Make a partly-undone import retryable, and refuse a plan it cannot deliver

shopdb/core/services/wincimport.py

@@ -12,6 +12,8 @@ units, and records every change to the reversible import journal. That contract
 lives here and in the writer, not in the generic canonical-CSV importer.
 """
 
+import sqlalchemy as sa
+
 from shopdb.extensions import db
 from scripts.site_imports import journal
 from scripts.site_imports.approval import build_packet
@@ -38,7 +40,8 @@ def _plan_and_packet(export_text):
 
     plan, summary, _lookups = analyze_rows(_connection(), rows)
     packet = build_packet('winc-machine-adoption', plan, summary,
-                          winc_writer._PACKET_GROUPS)
+                          winc_writer._PACKET_GROUPS,
+                          creatable=winc_writer._CREATABLE_GROUPS)
     return plan, summary, packet
 
 
@@ -53,6 +56,11 @@ def _report(summary, packet):
                         for group, items in packet.get('needscreate', {}).items()},
         'unresolved': {group: dict(items)
                        for group, items in packet.get('unresolved', {}).items()},
+        # Carried separately from needscreate: both are "rows that do not
+        # exist", but only this one cannot be acknowledged away, and the page
+        # has to say WHY it is blocked rather than only that it is.
+        'uncreatable': {group: dict(items)
+                        for group, items in packet.get('uncreatable', {}).items()},
         'blocking': packet.get('blocking', False),
     }
 
@@ -111,8 +119,27 @@ def commit(export_text, acknowledge=None, createdby=None, planhash=None):
     return report
 
 
+IMPORT_KIND = 'winc-machine-adoption'
+
+
 def undo(batchid):
-    """Reverse an applied batch. Caller owns the transaction. Returns a dict."""
+    """Reverse an applied batch. Caller owns the transaction. Returns a dict.
+
+    Refuses a batch of another kind. The journal is a general primitive and
+    undo_batch does not filter on kind, so without this check the first other
+    importer's batches would be reversible through THIS endpoint - carrying
+    WINC's references map, which lists none of that importer's tables, so the
+    reference guard would pass on everything and the deletes would be
+    unconditional.
+    """
+    kind = _connection().execute(
+        sa.text('SELECT kind FROM importbatches WHERE batchid = :batchid'),
+        {'batchid': batchid}).scalar()
+    if kind is not None and kind != IMPORT_KIND:
+        raise WincImportError(
+            'batch %s was created by a different importer (%s) and cannot be '
+            'reversed here' % (batchid, kind))
+
     result = journal.undo_batch(_connection(), batchid,
                                 references=winc_writer._UNDO_REFERENCES)
     return {