Re: strange case of "if ((a & b))" - Mailing list pgsql-hackers

On Wed, Aug 18, 2021 at 02:02:22PM -0400, Bruce Momjian wrote:
> On Thu, Jun 24, 2021 at 09:31:11PM -0500, Justin Pryzby wrote:
> > On Wed, Apr 28, 2021 at 02:40:09PM -0400, Tom Lane wrote:
> > > Justin Pryzby <pryzby@telsasoft.com> writes:
> > > > These look strange to me - the inner parens don't do anything.
> > > > I wouldn't write it with 2x parens for the same reason I wouldn't write it with
> > > > 8x parens.
> > > 
> > > Agreed, but shouldn't we just drop the excess parens rather than
> > > doubling down on useless notation?
> > 
> > I believe I got the impression from Michael that there was a style preference
> > to write != 0.
> > 
> > 0002 is a bonus patch I found in my typos branch.  I will hold onto it for
> > later if nobody wants to deal with it.
> 
> I am ready to deal with this patch.  Should I apply it to master soon?

Thanks for looking at it.  I suggest not to apply 0002 - I'll resend it on
another thread with other, similar cleanups.

However, I have another patch to clean up stuff like "? true : false", which
seems related to this patch (but maybe it should be applied separately).

commit 85952c0e1621a5a491a9422cdee66e733728e3a8
Author: Justin Pryzby <pryzbyj@telsasoft.com>
Date:   Fri May 7 08:16:51 2021 -0500

    Avoid verbose ternary operator with expressions which are already boolean

diff --git a/contrib/intarray/_int_tool.c b/contrib/intarray/_int_tool.c
index 91690aff51..8ed4d63fc3 100644
--- a/contrib/intarray/_int_tool.c
+++ b/contrib/intarray/_int_tool.c
@@ -41,7 +41,7 @@ inner_int_contains(ArrayType *a, ArrayType *b)
             break;                /* db[j] is not in da */
     }
 
-    return (n == nb) ? true : false;
+    return (n == nb);
 }
 
 /* arguments are assumed sorted */
diff --git a/contrib/ltree/ltree_gist.c b/contrib/ltree/ltree_gist.c
index 6cf181bc53..7c39ed4298 100644
--- a/contrib/ltree/ltree_gist.c
+++ b/contrib/ltree/ltree_gist.c
@@ -137,7 +137,7 @@ ltree_same(PG_FUNCTION_ARGS)
         PG_RETURN_POINTER(result);
 
     if (LTG_ISONENODE(a))
-        *result = (ISEQ(LTG_NODE(a), LTG_NODE(b))) ? true : false;
+        *result = ISEQ(LTG_NODE(a), LTG_NODE(b));
     else
     {
         int32        i;
diff --git a/contrib/sepgsql/selinux.c b/contrib/sepgsql/selinux.c
index f11968bcaa..dac3f3ec91 100644
--- a/contrib/sepgsql/selinux.c
+++ b/contrib/sepgsql/selinux.c
@@ -615,7 +615,7 @@ static int    sepgsql_mode = SEPGSQL_MODE_INTERNAL;
 bool
 sepgsql_is_enabled(void)
 {
-    return (sepgsql_mode != SEPGSQL_MODE_DISABLED ? true : false);
+    return sepgsql_mode != SEPGSQL_MODE_DISABLED;
 }
 
 /*
diff --git a/src/backend/access/gin/gindatapage.c b/src/backend/access/gin/gindatapage.c
index 06c0586543..2ada1dcbda 100644
--- a/src/backend/access/gin/gindatapage.c
+++ b/src/backend/access/gin/gindatapage.c
@@ -241,7 +241,7 @@ dataIsMoveRight(GinBtree btree, Page page)
     if (GinPageIsDeleted(page))
         return true;
 
-    return (ginCompareItemPointers(&btree->itemptr, iptr) > 0) ? true : false;
+    return ginCompareItemPointers(&btree->itemptr, iptr) > 0;
 }
 
 /*
diff --git a/src/backend/access/gin/ginutil.c b/src/backend/access/gin/ginutil.c
index cdd626ff0a..5b054ef4ae 100644
--- a/src/backend/access/gin/ginutil.c
+++ b/src/backend/access/gin/ginutil.c
@@ -100,7 +100,7 @@ initGinState(GinState *state, Relation index)
     MemSet(state, 0, sizeof(GinState));
 
     state->index = index;
-    state->oneCol = (origTupdesc->natts == 1) ? true : false;
+    state->oneCol = origTupdesc->natts == 1;
     state->origTupdesc = origTupdesc;
 
     for (i = 0; i < origTupdesc->natts; i++)
diff --git a/src/backend/access/gist/gist.c b/src/backend/access/gist/gist.c
index 0683f42c25..a83a2e9952 100644
--- a/src/backend/access/gist/gist.c
+++ b/src/backend/access/gist/gist.c
@@ -231,7 +231,7 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 {
     BlockNumber blkno = BufferGetBlockNumber(buffer);
     Page        page = BufferGetPage(buffer);
-    bool        is_leaf = (GistPageIsLeaf(page)) ? true : false;
+    bool        is_leaf = GistPageIsLeaf(page);
     XLogRecPtr    recptr;
     int            i;
     bool        is_split;
diff --git a/src/backend/access/gist/gistsplit.c b/src/backend/access/gist/gistsplit.c
index 526ed1218e..853ebc387b 100644
--- a/src/backend/access/gist/gistsplit.c
+++ b/src/backend/access/gist/gistsplit.c
@@ -303,9 +303,9 @@ supportSecondarySplit(Relation r, GISTSTATE *giststate, int attno,
         penalty2 = gistpenalty(giststate, attno, entry1, false, &entrySR, false);
 
         if (penalty1 < penalty2)
-            leaveOnLeft = (sv->spl_ldatum_exists) ? true : false;
+            leaveOnLeft = sv->spl_ldatum_exists;
         else
-            leaveOnLeft = (sv->spl_rdatum_exists) ? true : false;
+            leaveOnLeft = sv->spl_rdatum_exists;
     }
 
     if (leaveOnLeft == false)
diff --git a/src/backend/access/hash/hash.c b/src/backend/access/hash/hash.c
index 0752fb38a9..5e3730201c 100644
--- a/src/backend/access/hash/hash.c
+++ b/src/backend/access/hash/hash.c
@@ -816,7 +816,7 @@ hashbucketcleanup(Relation rel, Bucket cur_bucket, Buffer bucket_buf,
                 XLogRecPtr    recptr;
 
                 xlrec.clear_dead_marking = clear_dead_marking;
-                xlrec.is_primary_bucket_page = (buf == bucket_buf) ? true : false;
+                xlrec.is_primary_bucket_page = buf == bucket_buf;
 
                 XLogBeginInsert();
                 XLogRegisterData((char *) &xlrec, SizeOfHashDelete);
diff --git a/src/backend/access/hash/hashinsert.c b/src/backend/access/hash/hashinsert.c
index d254a00b6a..83af8c1f67 100644
--- a/src/backend/access/hash/hashinsert.c
+++ b/src/backend/access/hash/hashinsert.c
@@ -176,7 +176,7 @@ restart_insert:
             LockBuffer(buf, BUFFER_LOCK_UNLOCK);
 
             /* chain to a new overflow page */
-            buf = _hash_addovflpage(rel, metabuf, buf, (buf == bucket_buf) ? true : false);
+            buf = _hash_addovflpage(rel, metabuf, buf, buf == bucket_buf);
             page = BufferGetPage(buf);
 
             /* should fit now, given test above */
diff --git a/src/backend/access/hash/hashovfl.c b/src/backend/access/hash/hashovfl.c
index 404f2b6221..7397b6963f 100644
--- a/src/backend/access/hash/hashovfl.c
+++ b/src/backend/access/hash/hashovfl.c
@@ -953,7 +953,7 @@ readpage:
                         xl_hash_move_page_contents xlrec;
 
                         xlrec.ntups = nitups;
-                        xlrec.is_prim_bucket_same_wrt = (wbuf == bucket_buf) ? true : false;
+                        xlrec.is_prim_bucket_same_wrt = wbuf == bucket_buf;
 
                         XLogBeginInsert();
                         XLogRegisterData((char *) &xlrec, SizeOfHashMovePageContents);
diff --git a/src/backend/access/hash/hashpage.c b/src/backend/access/hash/hashpage.c
index b730025356..eda10386b2 100644
--- a/src/backend/access/hash/hashpage.c
+++ b/src/backend/access/hash/hashpage.c
@@ -1195,7 +1195,7 @@ _hash_splitbucket(Relation rel,
                     all_tups_size = 0;
 
                     /* chain to a new overflow page */
-                    nbuf = _hash_addovflpage(rel, metabuf, nbuf, (nbuf == bucket_nbuf) ? true : false);
+                    nbuf = _hash_addovflpage(rel, metabuf, nbuf, nbuf == bucket_nbuf);
                     npage = BufferGetPage(nbuf);
                     nopaque = (HashPageOpaque) PageGetSpecialPointer(npage);
                 }
diff --git a/src/backend/access/heap/heapam_visibility.c b/src/backend/access/heap/heapam_visibility.c
index d3c57cd16a..b72b03ea25 100644
--- a/src/backend/access/heap/heapam_visibility.c
+++ b/src/backend/access/heap/heapam_visibility.c
@@ -1475,7 +1475,7 @@ HeapTupleIsSurelyDead(HeapTuple htup, GlobalVisState *vistest)
      * all relevant hint bits were just set moments ago).
      */
     if (!HeapTupleHeaderXminCommitted(tuple))
-        return HeapTupleHeaderXminInvalid(tuple) ? true : false;
+        return HeapTupleHeaderXminInvalid(tuple);
 
     /*
      * If the inserting transaction committed, but any deleting transaction
diff --git a/src/backend/access/spgist/spgscan.c b/src/backend/access/spgist/spgscan.c
index e14b9fa573..037d56132e 100644
--- a/src/backend/access/spgist/spgscan.c
+++ b/src/backend/access/spgist/spgscan.c
@@ -860,7 +860,7 @@ redirect:
             page = BufferGetPage(buffer);
             TestForOldSnapshot(snapshot, index, page);
 
-            isnull = SpGistPageStoresNulls(page) ? true : false;
+            isnull = SpGistPageStoresNulls(page);
 
             if (SpGistPageIsLeaf(page))
             {
diff --git a/src/backend/executor/spi.c b/src/backend/executor/spi.c
index bf619d3a65..23fe1d85fd 100644
--- a/src/backend/executor/spi.c
+++ b/src/backend/executor/spi.c
@@ -1037,7 +1037,7 @@ SPI_modifytuple(Relation rel, HeapTuple tuple, int natts, int *attnum,
         if (attnum[i] <= 0 || attnum[i] > numberOfAttributes)
             break;
         v[attnum[i] - 1] = Values[i];
-        n[attnum[i] - 1] = (Nulls && Nulls[i] == 'n') ? true : false;
+        n[attnum[i] - 1] = Nulls && Nulls[i] == 'n';
     }
 
     if (i == natts)                /* no errors in *attnum */
diff --git a/src/backend/jit/jit.c b/src/backend/jit/jit.c
index 2da300e000..91b8ae6c51 100644
--- a/src/backend/jit/jit.c
+++ b/src/backend/jit/jit.c
@@ -198,7 +198,7 @@ file_exists(const char *name)
     AssertArg(name != NULL);
 
     if (stat(name, &st) == 0)
-        return S_ISDIR(st.st_mode) ? false : true;
+        return !S_ISDIR(st.st_mode);
     else if (!(errno == ENOENT || errno == ENOTDIR))
         ereport(ERROR,
                 (errcode_for_file_access(),
diff --git a/src/backend/optimizer/util/pathnode.c b/src/backend/optimizer/util/pathnode.c
index 41cbf328c4..3f14b5c1c4 100644
--- a/src/backend/optimizer/util/pathnode.c
+++ b/src/backend/optimizer/util/pathnode.c
@@ -936,7 +936,7 @@ create_seqscan_path(PlannerInfo *root, RelOptInfo *rel,
     pathnode->pathtarget = rel->reltarget;
     pathnode->param_info = get_baserel_parampathinfo(root, rel,
                                                      required_outer);
-    pathnode->parallel_aware = parallel_workers > 0 ? true : false;
+    pathnode->parallel_aware = parallel_workers > 0;
     pathnode->parallel_safe = rel->consider_parallel;
     pathnode->parallel_workers = parallel_workers;
     pathnode->pathkeys = NIL;    /* seqscan has unordered result */
@@ -1057,7 +1057,7 @@ create_bitmap_heap_path(PlannerInfo *root,
     pathnode->path.pathtarget = rel->reltarget;
     pathnode->path.param_info = get_baserel_parampathinfo(root, rel,
                                                           required_outer);
-    pathnode->path.parallel_aware = parallel_degree > 0 ? true : false;
+    pathnode->path.parallel_aware = parallel_degree > 0;
     pathnode->path.parallel_safe = rel->consider_parallel;
     pathnode->path.parallel_workers = parallel_degree;
     pathnode->path.pathkeys = NIL;    /* always unordered */
diff --git a/src/backend/statistics/mcv.c b/src/backend/statistics/mcv.c
index ef118952c7..35b39ece07 100644
--- a/src/backend/statistics/mcv.c
+++ b/src/backend/statistics/mcv.c
@@ -1772,7 +1772,7 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses,
             for (i = 0; i < mcvlist->nitems; i++)
             {
                 int            j;
-                bool        match = (expr->useOr ? false : true);
+                bool        match = !expr->useOr;
                 MCVItem    *item = &mcvlist->items[i];
 
                 /*
diff --git a/src/backend/storage/file/buffile.c b/src/backend/storage/file/buffile.c
index a4be5fe513..41a6d4793c 100644
--- a/src/backend/storage/file/buffile.c
+++ b/src/backend/storage/file/buffile.c
@@ -325,7 +325,7 @@ BufFileOpenShared(SharedFileSet *fileset, const char *name, int mode)
 
     file = makeBufFileCommon(nfiles);
     file->files = files;
-    file->readOnly = (mode == O_RDONLY) ? true : false;
+    file->readOnly = mode == O_RDONLY;
     file->fileset = fileset;
     file->name = pstrdup(name);
 
diff --git a/src/backend/tsearch/ts_parse.c b/src/backend/tsearch/ts_parse.c
index d978c8850d..3ae0044dfb 100644
--- a/src/backend/tsearch/ts_parse.c
+++ b/src/backend/tsearch/ts_parse.c
@@ -288,7 +288,7 @@ LexizeExec(LexizeData *ld, ParsedLex **correspondLexem)
                 }
             }
 
-            ld->dictState.isend = (curVal->type == 0) ? true : false;
+            ld->dictState.isend = (curVal->type == 0);
             ld->dictState.getnext = false;
 
             res = (TSLexeme *) DatumGetPointer(FunctionCall4(&(dict->lexize),
diff --git a/src/backend/utils/adt/bool.c b/src/backend/utils/adt/bool.c
index fe11d1ae94..cd98f84270 100644
--- a/src/backend/utils/adt/bool.c
+++ b/src/backend/utils/adt/bool.c
@@ -184,7 +184,7 @@ boolrecv(PG_FUNCTION_ARGS)
     int            ext;
 
     ext = pq_getmsgbyte(buf);
-    PG_RETURN_BOOL((ext != 0) ? true : false);
+    PG_RETURN_BOOL(ext != 0);
 }
 
 /*
diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index 4df8cc5abf..0f5f1208c9 100644
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -7997,14 +7997,14 @@ isSimpleNode(Node *node, Node *parentNode, int prettyFlags)
              * appears simple since . has top precedence, unless parent is
              * T_FieldSelect itself!
              */
-            return (IsA(parentNode, FieldSelect) ? false : true);
+            return !IsA(parentNode, FieldSelect);
 
         case T_FieldStore:
 
             /*
              * treat like FieldSelect (probably doesn't matter)
              */
-            return (IsA(parentNode, FieldStore) ? false : true);
+            return !IsA(parentNode, FieldStore);
 
         case T_CoerceToDomain:
             /* maybe simple, check args */
diff --git a/src/backend/utils/adt/tsquery_gist.c b/src/backend/utils/adt/tsquery_gist.c
index 14d7343afa..906a686914 100644
--- a/src/backend/utils/adt/tsquery_gist.c
+++ b/src/backend/utils/adt/tsquery_gist.c
@@ -109,7 +109,7 @@ gtsquery_same(PG_FUNCTION_ARGS)
     TSQuerySign b = PG_GETARG_TSQUERYSIGN(1);
     bool       *result = (bool *) PG_GETARG_POINTER(2);
 
-    *result = (a == b) ? true : false;
+    *result = (a == b);
 
     PG_RETURN_POINTER(result);
 }
diff --git a/src/backend/utils/adt/tsquery_util.c b/src/backend/utils/adt/tsquery_util.c
index 7f936427b5..3dcc753e98 100644
--- a/src/backend/utils/adt/tsquery_util.c
+++ b/src/backend/utils/adt/tsquery_util.c
@@ -186,7 +186,7 @@ QTNEq(QTNode *a, QTNode *b)
     if (!(sign == a->sign && sign == b->sign))
         return false;
 
-    return (QTNodeCompare(a, b) == 0) ? true : false;
+    return QTNodeCompare(a, b) == 0;
 }
 
 /*
diff --git a/src/backend/utils/adt/xid8funcs.c b/src/backend/utils/adt/xid8funcs.c
index cc2b4ac797..6c6786bc39 100644
--- a/src/backend/utils/adt/xid8funcs.c
+++ b/src/backend/utils/adt/xid8funcs.c
@@ -221,7 +221,7 @@ is_visible_fxid(FullTransactionId value, const pg_snapshot *snap)
         res = bsearch(&value, snap->xip, snap->nxip, sizeof(FullTransactionId),
                       cmp_fxid);
         /* if found, transaction is still in progress */
-        return (res) ? false : true;
+        return !res;
     }
 #endif
     else
diff --git a/src/backend/utils/fmgr/dfmgr.c b/src/backend/utils/fmgr/dfmgr.c
index e8c6cdde97..96fd9d2268 100644
--- a/src/backend/utils/fmgr/dfmgr.c
+++ b/src/backend/utils/fmgr/dfmgr.c
@@ -458,7 +458,7 @@ file_exists(const char *name)
     AssertArg(name != NULL);
 
     if (stat(name, &st) == 0)
-        return S_ISDIR(st.st_mode) ? false : true;
+        return !S_ISDIR(st.st_mode);
     else if (!(errno == ENOENT || errno == ENOTDIR || errno == EACCES))
         ereport(ERROR,
                 (errcode_for_file_access(),