Fix some -Wcast-qual warnings

Small rearrangements to avoid having to cast away qualifiers.  In some
cases, the whole cast was unnecessary.

Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>
Discussion: https://www.postgresql.org/message-id/flat/459217ca-3840-4452-8cd1-8f9b47e8d479%40eisentraut.org

contrib/btree_gist/btree_bit.c

@@ -98,7 +98,7 @@ gbt_bitcmp(const void *a, const void *b, Oid collation, FmgrInfo *flinfo)
  * descend to that leaf page.
  */
 static bytea *
-gbt_bit_xfrm(VarBit *leaf)
+gbt_bit_xfrm(const VarBit *leaf)
 {
 	bytea	   *out;
 	int			sz = VARBITBYTES(leaf) + VARHDRSZ;
@@ -125,7 +125,7 @@ gbt_bit_l2n(GBT_VARKEY *leaf, FmgrInfo *flinfo)
 	GBT_VARKEY_R r = gbt_var_key_readable(leaf);
 	bytea	   *o;
 
-	o = gbt_bit_xfrm((VarBit *) r.lower);
+	o = gbt_bit_xfrm((const VarBit *) r.lower);
 	r.upper = r.lower = o;
 	out = gbt_var_key_copy(&r);
 	pfree(o);

contrib/btree_gist/btree_utils_var.c

@@ -62,9 +62,9 @@ gbt_var_key_readable(const GBT_VARKEY *k)
 {
 	GBT_VARKEY_R r;
 
-	r.lower = (bytea *) &(((char *) k)[VARHDRSZ]);
+	r.lower = (const bytea *) &(((const char *) k)[VARHDRSZ]);
 	if (VARSIZE(k) > (VARHDRSZ + (VARSIZE(r.lower))))
-		r.upper = (bytea *) &(((char *) k)[VARHDRSZ + INTALIGN(VARSIZE(r.lower))]);
+		r.upper = (const bytea *) &(((const char *) k)[VARHDRSZ + INTALIGN(VARSIZE(r.lower))]);
 	else
 		r.upper = r.lower;
 	return r;

contrib/btree_gist/btree_utils_var.h

@@ -26,7 +26,7 @@ typedef bytea GBT_VARKEY;
  */
 typedef struct
 {
-	bytea	   *lower,
+	const bytea *lower,
 			   *upper;
 } GBT_VARKEY_R;
 

contrib/postgres_fdw/connection.c

@@ -580,28 +580,31 @@ construct_connection_params(ForeignServer *server, UserMapping *user,
 	if (MyProcPort != NULL && MyProcPort->has_scram_keys && UseScramPassthrough(server, user))
 	{
 		int			len;
+		char	   *encoded;
 		int			encoded_len;
 
 		keywords[n] = "scram_client_key";
 		len = pg_b64_enc_len(sizeof(MyProcPort->scram_ClientKey));
 		/* don't forget the zero-terminator */
-		values[n] = palloc0(len + 1);
+		encoded = palloc0(len + 1);
 		encoded_len = pg_b64_encode(MyProcPort->scram_ClientKey,
 									sizeof(MyProcPort->scram_ClientKey),
-									(char *) values[n], len);
+									encoded, len);
 		if (encoded_len < 0)
 			elog(ERROR, "could not encode SCRAM client key");
+		values[n] = encoded;
 		n++;
 
 		keywords[n] = "scram_server_key";
 		len = pg_b64_enc_len(sizeof(MyProcPort->scram_ServerKey));
 		/* don't forget the zero-terminator */
-		values[n] = palloc0(len + 1);
+		encoded = palloc0(len + 1);
 		encoded_len = pg_b64_encode(MyProcPort->scram_ServerKey,
 									sizeof(MyProcPort->scram_ServerKey),
-									(char *) values[n], len);
+									encoded, len);
 		if (encoded_len < 0)
 			elog(ERROR, "could not encode SCRAM server key");
+		values[n] = encoded;
 		n++;
 
 		/*

contrib/xml2/xslt_proc.c

@@ -60,7 +60,7 @@ xslt_process(PG_FUNCTION_ARGS)
 	volatile xsltSecurityPrefsPtr xslt_sec_prefs = NULL;
 	volatile xsltTransformContextPtr xslt_ctxt = NULL;
 	volatile int resstat = -1;
-	xmlChar    *volatile resstr = NULL;
+	xmlChar    *volatile resstrv = NULL;
 
 	if (fcinfo->nargs == 3)
 	{
@@ -80,6 +80,7 @@ xslt_process(PG_FUNCTION_ARGS)
 	PG_TRY();
 	{
 		bool		xslt_sec_prefs_error;
+		xmlChar    *resstr = NULL;
 		int			reslen = 0;
 
 		/* Parse document */
@@ -147,8 +148,8 @@ xslt_process(PG_FUNCTION_ARGS)
 			xml_ereport(xmlerrcxt, ERROR, ERRCODE_INVALID_ARGUMENT_FOR_XQUERY,
 						"failed to apply stylesheet");
 
-		resstat = xsltSaveResultToString((xmlChar **) &resstr, &reslen,
-										 restree, stylesheet);
+		resstat = xsltSaveResultToString(&resstr, &reslen, restree, stylesheet);
+		resstrv = resstr;
 
 		if (resstat >= 0)
 		{
@@ -176,8 +177,8 @@ xslt_process(PG_FUNCTION_ARGS)
 			xmlFreeDoc(ssdoc);
 		if (doctree != NULL)
 			xmlFreeDoc(doctree);
-		if (resstr != NULL)
-			xmlFree(resstr);
+		if (resstrv != NULL)
+			xmlFree(resstrv);
 		xsltCleanupGlobals();
 
 		pg_xml_done(xmlerrcxt, true);
@@ -193,8 +194,8 @@ xslt_process(PG_FUNCTION_ARGS)
 	xmlFreeDoc(doctree);
 	xsltCleanupGlobals();
 
-	if (resstr)
-		xmlFree(resstr);
+	if (resstrv)
+		xmlFree(resstrv);
 
 	pg_xml_done(xmlerrcxt, false);
 

src/backend/utils/adt/multirangetypes.c

@@ -722,11 +722,11 @@ multirange_get_range(TypeCacheEntry *rangetyp,
 	 * exact size.
 	 */
 	if (RANGE_HAS_LBOUND(flags))
-		ptr = (char *) att_addlength_pointer(ptr, typlen, ptr);
+		ptr = att_addlength_pointer(ptr, typlen, ptr);
 	if (RANGE_HAS_UBOUND(flags))
 	{
 		ptr = (char *) att_align_pointer(ptr, typalign, typlen, ptr);
-		ptr = (char *) att_addlength_pointer(ptr, typlen, ptr);
+		ptr = att_addlength_pointer(ptr, typlen, ptr);
 	}
 	len = (ptr - begin) + sizeof(RangeType) + sizeof(uint8);
 
@@ -773,7 +773,7 @@ multirange_get_bounds(TypeCacheEntry *rangetyp,
 	{
 		/* att_align_pointer cannot be necessary here */
 		lbound = fetch_att(ptr, typbyval, typlen);
-		ptr = (char *) att_addlength_pointer(ptr, typlen, ptr);
+		ptr = att_addlength_pointer(ptr, typlen, ptr);
 	}
 	else
 		lbound = (Datum) 0;

src/backend/utils/adt/rangetypes.c

@@ -2117,7 +2117,7 @@ range_deserialize(TypeCacheEntry *typcache, const RangeType *range,
 	{
 		/* att_align_pointer cannot be necessary here */
 		lbound = fetch_att(ptr, typbyval, typlen);
-		ptr = (char *) att_addlength_pointer(ptr, typlen, ptr);
+		ptr = att_addlength_pointer(ptr, typlen, ptr);
 	}
 	else
 		lbound = (Datum) 0;

src/backend/utils/adt/varlena.c

@@ -1153,9 +1153,9 @@ text_position_next_internal(char *start_ptr, TextPositionState *state)
 	int			needle_len = state->len2;
 	int			skiptablemask = state->skiptablemask;
 	const char *haystack = state->str1;
-	const char *needle = state->str2;
+	char	   *needle = state->str2;
 	const char *haystack_end = &haystack[haystack_len];
-	const char *hptr;
+	char	   *hptr;
 
 	Assert(start_ptr >= haystack && start_ptr <= haystack_end);
 	Assert(needle_len > 0);
@@ -1184,7 +1184,7 @@ text_position_next_internal(char *start_ptr, TextPositionState *state)
 		 * collation would accept an empty match, returning one would send
 		 * callers that search for successive matches into an infinite loop.)
 		 */
-		const char *result_hptr = NULL;
+		char	   *result_hptr = NULL;
 
 		hptr = start_ptr;
 		while (hptr < haystack_end)
@@ -1198,7 +1198,7 @@ text_position_next_internal(char *start_ptr, TextPositionState *state)
 			if (!state->greedy &&
 				haystack_end - hptr >= needle_len &&
 				pg_strncoll(hptr, needle_len, needle, needle_len, state->locale) == 0)
-				return (char *) hptr;
+				return hptr;
 
 			/*
 			 * Else check if any of the non-empty substrings starting at hptr
@@ -1223,7 +1223,7 @@ text_position_next_internal(char *start_ptr, TextPositionState *state)
 			hptr += pg_mblen_range(hptr, haystack_end);
 		}
 
-		return (char *) result_hptr;
+		return result_hptr;
 	}
 	else if (needle_len == 1)
 	{
@@ -1234,21 +1234,21 @@ text_position_next_internal(char *start_ptr, TextPositionState *state)
 		while (hptr < haystack_end)
 		{
 			if (*hptr == nchar)
-				return (char *) hptr;
+				return hptr;
 			hptr++;
 		}
 	}
 	else
 	{
-		const char *needle_last = &needle[needle_len - 1];
+		char	   *needle_last = &needle[needle_len - 1];
 
 		/* Start at startpos plus the length of the needle */
 		hptr = start_ptr + needle_len - 1;
 		while (hptr < haystack_end)
 		{
 			/* Match the needle scanning *backward* */
-			const char *nptr;
-			const char *p;
+			char	   *nptr;
+			char	   *p;
 
 			nptr = needle_last;
 			p = hptr;
@@ -1256,7 +1256,7 @@ text_position_next_internal(char *start_ptr, TextPositionState *state)
 			{
 				/* Matched it all?	If so, return 1-based position */
 				if (nptr == needle)
-					return (char *) p;
+					return p;
 				nptr--, p--;
 			}
 
@@ -4470,7 +4470,7 @@ string_agg_deserialize(PG_FUNCTION_ARGS)
 	bytea	   *sstate;
 	StringInfo	result;
 	StringInfoData buf;
-	char	   *data;
+	const char *data;
 	int			datalen;
 
 	/* cannot be called directly because of internal-type argument */
@@ -4492,7 +4492,7 @@ string_agg_deserialize(PG_FUNCTION_ARGS)
 
 	/* data */
 	datalen = VARSIZE_ANY_EXHDR(sstate) - 4;
-	data = (char *) pq_getmsgbytes(&buf, datalen);
+	data = pq_getmsgbytes(&buf, datalen);
 	appendBinaryStringInfo(result, data, datalen);
 
 	pq_getmsgend(&buf);

src/include/storage/bufpage.h

@@ -364,7 +364,7 @@ PageValidateSpecialPointer(const PageData *page)
 #define PageGetSpecialPointer(page) \
 ( \
 	PageValidateSpecialPointer(page), \
-	((page) + ((PageHeader) (page))->pd_special) \
+	((page) + ((const PageHeaderData *) (page))->pd_special) \
 )
 
 /*

src/test/modules/test_custom_stats/test_custom_var_stats.c

@@ -237,7 +237,7 @@ test_custom_stats_var_to_serialized_data(const PgStat_HashKey *key,
 	 * be cross-checked with the key read from main stats file at loading
 	 * time.
 	 */
-	if (!write_chunk_s(fd_description, (PgStat_HashKey *) key))
+	if (!write_chunk_s(fd_description, key))
 		return false;
 	fd_description_offset += sizeof(PgStat_HashKey);