v1-0001-Adjust-code-to-highlight-appendStringInfo-misusag.patch

From cf13f964c0e3b4f424c73f8bc6df603de69c8269 Mon Sep 17 00:00:00 2001
From: David Rowley <dgrowley@gmail.com>
Date: Thu, 15 Sep 2022 21:27:00 +1200
Subject: [PATCH v1] Adjust code to highlight appendStringInfo misusages

Not intended for commit
---
 src/backend/nodes/outfuncs.c | 40 ++++++++++++++++++------------------
 src/backend/utils/adt/xml.c  |  2 +-
 src/common/stringinfo.c      |  6 +++---
 src/include/lib/stringinfo.h | 30 +++++++++++++++++++++++----
 4 files changed, 50 insertions(+), 28 deletions(-)

diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index e66a99247e..a236ec9e77 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -42,92 +42,92 @@ static void outDouble(StringInfo str, double d);
 
 /* Write an integer field (anything written as ":fldname %d") */
 #define WRITE_INT_FIELD(fldname) \
-	appendStringInfo(str, " :" CppAsString(fldname) " %d", node->fldname)
+	appendStringInfoInternal(str, " :" CppAsString(fldname) " %d", node->fldname)
 
 /* Write an unsigned integer field (anything written as ":fldname %u") */
 #define WRITE_UINT_FIELD(fldname) \
-	appendStringInfo(str, " :" CppAsString(fldname) " %u", node->fldname)
+	appendStringInfoInternal(str, " :" CppAsString(fldname) " %u", node->fldname)
 
 /* Write an unsigned integer field (anything written with UINT64_FORMAT) */
 #define WRITE_UINT64_FIELD(fldname) \
-	appendStringInfo(str, " :" CppAsString(fldname) " " UINT64_FORMAT, \
+	appendStringInfoInternal(str, " :" CppAsString(fldname) " " UINT64_FORMAT, \
 					 node->fldname)
 
 /* Write an OID field (don't hard-wire assumption that OID is same as uint) */
 #define WRITE_OID_FIELD(fldname) \
-	appendStringInfo(str, " :" CppAsString(fldname) " %u", node->fldname)
+	appendStringInfoInternal(str, " :" CppAsString(fldname) " %u", node->fldname)
 
 /* Write a long-integer field */
 #define WRITE_LONG_FIELD(fldname) \
-	appendStringInfo(str, " :" CppAsString(fldname) " %ld", node->fldname)
+	appendStringInfoInternal(str, " :" CppAsString(fldname) " %ld", node->fldname)
 
 /* Write a char field (ie, one ascii character) */
 #define WRITE_CHAR_FIELD(fldname) \
-	(appendStringInfo(str, " :" CppAsString(fldname) " "), \
+	(appendStringInfoStringInternal(str, " :" CppAsString(fldname) " "), \
 	 outChar(str, node->fldname))
 
 /* Write an enumerated-type field as an integer code */
 #define WRITE_ENUM_FIELD(fldname, enumtype) \
-	appendStringInfo(str, " :" CppAsString(fldname) " %d", \
+	appendStringInfoInternal(str, " :" CppAsString(fldname) " %d", \
 					 (int) node->fldname)
 
 /* Write a float field (actually, they're double) */
 #define WRITE_FLOAT_FIELD(fldname) \
-	(appendStringInfo(str, " :" CppAsString(fldname) " "), \
+	(appendStringInfoInternal(str, " :" CppAsString(fldname) " "), \
 	 outDouble(str, node->fldname))
 
 /* Write a boolean field */
 #define WRITE_BOOL_FIELD(fldname) \
-	appendStringInfo(str, " :" CppAsString(fldname) " %s", \
+	appendStringInfoInternal(str, " :" CppAsString(fldname) " %s", \
 					 booltostr(node->fldname))
 
 /* Write a character-string (possibly NULL) field */
 #define WRITE_STRING_FIELD(fldname) \
-	(appendStringInfoString(str, " :" CppAsString(fldname) " "), \
+	(appendStringInfoStringInternal(str, " :" CppAsString(fldname) " "), \
 	 outToken(str, node->fldname))
 
 /* Write a parse location field (actually same as INT case) */
 #define WRITE_LOCATION_FIELD(fldname) \
-	appendStringInfo(str, " :" CppAsString(fldname) " %d", node->fldname)
+	appendStringInfoInternal(str, " :" CppAsString(fldname) " %d", node->fldname)
 
 /* Write a Node field */
 #define WRITE_NODE_FIELD(fldname) \
-	(appendStringInfoString(str, " :" CppAsString(fldname) " "), \
+	(appendStringInfoStringInternal(str, " :" CppAsString(fldname) " "), \
 	 outNode(str, node->fldname))
 
 /* Write a bitmapset field */
 #define WRITE_BITMAPSET_FIELD(fldname) \
-	(appendStringInfoString(str, " :" CppAsString(fldname) " "), \
+	(appendStringInfoStringInternal(str, " :" CppAsString(fldname) " "), \
 	 outBitmapset(str, node->fldname))
 
 /* Write a variable-length array (not a List) of Node pointers */
 #define WRITE_NODE_ARRAY(fldname, len) \
-	(appendStringInfoString(str, " :" CppAsString(fldname) " "), \
+	(appendStringInfoStringInternal(str, " :" CppAsString(fldname) " "), \
 	 writeNodeArray(str, (const Node * const *) node->fldname, len))
 
 /* Write a variable-length array of AttrNumber */
 #define WRITE_ATTRNUMBER_ARRAY(fldname, len) \
-	(appendStringInfoString(str, " :" CppAsString(fldname) " "), \
+	(appendStringInfoStringInternal(str, " :" CppAsString(fldname) " "), \
 	 writeAttrNumberCols(str, node->fldname, len))
 
 /* Write a variable-length array of Oid */
 #define WRITE_OID_ARRAY(fldname, len) \
-	(appendStringInfoString(str, " :" CppAsString(fldname) " "), \
+	(appendStringInfoStringInternal(str, " :" CppAsString(fldname) " "), \
 	 writeOidCols(str, node->fldname, len))
 
 /* Write a variable-length array of Index */
 #define WRITE_INDEX_ARRAY(fldname, len) \
-	(appendStringInfoString(str, " :" CppAsString(fldname) " "), \
+	(appendStringInfoStringInternal(str, " :" CppAsString(fldname) " "), \
 	 writeIndexCols(str, node->fldname, len))
 
 /* Write a variable-length array of int */
 #define WRITE_INT_ARRAY(fldname, len) \
-	(appendStringInfoString(str, " :" CppAsString(fldname) " "), \
+	(appendStringInfoStringInternal(str, " :" CppAsString(fldname) " "), \
 	 writeIntCols(str, node->fldname, len))
 
 /* Write a variable-length array of bool */
 #define WRITE_BOOL_ARRAY(fldname, len) \
-	(appendStringInfoString(str, " :" CppAsString(fldname) " "), \
+	(appendStringInfoStringInternal(str, " :" CppAsString(fldname) " "), \
 	 writeBoolCols(str, node->fldname, len))
 
 #define booltostr(x)  ((x) ? "true" : "false")
@@ -233,7 +233,7 @@ fnname(StringInfo str, const datatype *arr, int len) \
 		appendStringInfoChar(str, ')'); \
 	} \
 	else \
-		appendStringInfoString(str, "<>"); \
+		appendStringInfoStringInternal(str, "<>"); \
 }
 
 WRITE_SCALAR_ARRAY(writeAttrNumberCols, AttrNumber, " %d",)
diff --git a/src/backend/utils/adt/xml.c b/src/backend/utils/adt/xml.c
index 2300c7ebf3..9df1a5b72c 100644
--- a/src/backend/utils/adt/xml.c
+++ b/src/backend/utils/adt/xml.c
@@ -2104,7 +2104,7 @@ xml_errorHandler(void *data, xmlErrorPtr error)
 		void	   *errCtxSaved = xmlGenericErrorContext;
 
 		xmlSetGenericErrorFunc((void *) errorBuf,
-							   (xmlGenericErrorFunc) appendStringInfo);
+							   (xmlGenericErrorFunc) appendStringInfoInternal);
 
 		/* Add context information to errorBuf */
 		appendStringInfoLineSeparator(errorBuf);
diff --git a/src/common/stringinfo.c b/src/common/stringinfo.c
index 05b22b5c53..a275185113 100644
--- a/src/common/stringinfo.c
+++ b/src/common/stringinfo.c
@@ -88,7 +88,7 @@ resetStringInfo(StringInfo str)
  * strcat.
  */
 void
-appendStringInfo(StringInfo str, const char *fmt,...)
+appendStringInfoInternal(StringInfo str, const char *fmt, ...)
 {
 	int			save_errno = errno;
 
@@ -167,13 +167,13 @@ appendStringInfoVA(StringInfo str, const char *fmt, va_list args)
 }
 
 /*
- * appendStringInfoString
+ * appendStringInfoStringInternal
  *
  * Append a null-terminated string to str.
  * Like appendStringInfo(str, "%s", s) but faster.
  */
 void
-appendStringInfoString(StringInfo str, const char *s)
+appendStringInfoStringInternal(StringInfo str, const char *s)
 {
 	appendBinaryStringInfo(str, s, strlen(s));
 }
diff --git a/src/include/lib/stringinfo.h b/src/include/lib/stringinfo.h
index 36a416f8e0..4fa1b1ea66 100644
--- a/src/include/lib/stringinfo.h
+++ b/src/include/lib/stringinfo.h
@@ -93,9 +93,20 @@ extern void resetStringInfo(StringInfo str);
  * to str if necessary.  This is sort of like a combination of sprintf and
  * strcat.
  */
-extern void appendStringInfo(StringInfo str, const char *fmt,...) pg_attribute_printf(2, 3);
-
-/*------------------------
+#if defined(HAVE__BUILTIN_CONSTANT_P) && defined(USE_ASSERT_CHECKING)
+#define appendStringInfo(str, fmt, ...) \
+	do { \
+		StaticAssertStmt(!__builtin_constant_p(fmt) || strcmp(fmt, "%s") != 0,   \
+						 "use appendStringInfoString instead of appendStringInfo with %s");   \
+		appendStringInfoInternal(str, fmt, __VA_ARGS__); \
+	} while (0)
+#else
+#define appendStringInfo(str, fmt, ...) appendStringInfoInternal(str, fmt, __VA_ARGS__)
+#endif
+
+extern void appendStringInfoInternal(StringInfo str, const char *fmt,...) pg_attribute_printf(2, 3);
+
+ /*------------------------
  * appendStringInfoVA
  * Attempt to format text data under the control of fmt (an sprintf-style
  * format string) and append it to whatever is already in str.  If successful
@@ -111,7 +122,18 @@ extern int	appendStringInfoVA(StringInfo str, const char *fmt, va_list args) pg_
  * Append a null-terminated string to str.
  * Like appendStringInfo(str, "%s", s) but faster.
  */
-extern void appendStringInfoString(StringInfo str, const char *s);
+#if defined(HAVE__BUILTIN_CONSTANT_P) && defined(USE_ASSERT_CHECKING)
+#define appendStringInfoString(str, s) \
+	do { \
+		StaticAssertStmt(!__builtin_constant_p(s) || strlen(s) != 1, \
+						 "use appendStringInfoChar to append single characters to a string"); \
+		appendStringInfoStringInternal(str, s); \
+	 } while (0)
+#else
+#define appendStringInfoString(str, s) appendStringInfoStringInternal(str, s)
+#endif
+
+extern void appendStringInfoStringInternal(StringInfo str, const char *s);
 
 /*------------------------
  * appendStringInfoChar
-- 
2.40.1.windows.1