New --paired-paths arguments in jupytext CLI #146

jupytext/cli.py

@@ -10,6 +10,7 @@
 from .jupytext import readf, reads, writef, writes
 from .formats import NOTEBOOK_EXTENSIONS, JUPYTEXT_FORMATS, check_file_version
 from .formats import long_form_one_format
+from .paired_paths import paired_paths
 from .combine import combine_inputs_with_outputs
 from .compare import test_round_trip_conversion, NotebookDifference
 from .languages import _SCRIPT_EXTENSIONS
@@ -242,6 +243,9 @@ def cli_jupytext(args=None):
                         help='One or more notebook(s). Input is read from stdin when no notebook '
                              'is provided, but then the --from field is mandatory',
                         nargs='*')
+    parser.add_argument('--paired-paths', '-p',
+                        help='Return the locations of the alternative representations for this notebook.',
+                        action='store_true')
     parser.add_argument('--pre-commit', action='store_true',
                         help="""Run Jupytext on the ipynb files in the git index.
 Create a pre-commit hook with:
@@ -282,17 +286,22 @@ def cli_jupytext(args=None):
     if args.version:
         return args
 
-    args.to = canonize_format(args.to, args.output)
-
     if args.input_format:
         args.input_format = canonize_format(args.input_format)
         if not args.notebooks and not args.output:
             args.output = '-'
 
+    if args.paired_paths:
+        if len(args.notebooks) != 1:
+            raise ValueError('--paired-paths applies to a single notebook')
+        return args
+
     if not args.input_format:
         if not args.notebooks and not args.pre_commit:
             raise ValueError('Please specificy either --from, --pre-commit or notebooks')
 
+    args.to = canonize_format(args.to, args.output)
+
     if args.update and not (args.test or args.test_strict) and args.to != 'ipynb':
         raise ValueError('--update works exclusively with --to notebook ')
 
@@ -314,6 +323,16 @@ def jupytext(args=None):
             sys.stdout.write(__version__ + '\n')
             return
 
+        if args.paired_paths:
+            main_path = args.notebooks[0]
+            nb = readf(main_path, args.input_format)
+            formats = nb.metadata.get('jupytext', {}).get('formats')
+            if formats:
+                for path, _ in paired_paths(main_path, formats):
+                    if path != main_path:
+                        sys.stdout.write(path + '\n')
+            return
+
         convert_notebook_files(nb_files=args.notebooks,
                                fmt=args.to,
                                input_format=args.input_format,

tests/test_cli.py

@@ -9,6 +9,7 @@
 from jupytext import readf, writef, writes
 from jupytext.cli import convert_notebook_files, cli_jupytext, jupytext, system
 from jupytext.compare import compare_notebooks
+from jupytext.paired_paths import paired_paths
 from .utils import list_notebooks
 
 
@@ -384,3 +385,19 @@ def test_update_metadata(py_file, tmpdir, capsys):
 
     out, err = capsys.readouterr()
     assert 'JSONDecodeError' in err
+
+
+@pytest.mark.parametrize('nb_file', list_notebooks('ipynb_py'))
+def test_paired_paths(nb_file, tmpdir, capsys):
+    tmp_ipynb = str(tmpdir.join('notebook.ipynb'))
+    nb = readf(nb_file)
+    nb.metadata.setdefault('jupytext', {})['formats'] = 'ipynb,_light.py,_percent.py:percent'
+    writef(nb, tmp_ipynb)
+
+    jupytext(['--paired-paths', tmp_ipynb])
+
+    out, err = capsys.readouterr()
+    assert not err
+
+    formats = nb.metadata.get('jupytext', {}).get('formats')
+    assert set(out.splitlines()).union([tmp_ipynb]) == set([path for path, _ in paired_paths(tmp_ipynb, formats)])