Fix GCOV not working for PHP-7.4 and master branches

[gerardroche]

Code coverage reports (make lcov), since commit eef8522 (7.4 branch),
generates incorrect coverage and emits warnings. Simplifying
the Makefile.gcov file has the side-effect of resolving the issue.

Processing sapi/cli/php_http_parser.gcda
php-src/lcov_data/sapi/cli/php_http_parser.gcda:stamp mismatch with notes file
geninfo: WARNING: gcov did not create any files for php-src/lcov_data/sapi/cli/php_http_parser.gcda!
...
Processing ext/mbstring/mb_gpc.gcda
php-src/lcov_data/ext/mbstring/mb_gpc.gcda:stamp mismatch with notes file
geninfo: WARNING: gcov did not create any files for php-src/lcov_data/ext/mbstring/mb_gpc.gcda!

Closes: https://bugs.php.net/bug.php?id=52718.
See also: https://bugs.php.net/bug.php?id=78288.

[carusogabriel]

Please see https://externals.io/message/107113.

[gerardroche]

So it looks there are two issues: generating coverage locally (this PR should fix that) and publishing the coverage which looks complicated and as yet undecided.

[carusogabriel]

So it looks there are two issues: generating coverage locally (this PR should fix that) and publishing the coverage which looks complicated and as yet undecided.

Indeed. Thanks for change the PR message.

[nikic]

I applied this patch and used

sudo apt install lcov
./configure --enable-debug --enable-lcov CCACHE_DISABLE=1
make lcov-html TESTS="-j6"

Which gives me a lot of warnings:

Processing main/SAPI.gcda
geninfo: WARNING: /home/nikic/php-7.4-gcov/main/SAPI.gcno: Overlong record at end of file!
/home/nikic/php-7.4-gcov/main/SAPI.gcno:version 'A83*', prefer 'A74*'
/home/nikic/php-7.4-gcov/main/SAPI.gcno:no functions found
geninfo: WARNING: gcov did not create any files for /home/nikic/php-7.4-gcov/main/SAPI.gcda!

[nikic]

Okay, looks like this is gcov vs gcc version mismatch on my side. After running

sudo update-alternatives --install /usr/bin/gcov gcov /usr/bin/gcov-8 90

the version warning goes away, but instead I get:

Processing main/SAPI.gcda
geninfo: WARNING: /home/nikic/php-7.4-gcov/main/SAPI.gcno: Overlong record at end of file!
geninfo: WARNING: cannot find an entry for #home#nikic#php-7.4-gcov#Zend#zend_hash.h.gcov in .gcno file, skipping file!
geninfo: WARNING: cannot find an entry for #home#nikic#php-7.4-gcov#Zend#zend_string.h.gcov in .gcno file, skipping file!
geninfo: WARNING: cannot find an entry for #home#nikic#php-7.4-gcov#Zend#zend_types.h.gcov in .gcno file, skipping file!
geninfo: WARNING: cannot find an entry for #home#nikic#php-7.4-gcov#main#SAPI.c.gcov in .gcno file, skipping file!

[nikic]

Based on linux-test-project/lcov#38 it looks like my lcov version is not compatible with GCC 8. After reconfiguring with

./config.nice CC=gcc-7 LTP="lcov --gcov-tool gcov-7"

it works.

As to the patch itself, I guess the disadvantage of this change is that now the ignored files will still be processed and only discarded afterwards. But that doesn't seem like much of a problem nowadays.

[nikic]

Merged as 9cc1bf5 into 7.4. While at it, I've also added the --no-external flag to exclude system headers.

Would you be interested in also looking into the Azure Pipelines integration, as mentioned in https://externals.io/message/107113?

[gerardroche]

Sometimes warnings can be caused by missing libraries which need to added to the exclusion list. The version of gcov I've been testing against is:

gcov (Ubuntu 7.4.0-1ubuntu1~18.04.1) 7.4.0
lcov: LCOV version 1.13
genhtml: LCOV version 1.13
gcovr 3.4

gcov.php,net is using LCOV 1.10.

As to the patch itself, I guess the disadvantage of this change is that now the ignored files will still be processed and only discarded afterwards. But that doesn't seem like much of a problem nowadays.

I couldn't find a way around that. It's probably still faster than the alternatives.

I've also added the --no-external flag to exclude system headers.

Nice. The coverage report is starting to look a lot less cluttered.

Would you be interested in also looking into the Azure Pipelines integration, as mentioned in https://externals.io/message/107113?

I'm looking into it. I'll follow up on the mailing list.