changes in function-like macros

[andreasstieger]

Considering the following change of an API. We have a function-like macro where a trailing semicolon was removed:

http://svn.apache.org/viewvc/serf/trunk/serf_bucket_types.h?r1=1719435&r2=1719434&pathrev=1719435&view=patch

--- serf/trunk/serf_bucket_types.h  2015/12/11 14:41:41 1719434
+++ serf/trunk/serf_bucket_types.h  2015/12/11 14:44:59 1719435
@@ -392,10 +392,10 @@
     serf_bucket_alloc_t *allocator);

 #define SERF_BUCKET_SIMPLE_STRING(s,a) \
-    serf_bucket_simple_create(s, strlen(s), NULL, NULL, a);
+    serf_bucket_simple_create(s, strlen(s), NULL, NULL, a)

 #define SERF_BUCKET_SIMPLE_STRING_LEN(s,l,a) \
-    serf_bucket_simple_create(s, l, NULL, NULL, a);
+    serf_bucket_simple_create(s, l, NULL, NULL, a)

 /* ==================================================================== */

The old version could be used as a "function call" without semicolon, with semicolon (in which case it would expand to a double semicolon), but not as a function argument.

The new version can be used as a function argument, but must also carry a semicolon when called like a function as a single statement. The dev team has noted that this change is not 100% backwards compatible. In fact some calling code itself needed to change: http://svn.apache.org/viewvc?view=revision&revision=1719435 http://svn.apache.org/viewvc/serf/trunk/test/test_buckets.c?r1=1719435&r2=1719434&pathrev=1719435

A check could be added for all function-like macros as to whether there is a change w.r.t. using them as a function macro, or requiring a trailing semicolon when calling the macro. This could be addressed by trial compilation.

[aponomarenko]

Hello,

Thank you for reporting issues.

Such changes in function-like macro are filtered out from the "Binary compatibility" tab of the report by the constantFilter() subroutine.

Is this change listed in the "Source compatibility" tab of the report?

[andreasstieger]

This is a minor source compatibility issue, but it is not show in the source incompatibility tab.

#!/bin/sh
svn co -r1719435 https://svn.apache.org/repos/asf/serf/trunk serf-r1719435
svn co -r1719434 https://svn.apache.org/repos/asf/serf/trunk serf-r1719434
pushd serf-r1719435
scons
popd
pushd serf-r1719434
scons
popd
abi-compliance-checker -o serf-r1719434 -v1 r1719434 -n serf-r1719435 -v2 r1719435 -l libserf

The report returns 100% source compatibility, and I made sure the header containing this change was picked up.

Using GCC 4.8 (x86_64-suse-linux, target: x86_64) WARNING: Not working properly with GCC 4.8. Please update or downgrade GCC or use a local installation by --gcc-path=PATH option. checking header(s) r1719434 ... Using C++ compatibility mode checking header(s) r1719435 ... Using C++ compatibility mode comparing ABIs ... comparing APIs ... creating compatibility report ... result: COMPATIBLE total "Binary" compatibility problems: 0, warnings: 0 total "Source" compatibility problems: 0, warnings: 0 see detailed report: compat_reports/libserf/r1719434_to_r1719435/compat_report.html