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[pspp] / src / language / commands / delete-variables.c

diff --git a/src/language/commands/delete-variables.c b/src/language/commands/delete-variables.c
index 03ccd115fed7e7ae7374ad6674aba9c0c0a7baf9..b7ca748256f45aa4d36d0cbe1cc1badb91ba4678 100644 (file)
--- a/src/language/commands/delete-variables.c
+++ b/src/language/commands/delete-variables.c
@@ -33,81 +33,38 @@
 int
 cmd_delete_variables (struct lexer *lexer, struct dataset *ds)
 {
+  if (proc_has_transformations (ds))
+    {
+      lex_ofs_error (lexer, 0, lex_ofs (lexer) - 1,
+                     _("%s may not be used when there are pending "
+                       "transformations (use %s to execute transformations)."),
+                     "DELETE VARIABLES", "EXECUTE");
+      return CMD_FAILURE;
+    }
+  if (proc_in_temporary_transformations (ds))
+    {
+      lex_ofs_error (lexer, 0, lex_ofs (lexer) - 1,
+                     _("%s may not be used after %s."),
+                     "DELETE VARIABLES", "TEMPORARY");
+      return CMD_FAILURE;
+    }
+
   struct variable **vars;
   size_t n_vars;
-  bool ok;
-
-  if (proc_make_temporary_transformations_permanent (ds))
-    lex_ofs_error (lexer, 0, lex_ofs (lexer) - 1,
-                   _("%s may not be used after %s.  "
-                     "Temporary transformations will be made permanent."),
-                   "DELETE VARIABLES", "TEMPORARY");
-
   if (!parse_variables (lexer, dataset_dict (ds), &vars, &n_vars, PV_NONE))
-    goto error;
+    return CMD_FAILURE;
   if (n_vars == dict_get_n_vars (dataset_dict (ds)))
     {
       lex_ofs_error (lexer, 0, lex_ofs (lexer) - 1,
                      _("%s may not be used to delete all variables "
                        "from the active dataset dictionary.  "
                        "Use %s instead."), "DELETE VARIABLES", "NEW FILE");
-      goto error;
+      free (vars);
+      return CMD_FAILURE;
     }
 
-  ok = casereader_destroy (proc_open_filtering (ds, false));
-  ok = proc_commit (ds) && ok;
-  if (!ok)
-    goto error;
-
-  dict_delete_vars (dataset_dict (ds), vars, n_vars);
-
-  /* XXX A bunch of bugs conspire to make executing transformations again here
-     necessary, even though it shouldn't be.
-
-     Consider the following (which is included in delete-variables.at):
-
-        DATA LIST NOTABLE /s1 TO s2 1-2(A).
-        BEGIN DATA
-        12
-        END DATA.
-        DELETE VARIABLES s1.
-        NUMERIC n1.
-        LIST.
-
-     The DATA LIST gives us a caseproto with widths 1,1.  DELETE VARIABLES
-     deletes the first variable so we now have -1,1.  This already is
-     technically a problem because proc_casereader_read() calls
-     case_unshare_and_resize() from the former to the latter caseproto, and
-     these caseprotos are not conformable (which is a requirement for
-     case_resize()).  It doesn't cause an assert by default because
-     case_resize() uses expensive_assert() to check for it though.  However, in
-     practice we don't see a problem yet because case_resize() only does work
-     if the number of widths in the source and dest caseproto are different.
-
-     Executing NUMERIC adds a third variable, though, so we have -1,1,0.  This
-     makes caseproto_resize() notice that there are fewer strings in the new
-     caseproto.  Therefore it destroys the second one (s2).  It should destroy
-     the first one (s1), but if the caseprotos were really conformable then it
-     would have destroyed the right one.  This mistake eventually causes a bad
-     memory reference.
-
-     Executing transformations a second time after DELETE VARIABLES, like we do
-     below, works around the problem because we can never run into a situation
-     where we've got both new variables (triggering a resize) and deleted
-     variables (triggering the bad free).
-
-     We should fix this in a better way.  Doing it cleanly seems hard.  This
-     seems to work for now. */
-  ok = casereader_destroy (proc_open_filtering (ds, false));
-  ok = proc_commit (ds) && ok;
-  if (!ok)
-    goto error;
-
+  dataset_delete_vars (ds, vars, n_vars);
   free (vars);
 
   return CMD_SUCCESS;
-
- error:
-  free (vars);
-  return CMD_CASCADING_FAILURE;
 }