Remove bms_first_member().

This function has been semi-deprecated ever since we invented
bms_next_member().  Its habit of scribbling on the input bitmapset
isn't great, plus for sufficiently large bitmapsets it would take
O(N^2) time to complete a loop.  Now we have the additional problem
that reducing the input to empty while leaving it still accessible
would violate a planned invariant.  So let's just get rid of it,
after updating the few extant callers to use bms_next_member().

Patch by me; thanks to Nathan Bossart and Richard Guo for review.

Discussion: https://postgr.es/m/1159933.1677621588@sss.pgh.pa.us

1 files changed, 0 insertions, 42 deletions

diff --git a/src/backend/nodes/bitmapset.c b/src/backend/nodes/bitmapset.c
index 98660524ade..10dbbdddf58 100644
--- a/src/backend/nodes/bitmapset.c
+++ b/src/backend/nodes/bitmapset.c
@@ -983,48 +983,6 @@ bms_join(Bitmapset *a, Bitmapset *b)
 }
 
 /*
- * bms_first_member - find and remove first member of a set
- *
- * Returns -1 if set is empty.  NB: set is destructively modified!
- *
- * This is intended as support for iterating through the members of a set.
- * The typical pattern is
- *
- *			while ((x = bms_first_member(inputset)) >= 0)
- *				process member x;
- *
- * CAUTION: this destroys the content of "inputset".  If the set must
- * not be modified, use bms_next_member instead.
- */
-int
-bms_first_member(Bitmapset *a)
-{
-	int			nwords;
-	int			wordnum;
-
-	if (a == NULL)
-		return -1;
-	nwords = a->nwords;
-	for (wordnum = 0; wordnum < nwords; wordnum++)
-	{
-		bitmapword	w = a->words[wordnum];
-
-		if (w != 0)
-		{
-			int			result;
-
-			w = RIGHTMOST_ONE(w);
-			a->words[wordnum] &= ~w;
-
-			result = wordnum * BITS_PER_BITMAPWORD;
-			result += bmw_rightmost_one_pos(w);
-			return result;
-		}
-	}
-	return -1;
-}
-
-/*
  * bms_next_member - find next member of a set
  *
  * Returns smallest member greater than "prevbit", or -2 if there is none.