plpython: Restore alternative output for plpython_error test.

In db23464715f I removed the alternative output for plpython_error. Wrongly
so, because the output changed in Python 3.5, not Python 3.

src/pl/plpython/expected/plpython_error.out

@@ -243,7 +243,7 @@ $$
 plpy.nonexistent
 $$ LANGUAGE plpython3u;
 SELECT toplevel_attribute_error();
-ERROR:  AttributeError: module 'plpy' has no attribute 'nonexistent'
+ERROR:  AttributeError: 'module' object has no attribute 'nonexistent'
 CONTEXT:  Traceback (most recent call last):
   PL/Python function "toplevel_attribute_error", line 2, in <module>
     plpy.nonexistent

src/pl/plpython/expected/plpython_error_5.out

@@ -0,0 +1,447 @@
+-- test error handling, i forgot to restore Warn_restart in
+-- the trigger handler once. the errors and subsequent core dump were
+-- interesting.
+/* Flat out Python syntax error
+ */
+CREATE FUNCTION python_syntax_error() RETURNS text
+        AS
+'.syntaxerror'
+        LANGUAGE plpython3u;
+ERROR:  could not compile PL/Python function "python_syntax_error"
+DETAIL:  SyntaxError: invalid syntax (<string>, line 2)
+/* With check_function_bodies = false the function should get defined
+ * and the error reported when called
+ */
+SET check_function_bodies = false;
+CREATE FUNCTION python_syntax_error() RETURNS text
+        AS
+'.syntaxerror'
+        LANGUAGE plpython3u;
+SELECT python_syntax_error();
+ERROR:  could not compile PL/Python function "python_syntax_error"
+DETAIL:  SyntaxError: invalid syntax (<string>, line 2)
+/* Run the function twice to check if the hashtable entry gets cleaned up */
+SELECT python_syntax_error();
+ERROR:  could not compile PL/Python function "python_syntax_error"
+DETAIL:  SyntaxError: invalid syntax (<string>, line 2)
+RESET check_function_bodies;
+/* Flat out syntax error
+ */
+CREATE FUNCTION sql_syntax_error() RETURNS text
+        AS
+'plpy.execute("syntax error")'
+        LANGUAGE plpython3u;
+SELECT sql_syntax_error();
+ERROR:  spiexceptions.SyntaxError: syntax error at or near "syntax"
+LINE 1: syntax error
+        ^
+QUERY:  syntax error
+CONTEXT:  Traceback (most recent call last):
+  PL/Python function "sql_syntax_error", line 1, in <module>
+    plpy.execute("syntax error")
+PL/Python function "sql_syntax_error"
+/* check the handling of uncaught python exceptions
+ */
+CREATE FUNCTION exception_index_invalid(text) RETURNS text
+	AS
+'return args[1]'
+	LANGUAGE plpython3u;
+SELECT exception_index_invalid('test');
+ERROR:  IndexError: list index out of range
+CONTEXT:  Traceback (most recent call last):
+  PL/Python function "exception_index_invalid", line 1, in <module>
+    return args[1]
+PL/Python function "exception_index_invalid"
+/* check handling of nested exceptions
+ */
+CREATE FUNCTION exception_index_invalid_nested() RETURNS text
+	AS
+'rv = plpy.execute("SELECT test5(''foo'')")
+return rv[0]'
+	LANGUAGE plpython3u;
+SELECT exception_index_invalid_nested();
+ERROR:  spiexceptions.UndefinedFunction: function test5(unknown) does not exist
+LINE 1: SELECT test5('foo')
+               ^
+HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
+QUERY:  SELECT test5('foo')
+CONTEXT:  Traceback (most recent call last):
+  PL/Python function "exception_index_invalid_nested", line 1, in <module>
+    rv = plpy.execute("SELECT test5('foo')")
+PL/Python function "exception_index_invalid_nested"
+/* a typo
+ */
+CREATE FUNCTION invalid_type_uncaught(a text) RETURNS text
+	AS
+'if "plan" not in SD:
+	q = "SELECT fname FROM users WHERE lname = $1"
+	SD["plan"] = plpy.prepare(q, [ "test" ])
+rv = plpy.execute(SD["plan"], [ a ])
+if len(rv):
+	return rv[0]["fname"]
+return None
+'
+	LANGUAGE plpython3u;
+SELECT invalid_type_uncaught('rick');
+ERROR:  spiexceptions.UndefinedObject: type "test" does not exist
+CONTEXT:  Traceback (most recent call last):
+  PL/Python function "invalid_type_uncaught", line 3, in <module>
+    SD["plan"] = plpy.prepare(q, [ "test" ])
+PL/Python function "invalid_type_uncaught"
+/* for what it's worth catch the exception generated by
+ * the typo, and return None
+ */
+CREATE FUNCTION invalid_type_caught(a text) RETURNS text
+	AS
+'if "plan" not in SD:
+	q = "SELECT fname FROM users WHERE lname = $1"
+	try:
+		SD["plan"] = plpy.prepare(q, [ "test" ])
+	except plpy.SPIError as ex:
+		plpy.notice(str(ex))
+		return None
+rv = plpy.execute(SD["plan"], [ a ])
+if len(rv):
+	return rv[0]["fname"]
+return None
+'
+	LANGUAGE plpython3u;
+SELECT invalid_type_caught('rick');
+NOTICE:  type "test" does not exist
+ invalid_type_caught 
+---------------------
+ 
+(1 row)
+
+/* for what it's worth catch the exception generated by
+ * the typo, and reraise it as a plain error
+ */
+CREATE FUNCTION invalid_type_reraised(a text) RETURNS text
+	AS
+'if "plan" not in SD:
+	q = "SELECT fname FROM users WHERE lname = $1"
+	try:
+		SD["plan"] = plpy.prepare(q, [ "test" ])
+	except plpy.SPIError as ex:
+		plpy.error(str(ex))
+rv = plpy.execute(SD["plan"], [ a ])
+if len(rv):
+	return rv[0]["fname"]
+return None
+'
+	LANGUAGE plpython3u;
+SELECT invalid_type_reraised('rick');
+ERROR:  plpy.Error: type "test" does not exist
+CONTEXT:  Traceback (most recent call last):
+  PL/Python function "invalid_type_reraised", line 6, in <module>
+    plpy.error(str(ex))
+PL/Python function "invalid_type_reraised"
+/* no typo no messing about
+ */
+CREATE FUNCTION valid_type(a text) RETURNS text
+	AS
+'if "plan" not in SD:
+	SD["plan"] = plpy.prepare("SELECT fname FROM users WHERE lname = $1", [ "text" ])
+rv = plpy.execute(SD["plan"], [ a ])
+if len(rv):
+	return rv[0]["fname"]
+return None
+'
+	LANGUAGE plpython3u;
+SELECT valid_type('rick');
+ valid_type 
+------------
+ 
+(1 row)
+
+/* error in nested functions to get a traceback
+*/
+CREATE FUNCTION nested_error() RETURNS text
+	AS
+'def fun1():
+	plpy.error("boom")
+
+def fun2():
+	fun1()
+
+def fun3():
+	fun2()
+
+fun3()
+return "not reached"
+'
+	LANGUAGE plpython3u;
+SELECT nested_error();
+ERROR:  plpy.Error: boom
+CONTEXT:  Traceback (most recent call last):
+  PL/Python function "nested_error", line 10, in <module>
+    fun3()
+  PL/Python function "nested_error", line 8, in fun3
+    fun2()
+  PL/Python function "nested_error", line 5, in fun2
+    fun1()
+  PL/Python function "nested_error", line 2, in fun1
+    plpy.error("boom")
+PL/Python function "nested_error"
+/* raising plpy.Error is just like calling plpy.error
+*/
+CREATE FUNCTION nested_error_raise() RETURNS text
+	AS
+'def fun1():
+	raise plpy.Error("boom")
+
+def fun2():
+	fun1()
+
+def fun3():
+	fun2()
+
+fun3()
+return "not reached"
+'
+	LANGUAGE plpython3u;
+SELECT nested_error_raise();
+ERROR:  plpy.Error: boom
+CONTEXT:  Traceback (most recent call last):
+  PL/Python function "nested_error_raise", line 10, in <module>
+    fun3()
+  PL/Python function "nested_error_raise", line 8, in fun3
+    fun2()
+  PL/Python function "nested_error_raise", line 5, in fun2
+    fun1()
+  PL/Python function "nested_error_raise", line 2, in fun1
+    raise plpy.Error("boom")
+PL/Python function "nested_error_raise"
+/* using plpy.warning should not produce a traceback
+*/
+CREATE FUNCTION nested_warning() RETURNS text
+	AS
+'def fun1():
+	plpy.warning("boom")
+
+def fun2():
+	fun1()
+
+def fun3():
+	fun2()
+
+fun3()
+return "you''ve been warned"
+'
+	LANGUAGE plpython3u;
+SELECT nested_warning();
+WARNING:  boom
+   nested_warning   
+--------------------
+ you've been warned
+(1 row)
+
+/* AttributeError at toplevel used to give segfaults with the traceback
+*/
+CREATE FUNCTION toplevel_attribute_error() RETURNS void AS
+$$
+plpy.nonexistent
+$$ LANGUAGE plpython3u;
+SELECT toplevel_attribute_error();
+ERROR:  AttributeError: module 'plpy' has no attribute 'nonexistent'
+CONTEXT:  Traceback (most recent call last):
+  PL/Python function "toplevel_attribute_error", line 2, in <module>
+    plpy.nonexistent
+PL/Python function "toplevel_attribute_error"
+/* Calling PL/Python functions from SQL and vice versa should not lose context.
+ */
+CREATE OR REPLACE FUNCTION python_traceback() RETURNS void AS $$
+def first():
+  second()
+
+def second():
+  third()
+
+def third():
+  plpy.execute("select sql_error()")
+
+first()
+$$ LANGUAGE plpython3u;
+CREATE OR REPLACE FUNCTION sql_error() RETURNS void AS $$
+begin
+  select 1/0;
+end
+$$ LANGUAGE plpgsql;
+CREATE OR REPLACE FUNCTION python_from_sql_error() RETURNS void AS $$
+begin
+  select python_traceback();
+end
+$$ LANGUAGE plpgsql;
+CREATE OR REPLACE FUNCTION sql_from_python_error() RETURNS void AS $$
+plpy.execute("select sql_error()")
+$$ LANGUAGE plpython3u;
+SELECT python_traceback();
+ERROR:  spiexceptions.DivisionByZero: division by zero
+CONTEXT:  Traceback (most recent call last):
+  PL/Python function "python_traceback", line 11, in <module>
+    first()
+  PL/Python function "python_traceback", line 3, in first
+    second()
+  PL/Python function "python_traceback", line 6, in second
+    third()
+  PL/Python function "python_traceback", line 9, in third
+    plpy.execute("select sql_error()")
+PL/Python function "python_traceback"
+SELECT sql_error();
+ERROR:  division by zero
+CONTEXT:  SQL statement "select 1/0"
+PL/pgSQL function sql_error() line 3 at SQL statement
+SELECT python_from_sql_error();
+ERROR:  spiexceptions.DivisionByZero: division by zero
+CONTEXT:  Traceback (most recent call last):
+  PL/Python function "python_traceback", line 11, in <module>
+    first()
+  PL/Python function "python_traceback", line 3, in first
+    second()
+  PL/Python function "python_traceback", line 6, in second
+    third()
+  PL/Python function "python_traceback", line 9, in third
+    plpy.execute("select sql_error()")
+PL/Python function "python_traceback"
+SQL statement "select python_traceback()"
+PL/pgSQL function python_from_sql_error() line 3 at SQL statement
+SELECT sql_from_python_error();
+ERROR:  spiexceptions.DivisionByZero: division by zero
+CONTEXT:  Traceback (most recent call last):
+  PL/Python function "sql_from_python_error", line 2, in <module>
+    plpy.execute("select sql_error()")
+PL/Python function "sql_from_python_error"
+/* check catching specific types of exceptions
+ */
+CREATE TABLE specific (
+    i integer PRIMARY KEY
+);
+CREATE FUNCTION specific_exception(i integer) RETURNS void AS
+$$
+from plpy import spiexceptions
+try:
+    plpy.execute("insert into specific values (%s)" % (i or "NULL"));
+except spiexceptions.NotNullViolation as e:
+    plpy.notice("Violated the NOT NULL constraint, sqlstate %s" % e.sqlstate)
+except spiexceptions.UniqueViolation as e:
+    plpy.notice("Violated the UNIQUE constraint, sqlstate %s" % e.sqlstate)
+$$ LANGUAGE plpython3u;
+SELECT specific_exception(2);
+ specific_exception 
+--------------------
+ 
+(1 row)
+
+SELECT specific_exception(NULL);
+NOTICE:  Violated the NOT NULL constraint, sqlstate 23502
+ specific_exception 
+--------------------
+ 
+(1 row)
+
+SELECT specific_exception(2);
+NOTICE:  Violated the UNIQUE constraint, sqlstate 23505
+ specific_exception 
+--------------------
+ 
+(1 row)
+
+/* SPI errors in PL/Python functions should preserve the SQLSTATE value
+ */
+CREATE FUNCTION python_unique_violation() RETURNS void AS $$
+plpy.execute("insert into specific values (1)")
+plpy.execute("insert into specific values (1)")
+$$ LANGUAGE plpython3u;
+CREATE FUNCTION catch_python_unique_violation() RETURNS text AS $$
+begin
+    begin
+        perform python_unique_violation();
+    exception when unique_violation then
+        return 'ok';
+    end;
+    return 'not reached';
+end;
+$$ language plpgsql;
+SELECT catch_python_unique_violation();
+ catch_python_unique_violation 
+-------------------------------
+ ok
+(1 row)
+
+/* manually starting subtransactions - a bad idea
+ */
+CREATE FUNCTION manual_subxact() RETURNS void AS $$
+plpy.execute("savepoint save")
+plpy.execute("create table foo(x integer)")
+plpy.execute("rollback to save")
+$$ LANGUAGE plpython3u;
+SELECT manual_subxact();
+ERROR:  plpy.SPIError: SPI_execute failed: SPI_ERROR_TRANSACTION
+CONTEXT:  Traceback (most recent call last):
+  PL/Python function "manual_subxact", line 2, in <module>
+    plpy.execute("savepoint save")
+PL/Python function "manual_subxact"
+/* same for prepared plans
+ */
+CREATE FUNCTION manual_subxact_prepared() RETURNS void AS $$
+save = plpy.prepare("savepoint save")
+rollback = plpy.prepare("rollback to save")
+plpy.execute(save)
+plpy.execute("create table foo(x integer)")
+plpy.execute(rollback)
+$$ LANGUAGE plpython3u;
+SELECT manual_subxact_prepared();
+ERROR:  plpy.SPIError: SPI_execute_plan failed: SPI_ERROR_TRANSACTION
+CONTEXT:  Traceback (most recent call last):
+  PL/Python function "manual_subxact_prepared", line 4, in <module>
+    plpy.execute(save)
+PL/Python function "manual_subxact_prepared"
+/* raising plpy.spiexception.* from python code should preserve sqlstate
+ */
+CREATE FUNCTION plpy_raise_spiexception() RETURNS void AS $$
+raise plpy.spiexceptions.DivisionByZero()
+$$ LANGUAGE plpython3u;
+DO $$
+BEGIN
+	SELECT plpy_raise_spiexception();
+EXCEPTION WHEN division_by_zero THEN
+	-- NOOP
+END
+$$ LANGUAGE plpgsql;
+/* setting a custom sqlstate should be handled
+ */
+CREATE FUNCTION plpy_raise_spiexception_override() RETURNS void AS $$
+exc = plpy.spiexceptions.DivisionByZero()
+exc.sqlstate = 'SILLY'
+raise exc
+$$ LANGUAGE plpython3u;
+DO $$
+BEGIN
+	SELECT plpy_raise_spiexception_override();
+EXCEPTION WHEN SQLSTATE 'SILLY' THEN
+	-- NOOP
+END
+$$ LANGUAGE plpgsql;
+/* test the context stack trace for nested execution levels
+ */
+CREATE FUNCTION notice_innerfunc() RETURNS int AS $$
+plpy.execute("DO LANGUAGE plpython3u $x$ plpy.notice('inside DO') $x$")
+return 1
+$$ LANGUAGE plpython3u;
+CREATE FUNCTION notice_outerfunc() RETURNS int AS $$
+plpy.execute("SELECT notice_innerfunc()")
+return 1
+$$ LANGUAGE plpython3u;
+\set SHOW_CONTEXT always
+SELECT notice_outerfunc();
+NOTICE:  inside DO
+CONTEXT:  PL/Python anonymous code block
+SQL statement "DO LANGUAGE plpython3u $x$ plpy.notice('inside DO') $x$"
+PL/Python function "notice_innerfunc"
+SQL statement "SELECT notice_innerfunc()"
+PL/Python function "notice_outerfunc"
+ notice_outerfunc 
+------------------
+                1
+(1 row)
+