compiler warning read_objtype_from_string()

Peter Eisentraut wrote:

I'm getting the following compiler warning (using nondefault
optimization options):

objectaddress.c: In function 'read_objtype_from_string':
objectaddress.c:2309:9: error: 'type' may be used uninitialized in this
function [-Werror=maybe-uninitialized]
return type;

Umm. I think it can only be uninitialized if we fall out of the end of
the array, in which case we're supposed to throw the ERROR and never
return. Is that not working?

The comment for the function says

* Return ObjectType for the given object type as given by
* getObjectTypeDescription; if no valid ObjectType code exists, but it's a
* possible output type from getObjectTypeDescription, return -1.

But the claim that it can return -1 does not seem supported by the code.

Actually, it is -- but the -1 value comes from the ObjectType array.
Perhaps the comment should state that explicitely.

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�lvaro Herrera https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

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Alvaro Herrera <alvherre@2ndquadrant.com> writes:

Peter Eisentraut wrote:

I'm getting the following compiler warning (using nondefault
optimization options):
objectaddress.c: In function 'read_objtype_from_string':
objectaddress.c:2309:9: error: 'type' may be used uninitialized in this
function [-Werror=maybe-uninitialized]
return type;

Umm. I think it can only be uninitialized if we fall out of the end of
the array, in which case we're supposed to throw the ERROR and never
return. Is that not working?

I do not think you should assume that the compiler is smart enough to
deduce that, nor that all compilers even know ereport(ERROR) doesn't
return. Personally I don't see the point of the "type" variable at
all, anyway. I would have written this as

int i;

for (i = 0; i < lengthof(ObjectTypeMap); i++)
{
if (strcmp(ObjectTypeMap[i].tm_name, objtype) == 0)
return ObjectTypeMap[i].tm_type;
}
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("unrecognized object type \"%s\"", objtype)));
return -1; /* keep compiler quiet */

regards, tom lane

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Tom Lane wrote:

I do not think you should assume that the compiler is smart enough to
deduce that, nor that all compilers even know ereport(ERROR) doesn't
return. Personally I don't see the point of the "type" variable at
all, anyway. I would have written this as

[code]

Makes sense. I will patch it that way.

--
�lvaro Herrera https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

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