postgres.git / summary / log / commit / refs
commit d64fad6669926c95f1a2e49ebec58ed4412be1a0
Author: Andrew Gierth <rhodiumtoad@postgresql.org>
Date: Thu Aug 23 17:29:18 2018 +0000
Fix lexing of standard multi-character operators in edge cases.
Commits c6b3c939b (which fixed the precedence of >=, <=, <> operators)
and 865f14a2d (which added support for the standard => notation for
named arguments) created a class of lexer tokens which look like
multi-character operators but which have their own token IDs distinct
from Op. However, longest-match rules meant that following any of
these tokens with another operator character, as in (1<>-1), would
cause them to be incorrectly returned as Op.
The error here isn't immediately obvious, because the parser would
usually still find the correct operator via the Op token, but there
were more subtle problems:
1. If immediately followed by a comment or +-, >= <= <> would be given
the old precedence of Op rather than the correct new precedence;
2. If followed by a comment, != would be returned as Op rather than as
NOT_EQUAL, causing it not to be found at all;
3. If followed by a comment or +-, the => token for named arguments
would be lexed as Op, causing the argument to be mis-parsed as a
simple expression, usually causing an error.
Fix by explicitly checking for the operators in the {operator} code
block in addition to all the existing special cases there.
Backpatch to 9.5 where the problem was introduced.
Analysis and patch by me; review by Tom Lane.
Discussion: https://postgr.es/m/87va851ppl.fsf@news-spur.riddles.org.uk
src/backend/parser/scan.l | 28 ++++++++++
src/fe_utils/psqlscan.l | 9 ++++
src/interfaces/ecpg/preproc/pgc.l | 28 ++++++++++
src/test/regress/expected/create_operator.out | 74 +++++++++++++++++++++++++++
src/test/regress/expected/polymorphism.out | 36 +++++++++++++
src/test/regress/sql/create_operator.sql | 31 +++++++++++
src/test/regress/sql/polymorphism.sql | 15 ++++++
7 files changed, 221 insertions(+)
diff --git a/src/backend/parser/scan.l b/src/backend/parser/scan.l
index c1767efabb6..c95607da854 100644
--- a/src/backend/parser/scan.l
+++ b/src/backend/parser/scan.l
@@ -335,6 +335,15 @@ identifier {ident_start}{ident_cont}*
typecast "::"
dot_dot \.\.
colon_equals ":="
+
+/*
+ * These operator-like tokens (unlike the above ones) also match the {operator}
+ * rule, which means that they might be overridden by a longer match if they
+ * are followed by a comment start or a + or - character. Accordingly, if you
+ * add to this list, you must also add corresponding code to the {operator}
+ * block to return the correct token in such cases. (This is not needed in
+ * psqlscan.l since the token value is ignored there.)
+ */
equals_greater "=>"
less_equals "<="
greater_equals ">="
@@ -925,6 +934,25 @@ other .
if (nchars == 1 &&
strchr(",()[].;:+-*/%^<>=", yytext[0]))
return yytext[0];
+ /*
+ * Likewise, if what we have left is two chars, and
+ * those match the tokens ">=", "<=", "=>", "<>" or
+ * "!=", then we must return the appropriate token
+ * rather than the generic Op.
+ */
+ if (nchars == 2)
+ {
+ if (yytext[0] == '=' && yytext[1] == '>')
+ return EQUALS_GREATER;
+ if (yytext[0] == '>' && yytext[1] == '=')
+ return GREATER_EQUALS;
+ if (yytext[0] == '<' && yytext[1] == '=')
+ return LESS_EQUALS;
+ if (yytext[0] == '<' && yytext[1] == '>')
+ return NOT_EQUALS;
+ if (yytext[0] == '!' && yytext[1] == '=')
+ return NOT_EQUALS;
+ }
}
/*
diff --git a/src/fe_utils/psqlscan.l b/src/fe_utils/psqlscan.l
index e6c7938f752..3f9a7b42b41 100644
--- a/src/fe_utils/psqlscan.l
+++ b/src/fe_utils/psqlscan.l
@@ -296,6 +296,15 @@ identifier {ident_start}{ident_cont}*
typecast "::"
dot_dot \.\.
colon_equals ":="
+
+/*
+ * These operator-like tokens (unlike the above ones) also match the {operator}
+ * rule, which means that they might be overridden by a longer match if they
+ * are followed by a comment start or a + or - character. Accordingly, if you
+ * add to this list, you must also add corresponding code to the {operator}
+ * block to return the correct token in such cases. (This is not needed in
+ * psqlscan.l since the token value is ignored there.)
+ */
equals_greater "=>"
less_equals "<="
greater_equals ">="
diff --git a/src/interfaces/ecpg/preproc/pgc.l b/src/interfaces/ecpg/preproc/pgc.l
index 0a90bead921..5ed185a20b6 100644
--- a/src/interfaces/ecpg/preproc/pgc.l
+++ b/src/interfaces/ecpg/preproc/pgc.l
@@ -241,6 +241,15 @@ array ({ident_cont}|{whitespace}|[\[\]\+\-\*\%\/\(\)\>\.])*
typecast "::"
dot_dot \.\.
colon_equals ":="
+
+/*
+ * These operator-like tokens (unlike the above ones) also match the {operator}
+ * rule, which means that they might be overridden by a longer match if they
+ * are followed by a comment start or a + or - character. Accordingly, if you
+ * add to this list, you must also add corresponding code to the {operator}
+ * block to return the correct token in such cases. (This is not needed in
+ * psqlscan.l since the token value is ignored there.)
+ */
equals_greater "=>"
less_equals "<="
greater_equals ">="
@@ -728,6 +737,25 @@ cppline {space}*#([^i][A-Za-z]*|{if}|{ifdef}|{ifndef}|{import})((\/\*[^*/]*\*+
if (nchars == 1 &&
strchr(",()[].;:+-*/%^<>=", yytext[0]))
return yytext[0];
+ /*
+ * Likewise, if what we have left is two chars, and
+ * those match the tokens ">=", "<=", "=>", "<>" or
+ * "!=", then we must return the appropriate token
+ * rather than the generic Op.
+ */
+ if (nchars == 2)
+ {
+ if (yytext[0] == '=' && yytext[1] == '>')
+ return EQUALS_GREATER;
+ if (yytext[0] == '>' && yytext[1] == '=')
+ return GREATER_EQUALS;
+ if (yytext[0] == '<' && yytext[1] == '=')
+ return LESS_EQUALS;
+ if (yytext[0] == '<' && yytext[1] == '>')
+ return NOT_EQUALS;
+ if (yytext[0] == '!' && yytext[1] == '=')
+ return NOT_EQUALS;
+ }
}
base_yylval.str = mm_strdup(yytext);
diff --git a/src/test/regress/expected/create_operator.out b/src/test/regress/expected/create_operator.out
index 3a216c2ca8f..f3e41777318 100644
--- a/src/test/regress/expected/create_operator.out
+++ b/src/test/regress/expected/create_operator.out
@@ -37,6 +37,80 @@ CREATE OPERATOR => (
ERROR: syntax error at or near "=>"
LINE 1: CREATE OPERATOR => (
^
+-- lexing of <=, >=, <>, != has a number of edge cases
+-- (=> is tested elsewhere)
+-- this is legal because ! is not allowed in sql ops
+CREATE OPERATOR !=- (
+ leftarg = int8, -- right unary
+ procedure = numeric_fac
+);
+SELECT 2 !=-;
+ ?column?
+----------
+ 2
+(1 row)
+
+-- make sure lexer returns != as <> even in edge cases
+SELECT 2 !=/**/ 1, 2 !=/**/ 2;
+ ?column? | ?column?
+----------+----------
+ t | f
+(1 row)
+
+SELECT 2 !=-- comment to be removed by psql
+ 1;
+ ?column?
+----------
+ t
+(1 row)
+
+DO $$ -- use DO to protect -- from psql
+ declare r boolean;
+ begin
+ execute $e$ select 2 !=-- comment
+ 1 $e$ into r;
+ raise info 'r = %', r;
+ end;
+$$;
+INFO: r = t
+-- check that <= etc. followed by more operator characters are returned
+-- as the correct token with correct precedence
+SELECT true<>-1 BETWEEN 1 AND 1; -- BETWEEN has prec. above <> but below Op
+ ?column?
+----------
+ t
+(1 row)
+
+SELECT false<>/**/1 BETWEEN 1 AND 1;
+ ?column?
+----------
+ t
+(1 row)
+
+SELECT false<=-1 BETWEEN 1 AND 1;
+ ?column?
+----------
+ t
+(1 row)
+
+SELECT false>=-1 BETWEEN 1 AND 1;
+ ?column?
+----------
+ t
+(1 row)
+
+SELECT 2<=/**/3, 3>=/**/2, 2<>/**/3;
+ ?column? | ?column? | ?column?
+----------+----------+----------
+ t | t | t
+(1 row)
+
+SELECT 3<=/**/2, 2>=/**/3, 2<>/**/2;
+ ?column? | ?column? | ?column?
+----------+----------+----------
+ f | f | f
+(1 row)
+
-- Should fail. CREATE OPERATOR requires USAGE on SCHEMA
BEGIN TRANSACTION;
CREATE ROLE regress_rol_op1;
diff --git a/src/test/regress/expected/polymorphism.out b/src/test/regress/expected/polymorphism.out
index 91cfb743b63..42253be2ee9 100644
--- a/src/test/regress/expected/polymorphism.out
+++ b/src/test/regress/expected/polymorphism.out
@@ -1478,6 +1478,42 @@ select dfunc('a'::text, 'b', flag => true); -- mixed notation
a
(1 row)
+-- this tests lexer edge cases around =>
+select dfunc(a =>-1);
+ dfunc
+-------
+ -1
+(1 row)
+
+select dfunc(a =>+1);
+ dfunc
+-------
+ 1
+(1 row)
+
+select dfunc(a =>/**/1);
+ dfunc
+-------
+ 1
+(1 row)
+
+select dfunc(a =>--comment to be removed by psql
+ 1);
+ dfunc
+-------
+ 1
+(1 row)
+
+-- need DO to protect the -- from psql
+do $$
+ declare r integer;
+ begin
+ select dfunc(a=>-- comment
+ 1) into r;
+ raise info 'r = %', r;
+ end;
+$$;
+INFO: r = 1
-- check reverse-listing of named-arg calls
CREATE VIEW dfview AS
SELECT q1, q2,
diff --git a/src/test/regress/sql/create_operator.sql b/src/test/regress/sql/create_operator.sql
index 0e5d6356bc3..0579cb95e1d 100644
--- a/src/test/regress/sql/create_operator.sql
+++ b/src/test/regress/sql/create_operator.sql
@@ -41,6 +41,37 @@ CREATE OPERATOR => (
procedure = numeric_fac
);
+-- lexing of <=, >=, <>, != has a number of edge cases
+-- (=> is tested elsewhere)
+
+-- this is legal because ! is not allowed in sql ops
+CREATE OPERATOR !=- (
+ leftarg = int8, -- right unary
+ procedure = numeric_fac
+);
+SELECT 2 !=-;
+-- make sure lexer returns != as <> even in edge cases
+SELECT 2 !=/**/ 1, 2 !=/**/ 2;
+SELECT 2 !=-- comment to be removed by psql
+ 1;
+DO $$ -- use DO to protect -- from psql
+ declare r boolean;
+ begin
+ execute $e$ select 2 !=-- comment
+ 1 $e$ into r;
+ raise info 'r = %', r;
+ end;
+$$;
+
+-- check that <= etc. followed by more operator characters are returned
+-- as the correct token with correct precedence
+SELECT true<>-1 BETWEEN 1 AND 1; -- BETWEEN has prec. above <> but below Op
+SELECT false<>/**/1 BETWEEN 1 AND 1;
+SELECT false<=-1 BETWEEN 1 AND 1;
+SELECT false>=-1 BETWEEN 1 AND 1;
+SELECT 2<=/**/3, 3>=/**/2, 2<>/**/3;
+SELECT 3<=/**/2, 2>=/**/3, 2<>/**/2;
+
-- Should fail. CREATE OPERATOR requires USAGE on SCHEMA
BEGIN TRANSACTION;
CREATE ROLE regress_rol_op1;
diff --git a/src/test/regress/sql/polymorphism.sql b/src/test/regress/sql/polymorphism.sql
index 45ae7a23aa7..5cdfcd2e69c 100644
--- a/src/test/regress/sql/polymorphism.sql
+++ b/src/test/regress/sql/polymorphism.sql
@@ -785,6 +785,21 @@ select dfunc('a'::text, 'b', flag => false); -- mixed notation
select dfunc('a'::text, 'b', true); -- full positional notation
select dfunc('a'::text, 'b', flag => true); -- mixed notation
+-- this tests lexer edge cases around =>
+select dfunc(a =>-1);
+select dfunc(a =>+1);
+select dfunc(a =>/**/1);
+select dfunc(a =>--comment to be removed by psql
+ 1);
+-- need DO to protect the -- from psql
+do $$
+ declare r integer;
+ begin
+ select dfunc(a=>-- comment
+ 1) into r;
+ raise info 'r = %', r;
+ end;
+$$;
-- check reverse-listing of named-arg calls
CREATE VIEW dfview AS
[parent: 2dbfbd630bc9]