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Avoid premature de-doubling of quote marks in ECPG strings.
If you write the literal 'abc''def' in an EXEC SQL command, that will come out the other end as 'abc'def', triggering a syntax error in the backend. Likewise, "abc""def" is reduced to "abc"def" which is wrong syntax for a quoted identifier. The cause is that the lexer thinks it should emit just one quote mark, whereas what it really should do is keep the string as-is. Add some docs and test cases, too. Although this seems clearly a bug, I fear users wouldn't appreciate changing it in minor releases. Some may well be working around it by applying an extra doubling of affected quotes, as for example sql/dyntest.pgc has been doing. Per investigation of a report from 1250kv, although this isn't exactly what he/she was on about. Discussion: https://postgr.es/m/673825.1603223178@sss.pgh.pa.us
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-20
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7 files changed

+28
-20
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‎doc/src/sgml/ecpg.sgml‎

Lines changed: 14 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -31,7 +31,7 @@
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specially marked sections. To build the program, the source code (<filename>*.pgc</filename>)
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is first passed through the embedded SQL preprocessor, which converts it
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to an ordinary C program (<filename>*.c</filename>), and afterwards it can be processed by a C
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compiler. (For details about the compiling and linking see <xref linkend="ecpg-process"/>).
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compiler. (For details about the compiling and linking see <xref linkend="ecpg-process"/>.)
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Converted ECPG applications call functions in the libpq library
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through the embedded SQL library (ecpglib), and communicate with
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the PostgreSQL server using the normal frontend-backend protocol.
@@ -63,11 +63,22 @@ EXEC SQL ...;
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</programlisting>
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These statements syntactically take the place of a C statement.
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Depending on the particular statement, they can appear at the
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global level or within a function. Embedded
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global level or within a function.
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</para>
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<para>
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Embedded
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<acronym>SQL</acronym> statements follow the case-sensitivity rules of
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normal <acronym>SQL</acronym> code, and not those of C. Also they allow nested
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C-style comments that are part of the SQL standard. The C part of the
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C-style comments as per the SQL standard. The C part of the
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program, however, follows the C standard of not accepting nested comments.
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Embedded <acronym>SQL</acronym> statements likewise use SQL rules, not
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C rules, for parsing quoted strings and identifiers.
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(See <xref linkend="sql-syntax-strings"/> and
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<xref linkend="sql-syntax-identifiers"/> respectively. Note that
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ECPG assumes that <varname>standard_conforming_strings</varname>
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is <literal>on</literal>.)
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Of course, the C part of the program follows C quoting rules.
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</para>
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<para>

‎src/interfaces/ecpg/preproc/pgc.l‎

Lines changed: 3 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -623,11 +623,8 @@ cppline {space}*#([^i][A-Za-z]*|{if}|{ifdef}|{ifndef}|{import})((\/\*[^*/]*\*+
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}
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}
625625

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<xq,xe,xn,xus>{xqdouble} { addlitchar('\''); }
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<xqc>{xqcquote} {
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addlitchar('\\');
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addlitchar('\'');
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}
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<xq,xe,xn,xus>{xqdouble} { addlit(yytext, yyleng); }
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<xqc>{xqcquote} { addlit(yytext, yyleng); }
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<xq,xqc,xn,xus>{xqinside} { addlit(yytext, yyleng); }
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<xe>{xeinside} {
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addlit(yytext, yyleng);
@@ -736,7 +733,7 @@ cppline {space}*#([^i][A-Za-z]*|{if}|{ifdef}|{ifndef}|{import})((\/\*[^*/]*\*+
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return UIDENT;
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}
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<xd,xui>{xddouble} {
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addlitchar('"');
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addlit(yytext, yyleng);
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}
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<xd,xui>{xdinside} {
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addlit(yytext, yyleng);

‎src/interfaces/ecpg/test/expected/preproc-strings.c‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -45,7 +45,7 @@ int main(void)
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#line 13 "strings.pgc"
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{ ECPGdo(__LINE__, 0, 1, NULL, 0, ECPGst_normal, "select 'abcdef' , N'abcdef' as foo , E'abc\\bdef' as \"foo\" , U&'d\\0061t\\0061' as U&\"foo\" , U&'d!+000061t!+000061' UESCAPE '!' , $foo$abc$def$foo$", ECPGt_EOIT,
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{ ECPGdo(__LINE__, 0, 1, NULL, 0, ECPGst_normal, "select 'abc''d\\ef' , N'abc''d\\ef' as foo , E'abc''d\\\\ef' as \"foo\"\"bar\" , U&'d\\0061t\\0061' as U&\"foo\"\"bar\" , U&'d!+000061t!+000061' UESCAPE '!' , $foo$abc$def$foo$", ECPGt_EOIT,
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ECPGt_char,&(s1),(long)0,(long)1,(1)*sizeof(char),
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ECPGt_NO_INDICATOR, NULL , 0L, 0L, 0L,
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ECPGt_char,&(s2),(long)0,(long)1,(1)*sizeof(char),

‎src/interfaces/ecpg/test/expected/preproc-strings.stderr‎

Lines changed: 4 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -8,23 +8,23 @@
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[NO_PID]: sqlca: code: 0, state: 00000
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[NO_PID]: ecpg_process_output on line 13: OK: SET
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[NO_PID]: sqlca: code: 0, state: 00000
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[NO_PID]: ecpg_execute on line 15: query: select 'abcdef' , N'abcdef' as foo , E'abc\bdef' as "foo" , U&'d\0061t\0061' as U&"foo" , U&'d!+000061t!+000061' UESCAPE '!' , $foo$abc$def$foo$; with 0 parameter(s) on connection ecpg1_regression
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[NO_PID]: ecpg_execute on line 15: query: select 'abc''d\ef' , N'abc''d\ef' as foo , E'abc''d\\ef' as "foo""bar" , U&'d\0061t\0061' as U&"foo""bar" , U&'d!+000061t!+000061' UESCAPE '!' , $foo$abc$def$foo$; with 0 parameter(s) on connection ecpg1_regression
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[NO_PID]: sqlca: code: 0, state: 00000
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[NO_PID]: ecpg_execute on line 15: using PQexec
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[NO_PID]: sqlca: code: 0, state: 00000
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[NO_PID]: ecpg_process_output on line 15: correctly got 1 tuples with 6 fields
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[NO_PID]: sqlca: code: 0, state: 00000
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[NO_PID]: ecpg_store_result on line 15: allocating memory for 1 tuples
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[NO_PID]: sqlca: code: 0, state: 00000
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[NO_PID]: ecpg_get_data on line 15: RESULT: abcdef offset: -1; array: no
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[NO_PID]: ecpg_get_data on line 15: RESULT: abc'd\ef offset: -1; array: no
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[NO_PID]: sqlca: code: 0, state: 00000
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[NO_PID]: ecpg_store_result on line 15: allocating memory for 1 tuples
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[NO_PID]: sqlca: code: 0, state: 00000
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[NO_PID]: ecpg_get_data on line 15: RESULT: abcdef offset: -1; array: no
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[NO_PID]: ecpg_get_data on line 15: RESULT: abc'd\ef offset: -1; array: no
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[NO_PID]: sqlca: code: 0, state: 00000
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[NO_PID]: ecpg_store_result on line 15: allocating memory for 1 tuples
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[NO_PID]: sqlca: code: 0, state: 00000
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[NO_PID]: ecpg_get_data on line 15: RESULT: abcdef offset: -1; array: no
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[NO_PID]: ecpg_get_data on line 15: RESULT: abc'd\ef offset: -1; array: no
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[NO_PID]: sqlca: code: 0, state: 00000
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[NO_PID]: ecpg_store_result on line 15: allocating memory for 1 tuples
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[NO_PID]: sqlca: code: 0, state: 00000

‎src/interfaces/ecpg/test/expected/preproc-strings.stdout‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1 +1 @@
1-
abcdef abcdef abcdef data data abc$def
1+
abc'd\ef abc'd\ef abc'd\ef data data abc$def

‎src/interfaces/ecpg/test/preproc/strings.pgc‎

Lines changed: 4 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -12,10 +12,10 @@ int main(void)
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1313
exec sql set standard_conforming_strings to on;
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15-
exec sql select 'abcdef',
16-
N'abcdef' AS foo,
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E'abc\bdef' AS "foo",
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U&'d\0061t\0061' AS U&"foo",
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exec sql select 'abc''d\ef',
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N'abc''d\ef' AS foo,
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E'abc''d\\ef' AS "foo""bar",
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U&'d\0061t\0061' AS U&"foo""bar",
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U&'d!+000061t!+000061' uescape '!',
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$foo$abc$def$foo$
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into :s1, :s2, :s3, :s4, :s5, :s6;

‎src/interfaces/ecpg/test/sql/dyntest.pgc‎

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Original file line numberDiff line numberDiff line change
@@ -51,7 +51,7 @@ main ()
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exec sql create table dyntest (name char (14), d float8, i int,
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bignumber int8, b boolean, comment text,
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day date);
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exec sql insert into dyntest values ('first entry', 14.7, 14, 123045607890, true, 'The world''''s most advanced open source database.', '1987-07-14');
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exec sql insert into dyntest values ('first entry', 14.7, 14, 123045607890, true, 'The world''s most advanced open source database.', '1987-07-14');
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exec sql insert into dyntest values ('second entry', 1407.87, 1407, 987065403210, false, 'The elephant never forgets.', '1999-11-5');
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exec sql prepare MYQUERY from :QUERY;

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