Make postgres.bki use the same literal-string syntax as postgresql.conf.

The BKI file's string quoting conventions were previously quite weird,
perhaps as a result of repurposing a function built to scan
single-quoted strings to scan double-quoted ones.  Change to use the
same rules as we use in GUC files, allowing some simplifications in
genbki.pl and initdb.c.

While at it, completely remove the backend's scanstr() function, which
was essentially a duplicate of the string dequoting code in guc-file.l.
Instead export that one (under a less generic name than it had) and let
bootscanner.l use it.  Now we can clarify that scansup.c exists only to
support the main lexer. We could alternatively have removed GUC_scanstr,
but this way seems better since the previous arrangement could mislead
a reader into thinking that scanstr() had something to do with the main
lexer's handling of string literals.  Maybe it did once, but if so it
was a long time ago.

This patch does not bump catversion, since the initially-installed
catalog contents don't change.  Note however that successful initdb
after applying this patch will require up-to-date postgres.bki as well
as postgres and initdb executables.

In passing, remove a bunch of very-long-obsolete #include's in
bootparse.y and bootscanner.l.

John Naylor

Discussion: https://postgr.es/m/CACPNZCtDpd18T0KATTmCggO2GdVC4ow86ypiq5ENff1VnauL8g@mail.gmail.com

Author: tglsfdc

doc/src/sgml/bki.sgml

@@ -752,8 +752,8 @@ $ perl  rewrite_dat_with_prokind.pl  pg_proc.dat
    next token that syntactically cannot belong to the preceding
    command starts a new one.  (Usually you would put a new command on
    a new line, for clarity.)  Tokens can be certain key words, special
-   characters (parentheses, commas, etc.), numbers, or double-quoted
-   strings.  Everything is case sensitive.
+   characters (parentheses, commas, etc.), identifiers, numbers, or
+   single-quoted strings.  Everything is case sensitive.
   </para>
 
   <para>
@@ -876,7 +876,9 @@ $ perl  rewrite_dat_with_prokind.pl  pg_proc.dat
      <para>
       NULL values can be specified using the special key word
       <literal>_null_</literal>.  Values that do not look like
-      identifiers or digit strings must be double quoted.
+      identifiers or digit strings must be single-quoted.
+      (To include a single quote in a value, write it twice.
+      Escape-string-style backslash escapes are allowed in the string, too.)
      </para>
     </listitem>
    </varlistentry>
@@ -1046,7 +1048,7 @@ $ perl  rewrite_dat_with_prokind.pl  pg_proc.dat
 <programlisting>
 create test_table 420 (oid = oid, cola = int4, colb = text)
 open test_table
-insert ( 421 1 "value1" )
+insert ( 421 1 'value 1' )
 insert ( 422 2 _null_ )
 close test_table
 </programlisting>

src/backend/bootstrap/bootparse.y

@@ -18,16 +18,10 @@
 
 #include <unistd.h>
 
-#include "access/attnum.h"
-#include "access/htup.h"
-#include "access/itup.h"
-#include "access/tupdesc.h"
 #include "bootstrap/bootstrap.h"
-#include "catalog/catalog.h"
 #include "catalog/heap.h"
 #include "catalog/namespace.h"
 #include "catalog/pg_am.h"
-#include "catalog/pg_attribute.h"
 #include "catalog/pg_authid.h"
 #include "catalog/pg_class.h"
 #include "catalog/pg_namespace.h"
@@ -36,20 +30,7 @@
 #include "commands/defrem.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
-#include "nodes/nodes.h"
-#include "nodes/parsenodes.h"
-#include "nodes/pg_list.h"
-#include "nodes/primnodes.h"
-#include "rewrite/prs2lock.h"
-#include "storage/block.h"
-#include "storage/fd.h"
-#include "storage/ipc.h"
-#include "storage/itemptr.h"
-#include "storage/off.h"
-#include "storage/smgr.h"
-#include "tcop/dest.h"
 #include "utils/memutils.h"
-#include "utils/rel.h"
 
 
 /*

src/backend/bootstrap/bootscanner.l

@@ -15,25 +15,8 @@
  */
 #include "postgres.h"
 
-#include "access/attnum.h"
-#include "access/htup.h"
-#include "access/itup.h"
-#include "access/tupdesc.h"
 #include "bootstrap/bootstrap.h"
-#include "catalog/pg_am.h"
-#include "catalog/pg_attribute.h"
-#include "catalog/pg_class.h"
-#include "nodes/nodes.h"
-#include "nodes/parsenodes.h"
-#include "nodes/pg_list.h"
-#include "nodes/primnodes.h"
-#include "parser/scansup.h"
-#include "rewrite/prs2lock.h"
-#include "storage/block.h"
-#include "storage/fd.h"
-#include "storage/itemptr.h"
-#include "storage/off.h"
-#include "utils/rel.h"
+#include "utils/guc.h"
 
 /* Not needed now that this file is compiled as part of bootparse. */
 /* #include "bootparse.h" */
@@ -66,7 +49,7 @@ static int	yyline = 1;			/* line number for error reporting */
 
 
 id		[-A-Za-z0-9_]+
-sid		\"([^\"])*\"
+sid		\'([^']|\'\')*\'
 
 /*
  * Keyword tokens return the keyword text (as a constant string) in yylval.kw,
@@ -120,14 +103,12 @@ NOT				{ yylval.kw = "NOT"; return XNOT; }
 NULL			{ yylval.kw = "NULL"; return XNULL; }
 
 {id}			{
-					yylval.str = scanstr(yytext);
+					yylval.str = pstrdup(yytext);
 					return ID;
 				}
 {sid}			{
-					/* leading and trailing quotes are not passed to scanstr */
-					yytext[strlen(yytext) - 1] = '\0';
-					yylval.str = scanstr(yytext+1);
-					yytext[strlen(yytext)] = '"';	/* restore yytext */
+					/* strip quotes and escapes */
+					yylval.str = DeescapeQuotedString(yytext);
 					return ID;
 				}
 

src/backend/catalog/genbki.pl

@@ -845,17 +845,15 @@ sub print_bki_insert
 		# since that represents a NUL char in C code.
 		$bki_value = '' if $bki_value eq '\0';
 
-		# Handle single quotes by doubling them, and double quotes by
-		# converting them to octal escapes, because that's what the
+		# Handle single quotes by doubling them, because that's what the
 		# bootstrap scanner requires.  We do not process backslashes
 		# specially; this allows escape-string-style backslash escapes
 		# to be used in catalog data.
 		$bki_value =~ s/'/''/g;
-		$bki_value =~ s/"/\\042/g;
 
 		# Quote value if needed.  We need not quote values that satisfy
 		# the "id" pattern in bootscanner.l, currently "[-A-Za-z0-9_]+".
-		$bki_value = sprintf(qq'"%s"', $bki_value)
+		$bki_value = sprintf("'%s'", $bki_value)
 		  if length($bki_value) == 0
 		  or $bki_value =~ /[^-A-Za-z0-9_]/;
 

src/backend/parser/scansup.c

@@ -1,8 +1,7 @@
 /*-------------------------------------------------------------------------
  *
  * scansup.c
- *	  support routines for the lex/flex scanner, used by both the normal
- * backend as well as the bootstrap backend
+ *	  scanner support routines used by the core lexer
  *
  * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
@@ -20,98 +19,6 @@
 #include "mb/pg_wchar.h"
 #include "parser/scansup.h"
 
-/* ----------------
- *		scanstr
- *
- * if the string passed in has escaped codes, map the escape codes to actual
- * chars
- *
- * the string returned is palloc'd and should eventually be pfree'd by the
- * caller!
- * ----------------
- */
-
-char *
-scanstr(const char *s)
-{
-	char	   *newStr;
-	int			len,
-				i,
-				j;
-
-	if (s == NULL || s[0] == '\0')
-		return pstrdup("");
-
-	len = strlen(s);
-
-	newStr = palloc(len + 1);	/* string cannot get longer */
-
-	for (i = 0, j = 0; i < len; i++)
-	{
-		if (s[i] == '\'')
-		{
-			/*
-			 * Note: if scanner is working right, unescaped quotes can only
-			 * appear in pairs, so there should be another character.
-			 */
-			i++;
-			/* The bootstrap parser is not as smart, so check here. */
-			Assert(s[i] == '\'');
-			newStr[j] = s[i];
-		}
-		else if (s[i] == '\\')
-		{
-			i++;
-			switch (s[i])
-			{
-				case 'b':
-					newStr[j] = '\b';
-					break;
-				case 'f':
-					newStr[j] = '\f';
-					break;
-				case 'n':
-					newStr[j] = '\n';
-					break;
-				case 'r':
-					newStr[j] = '\r';
-					break;
-				case 't':
-					newStr[j] = '\t';
-					break;
-				case '0':
-				case '1':
-				case '2':
-				case '3':
-				case '4':
-				case '5':
-				case '6':
-				case '7':
-					{
-						int			k;
-						long		octVal = 0;
-
-						for (k = 0;
-							 s[i + k] >= '0' && s[i + k] <= '7' && k < 3;
-							 k++)
-							octVal = (octVal << 3) + (s[i + k] - '0');
-						i += k - 1;
-						newStr[j] = ((char) octVal);
-					}
-					break;
-				default:
-					newStr[j] = s[i];
-					break;
-			}					/* switch */
-		}						/* s[i] == '\\' */
-		else
-			newStr[j] = s[i];
-		j++;
-	}
-	newStr[j] = '\0';
-	return newStr;
-}
-
 
 /*
  * downcase_truncate_identifier() --- do appropriate downcasing and

src/backend/utils/misc/guc-file.l

@@ -55,7 +55,6 @@ static void record_config_file_error(const char *errmsg,
 						 ConfigVariable **tail_p);
 
 static int	GUC_flex_fatal(const char *msg);
-static char *GUC_scanstr(const char *s);
 
 /* LCOV_EXCL_START */
 
@@ -797,7 +796,7 @@ ParseConfigFp(FILE *fp, const char *config_file, int depth, int elevel,
 			token != GUC_UNQUOTED_STRING)
 			goto parse_error;
 		if (token == GUC_STRING)	/* strip quotes and escapes */
-			opt_value = GUC_scanstr(yytext);
+			opt_value = DeescapeQuotedString(yytext);
 		else
 			opt_value = pstrdup(yytext);
 
@@ -1132,22 +1131,25 @@ FreeConfigVariable(ConfigVariable *item)
 
 
 /*
- *		scanstr
+ *		DeescapeQuotedString
  *
  * Strip the quotes surrounding the given string, and collapse any embedded
  * '' sequences and backslash escapes.
  *
- * the string returned is palloc'd and should eventually be pfree'd by the
+ * The string returned is palloc'd and should eventually be pfree'd by the
  * caller.
+ *
+ * This is exported because it is also used by the bootstrap scanner.
  */
-static char *
-GUC_scanstr(const char *s)
+char *
+DeescapeQuotedString(const char *s)
 {
 	char	   *newStr;
 	int			len,
 				i,
 				j;
 
+	/* We just Assert that there are leading and trailing quotes */
 	Assert(s != NULL && s[0] == '\'');
 	len = strlen(s);
 	Assert(len >= 2);

src/bin/initdb/initdb.c

@@ -331,12 +331,9 @@ escape_quotes(const char *src)
 
 /*
  * Escape a field value to be inserted into the BKI data.
- * Here, we first run the value through escape_quotes (which
- * will be inverted by the backend's scanstr() function) and
- * then overlay special processing of double quotes, which
- * bootscanner.l will only accept as data if converted to octal
- * representation ("\042").  We always wrap the value in double
- * quotes, even if that isn't strictly necessary.
+ * Run the value through escape_quotes (which will be inverted
+ * by the backend's DeescapeQuotedString() function), then wrap
+ * the value in single quotes, even if that isn't strictly necessary.
  */
 static char *
 escape_quotes_bki(const char *src)
@@ -345,30 +342,13 @@ escape_quotes_bki(const char *src)
 	char	   *data = escape_quotes(src);
 	char	   *resultp;
 	char	   *datap;
-	int			nquotes = 0;
 
-	/* count double quotes in data */
-	datap = data;
-	while ((datap = strchr(datap, '"')) != NULL)
-	{
-		nquotes++;
-		datap++;
-	}
-
-	result = (char *) pg_malloc(strlen(data) + 3 + nquotes * 3);
+	result = (char *) pg_malloc(strlen(data) + 3);
 	resultp = result;
-	*resultp++ = '"';
+	*resultp++ = '\'';
 	for (datap = data; *datap; datap++)
-	{
-		if (*datap == '"')
-		{
-			strcpy(resultp, "\\042");
-			resultp += 4;
-		}
-		else
-			*resultp++ = *datap;
-	}
-	*resultp++ = '"';
+		*resultp++ = *datap;
+	*resultp++ = '\'';
 	*resultp = '\0';
 
 	free(data);

src/include/parser/scansup.h

@@ -1,8 +1,7 @@
 /*-------------------------------------------------------------------------
  *
  * scansup.h
- *	  scanner support routines.  used by both the bootstrap lexer
- * as well as the normal lexer
+ *	  scanner support routines used by the core lexer
  *
  * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
@@ -15,8 +14,6 @@
 #ifndef SCANSUP_H
 #define SCANSUP_H
 
-extern char *scanstr(const char *s);
-
 extern char *downcase_truncate_identifier(const char *ident, int len,
 										  bool warn);
 

src/include/utils/guc.h

@@ -155,6 +155,7 @@ extern bool ParseConfigDirectory(const char *includedir,
 								 ConfigVariable **head_p,
 								 ConfigVariable **tail_p);
 extern void FreeConfigVariables(ConfigVariable *list);
+extern char *DeescapeQuotedString(const char *s);
 
 /*
  * The possible values of an enum variable are specified by an array of