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Allow IMPORT FOREIGN SCHEMA within pl/pgsql.

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Since IMPORT FOREIGN SCHEMA has an INTO clause, pl/pgsql needs to be
aware of that and avoid capturing the INTO as an INTO-variables clause.
This isn't hard, though it's annoying to have to make IMPORT a plpgsql
keyword just for this.  (Fortunately, we have the infrastructure now
to make it an unreserved keyword, so at least this shouldn't break any
existing pl/pgsql code.)

Per report from Merlin Moncure.  Back-patch to 9.5 where IMPORT FOREIGN
SCHEMA was introduced.

Report: <CAHyXU0wpHf2bbtKGL1gtUEFATCY86r=VKxfcACVcTMQ70mCyig@mail.gmail.com>
This commit is contained in:
Tom Lane 2016-07-12 18:06:50 -04:00
parent d3fbd5929c
commit baebab3ace
2 changed files with 39 additions and 9 deletions
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47
src/pl/plpgsql/src/pl_gram.y
View File

@ -287,6 +287,7 @@ static void check_raise_parameters(PLpgSQL_stmt_raise *stmt);
%token <keyword> K_GET
%token <keyword> K_HINT
%token <keyword> K_IF
%token <keyword> K_IMPORT
%token <keyword> K_IN
%token <keyword> K_INFO
%token <keyword> K_INSERT
@ -1929,7 +1930,11 @@ loop_body : proc_sect K_END K_LOOP opt_label ';'
* assignment. Give an appropriate complaint for that, instead of letting
* the core parser throw an unhelpful "syntax error".
*/
stmt_execsql : K_INSERT
stmt_execsql : K_IMPORT
{
$$ = make_execsql_stmt(K_IMPORT, @1);
}
| K_INSERT
{
$$ = make_execsql_stmt(K_INSERT, @1);
}
@ -2418,6 +2423,7 @@ unreserved_keyword :
| K_FORWARD
| K_GET
| K_HINT
| K_IMPORT
| K_INFO
| K_INSERT
| K_IS
@ -2843,12 +2849,32 @@ make_execsql_stmt(int firsttoken, int location)
plpgsql_IdentifierLookup = IDENTIFIER_LOOKUP_EXPR;
/*
* We have to special-case the sequence INSERT INTO, because we don't want
* that to be taken as an INTO-variables clause. Fortunately, this is the
* only valid use of INTO in a pl/pgsql SQL command, and INTO is already a
* fully reserved word in the main grammar. We have to treat it that way
* anywhere in the string, not only at the start; consider CREATE RULE
* containing an INSERT statement.
* Scan to the end of the SQL command. Identify any INTO-variables
* clause lurking within it, and parse that via read_into_target().
*
* Because INTO is sometimes used in the main SQL grammar, we have to be
* careful not to take any such usage of INTO as a pl/pgsql INTO clause.
* There are currently three such cases:
*
* 1. SELECT ... INTO. We don't care, we just override that with the
* pl/pgsql definition.
*
* 2. INSERT INTO. This is relatively easy to recognize since the words
* must appear adjacently; but we can't assume INSERT starts the command,
* because it can appear in CREATE RULE or WITH. Unfortunately, INSERT is
* *not* fully reserved, so that means there is a chance of a false match;
* but it's not very likely.
*
* 3. IMPORT FOREIGN SCHEMA ... INTO. This is not allowed in CREATE RULE
* or WITH, so we just check for IMPORT as the command's first token.
* (If IMPORT FOREIGN SCHEMA returned data someone might wish to capture
* with an INTO-variables clause, we'd have to work much harder here.)
*
* Fortunately, INTO is a fully reserved word in the main grammar, so
* at least we need not worry about it appearing as an identifier.
*
* Any future additional uses of INTO in the main grammar will doubtless
* break this logic again ... beware!
*/
tok = firsttoken;
for (;;)
@ -2861,9 +2887,12 @@ make_execsql_stmt(int firsttoken, int location)
break;
if (tok == 0)
yyerror("unexpected end of function definition");
if (tok == K_INTO && prev_tok != K_INSERT)
if (tok == K_INTO)
{
if (prev_tok == K_INSERT)
continue; /* INSERT INTO is not an INTO-target */
if (firsttoken == K_IMPORT)
continue; /* IMPORT ... INTO is not an INTO-target */
if (have_into)
yyerror("INTO specified more than once");
have_into = true;

1
src/pl/plpgsql/src/pl_scanner.c
View File

@ -127,6 +127,7 @@ static const ScanKeyword unreserved_keywords[] = {
PG_KEYWORD("forward", K_FORWARD, UNRESERVED_KEYWORD)
PG_KEYWORD("get", K_GET, UNRESERVED_KEYWORD)
PG_KEYWORD("hint", K_HINT, UNRESERVED_KEYWORD)
PG_KEYWORD("import", K_IMPORT, UNRESERVED_KEYWORD)
PG_KEYWORD("info", K_INFO, UNRESERVED_KEYWORD)
PG_KEYWORD("insert", K_INSERT, UNRESERVED_KEYWORD)
PG_KEYWORD("is", K_IS, UNRESERVED_KEYWORD)