#include "data/dataset.h"
#include "data/dictionary.h"
#include "language/command.h"
+#include "language/lexer/lexer.h"
#include "language/lexer/variable-parser.h"
#include "libpspp/message.h"
cmd_delete_variables (struct lexer *lexer, struct dataset *ds)
{
struct variable **vars;
- size_t var_cnt;
+ size_t n_vars;
bool ok;
if (proc_make_temporary_transformations_permanent (ds))
- msg (SE, _("%s may not be used after %s. "
- "Temporary transformations will be made permanent."),
- "DELETE VARIABLES", "TEMPORARY");
+ 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, &var_cnt, PV_NONE))
+ if (!parse_variables (lexer, dataset_dict (ds), &vars, &n_vars, PV_NONE))
goto error;
- if (var_cnt == dict_get_var_cnt (dataset_dict (ds)))
+ if (n_vars == dict_get_n_vars (dataset_dict (ds)))
{
- msg (SE, _("%s may not be used to delete all variables "
- "from the active dataset dictionary. "
- "Use %s instead."), "DELETE VARIABLES", "NEW FILE");
+ 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;
}
ok = proc_commit (ds) && ok;
if (!ok)
goto error;
- dict_delete_vars (dataset_dict (ds), vars, var_cnt);
+
+ 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;
free (vars);