemporaryDirectory() as tmpdir:
+            root = Path(tmpdir) / "sample_pack"
+            root.mkdir()
+            self._write_pack(root)
+            out = Path(tmpdir) / "splits"
+            output = StringIO()
+            with redirect_stdout(output):
+                code = cli_main(["split", str(root), str(out), "--group-by", "signature", "--json"])
+        payload = json.loads(output.getvalue())
+        self.assertEqual(code, 0)
+        self.assertEqual(payload["total_cases"], 6)
+        self.assertEqual(payload["splits"][0]["name"], "train")
+
+    def test_summarize_cli_can_emit_json(self):
+        with tempfile.TemporaryDirectory() as tmpdir:
+            root = Path(tmpdir) / "sample_pack"
+            root.mkdir()
+            self._write_pack(root)
+            out = Path(tmpdir) / "splits"
+            split_pack(root, out, ratios=(2, 1, 1))
+            output = StringIO()
+            with redirect_stdout(output):
+                code = cli_main(["summarize", str(out), "--json"])
+        payload = json.loads(output.getvalue())
+        self.assertEqual(code, 0)
+        self.assertEqual(payload["group_by"], "signature")
+        self.assertEqual(payload["total_cases"], 6)
+
 
 if __name__ == "__main__":
     unittest.main()