Fix internal error: bug in data stream opening logic.

Test case: txr -c '@(bind x 1)A' name

The problem here is that the specline has multiple elements,
so when processing the bind, rest(specline) isn't nil.  This
means that control passes through to horizontal matching
logic.  No data source is open yet; just before that logic
executes, open_data_source is called. However,
open_data_source refuses because @(bind) is a directive that
doesn't require data. So we end up in the internal error case,
because we a data source, and no attempt was made to open one.

The fix is for open_data_source to also check rest(specline).
It cannot skip opening the data source just because
the first_spec is a non-matching directive, according to
the non_matching_directive_table. This criterion should
only apply if it is the *only* directive, however.
A spec line with multiple items must match a line of data;
that's how the TXR language works.

* match.c (open_data_source): Add a condition for classifying
the directive as non-matching: it must be the only directive
in the line (rest(specline) must be nil).

1 files changed, 3 insertions, 2 deletions

diff --git a/match.c b/match.c
index 857e1df6..6480bd68 100644
--- a/match.c
+++ b/match.c
@@ -3902,8 +3902,9 @@ static void open_data_source(match_files_ctx *c)
     if (stringp(name)) {
       spec_bind (specline, first_spec, c->spec);
 
-      if (consp(first_spec) && (gethash(non_matching_directive_table,
-                                        first(first_spec))))
+      if (consp(first_spec) &&
+          (gethash(non_matching_directive_table, first(first_spec))) &&
+          !rest(specline))
       {
         debuglf(first_spec, lit("not opening source ~a "
                                 "since query starts with non-matching "