Add initial cell identifiers awareness

nbdime/args.py

@@ -322,6 +322,10 @@ def add_diff_args(parser):
         '-m', '--metadata',
         action=IgnorableAction,
         help="process/ignore metadata.")
+    ignorables.add_argument(
+        '-i', '--id',
+        action=IgnorableAction,
+        help="process/ignore identifiers.")
     ignorables.add_argument(
         '-d', '--details',
         action=IgnorableAction,
@@ -392,7 +396,7 @@ def process_diff_flags(args):
         # Note: This will blow away any options set via config (for these fields)
         set_notebook_diff_targets(
             args.sources, args.outputs, args.attachments, args.metadata,
-            args.details)
+            args.id, args.details)
 
 
 def resolve_diff_args(args):

nbdime/config.py

@@ -187,6 +187,12 @@ class _Ignorables(NbdimeConfigurable):
         help="process/ignore metadata.",
     ).tag(config=True)
 
+    id = Bool(
+        None,
+        allow_none=True,
+        help="process/ignore identifiers.",
+    ).tag(config=True)
+
     attachments = Bool(
         None,
         allow_none=True,

nbdime/diffing/notebooks.py

@@ -574,14 +574,15 @@ def set_notebook_diff_ignores(ignore_paths):
 
 
 def set_notebook_diff_targets(sources=True, outputs=True, attachments=True,
-                              metadata=True, details=True):
+                              metadata=True, identifier=True, details=True):
     """Configure the notebook differs to include/ignore various changes."""
 
     config = {
         '/cells/*/source': not sources,
         '/cells/*/outputs': not outputs,
         '/cells/*/attachments': not attachments,
         '/metadata': not metadata,
+        '/cells/*/id': not identifier,
         '/cells/*/metadata': not metadata,
         '/cells/*/outputs/*/metadata': not metadata,
         '/cells/*': False if details else ('execution_count',),

nbdime/ignorables.py

@@ -5,4 +5,4 @@
 
 from __future__ import unicode_literals
 
-diff_ignorables = ('sources', 'outputs', 'attachments', 'metadata', 'details')
+diff_ignorables = ('sources', 'outputs', 'attachments', 'metadata', 'id', 'details')

nbdime/merging/decisions.py

@@ -628,7 +628,7 @@ def apply_decisions(base, decisions):
             else:
                 if md.action == "clear_all":
                     clear_all_flag = True
-                    # Clear any exisiting decisions!
+                    # Clear any existing decisions!
                     diffs = []
                 ad = resolve_action(resolved, md)
                 if line:

nbdime/merging/generic.py

@@ -13,7 +13,7 @@
 from .chunks import make_merge_chunks, chunk_typename
 from .strategies import (
     resolve_strategy_generic,
-     resolve_conflicted_decisions_dict,
+    resolve_conflicted_decisions_dict,
     resolve_conflicted_decisions_list,
     resolve_conflicted_decisions_strings,
     resolve_strategy_inline_source,

nbdime/merging/notebooks.py

@@ -58,6 +58,7 @@
 
 def notebook_merge_strategies(args):
     strategies = Strategies({
+        "/cells/*/id": "remove",
         # These fields should never conflict, that would be an internal error:
         "/nbformat": "fail",
         "/cells/*/cell_type": "fail",

nbdime/merging/strategies.py

@@ -589,6 +589,12 @@ def resolve_strategy_inline_recurse(path, base, decisions):
                     "remote_metadata": rcell[k],
                 }
 
+            elif k == 'id':
+                cell[k] = {
+                    "local_id": lcell[k],
+                    "remote_id": rcell[k],
+                }
+
             elif k == 'execution_count':
                 cell[k] = None  # Clear
 

nbdime/nbshowapp.py

@@ -91,6 +91,10 @@ def _build_arg_parser():
         '-m', '--metadata',
         action=IgnorableAction,
         help="show/ignore metadata.")
+    ignorables.add_argument(
+        '-i', '--id',
+        action=IgnorableAction,
+        help="show/ignore identifiers.")
     ignorables.add_argument(
         '-d', '--details',
         action=IgnorableAction,

nbdime/prettyprint.py

@@ -112,6 +112,8 @@ def should_ignore_path(self, path):
             return not self.attachments
         if starred.startswith('/cells/*/metadata') or starred.startswith('/metadata'):
             return not self.metadata
+        if starred.startswith('/cells/*/id'):
+            return not self.id
         if starred.startswith('/cells/*/outputs'):
             return (
                 not self.outputs or
@@ -699,7 +701,7 @@ def c():
 
     exclude_keys = {
         'cell_type', 'source', 'execution_count', 'outputs', 'metadata',
-        'attachment',
+        'id', 'attachment',
     }
     if (set(cell) - exclude_keys) and config.details:
         # present anything we haven't special-cased yet (future-proofing)

nbdime/tests/test_cli_apps.py

@@ -58,7 +58,7 @@ def test_nbshow_app(filespath, capsys):
     args = nbshowapp._build_arg_parser().parse_args([afn, '--log-level=CRITICAL'])
     process_exclusive_ignorables(
         args,
-        ('sources', 'outputs', 'attachments', 'metadata', 'details'))
+        ('sources', 'outputs', 'attachments', 'metadata', 'id', 'details'))
     assert 0 == main_show(args)
     assert args.log_level == 'CRITICAL'
     assert nbdime.log.logger.level == logging.CRITICAL