Refactor pull_var_clause's API to make it less tedious to extend.

In commit 1d97c19a0f748e94 and later c1d9579dd8bf3c92, we extended
pull_var_clause's API by adding enum-type arguments.  That's sort of a pain
to maintain, though, because it means every time we add a new behavior we
must touch every last one of the call sites, even if there's a reasonable
default behavior that most of them could use.  Let's switch over to using a
bitmask of flags, instead; that seems more maintainable and might save a
nanosecond or two as well.  This commit changes no behavior in itself,
though I'm going to follow it up with one that does add a new behavior.

In passing, remove flatten_tlist(), which has not been used since 9.1
and would otherwise need the same API changes.

Removing these enums means that optimizer/tlist.h no longer needs to
depend on optimizer/var.h.  Changing that caused a number of C files to
need addition of #include "optimizer/var.h" (probably we can thank old
runs of pgrminclude for that); but on balance it seems like a good change
anyway.

1 files changed, 1 insertions, 0 deletions

diff --git a/src/backend/parser/parse_clause.c b/src/backend/parser/parse_clause.c
index 04fa1271c80..4d9febee642 100644
--- a/src/backend/parser/parse_clause.c
+++ b/src/backend/parser/parse_clause.c
@@ -28,6 +28,7 @@
 #include "nodes/makefuncs.h"
 #include "nodes/nodeFuncs.h"
 #include "optimizer/tlist.h"
+#include "optimizer/var.h"
 #include "parser/analyze.h"
 #include "parser/parsetree.h"
 #include "parser/parser.h"