CMakeFile produces VS2015 Projects with Link Errors

[randy-armstrong]

Ran cmake to create VS0125 projects with
-DHTTP_ONLY:BOOL=ON -DBUILD_CURL_EXE:BOOL=OFF
msbuild /p:Configuration=Debug CURL.sln

I expected it to work but a bunch of test programs failed with linker errors.

The cmake options don't make a difference.
Same problem with no options.

I reverted to 7_48_0 and everything was fine.

[bagder]

Can you please show us some of those errors too?

[randy-armstrong]

build\tests\unit\unit1603.vcxproj" (default target) (135) ->
  unit1603.obj : error LNK2019: unresolved external symbol _Curl_hash_init referenced in function _unit_setup [\src\curl\build\tests\unit\unit1603.vcxproj]
  unit1603.obj : error LNK2019: unresolved external symbol _Curl_hash_add referenced in function _test [src\curl\build\tests\unit\unit1603.vcxproj]
  unit1603.obj : error LNK2019: unresolved external symbol _Curl_hash_delete referenced in function _test [src\curl\build\tests\unit\unit1603.vcxproj]
  unit1603.obj : error LNK2019: unresolved external symbol _Curl_hash_pick referenced in function _test [src\curl\build\tests\unit\unit1603.vcxproj]
  unit1603.obj : error LNK2019: unresolved external symbol _Curl_hash_destroy referenced in function _unit_stop [src\curl\build\tests\unit\unit1603.vcxproj]
  unit1603.obj : error LNK2019: unresolved external symbol _Curl_hash_clean referenced in function _test [src\curl\build\tests\unit\unit1603.vcxproj]
  unit1603.obj : error LNK2019: unresolved external symbol _Curl_hash_str referenced in function _test [src\curl\build\tests\unit\unit1603.vcxproj]
  unit1603.obj : error LNK2019: unresolved external symbol _Curl_str_key_compare referenced in function _unit_setup [src\curl\build\tests\unit\unit1603.vcxproj]
  src\curl\build\tests\unit\Debug\unit1603.exe : fatal error LNK1120: 8 unresolved externals [src\curl\build\tests\unit\unit1603.vcxproj]

    1 Warning(s)
    38 Error(s)

[bagder]

Ok, yes the unit tests can only build with debug versions of libcurl since it requires that a bunch of otherwise hidden symbols are available - to get tested. As they're not part of the regular API, they're not reachable in a normal build.

I suppose the cmake build files need to skip building the unit tests unless that condition is met. That's what the autoconf based build does.

[bagder]

I should add that all the 16xx tests (that are in tests/unit) are such unit tests.

[randy-armstrong]

A cmake option to disable all tests would be nice,
When you use cmake to build for Visual Studio you end up with a single solution and you cannot pick and choose which projects build to without using the GUI (which is not good for automated builds).

[jay]

-DBUILD_TESTING=OFF

I tried building the tests just now, I also ran into problems.

[bagder]

Right, the cmake build should only try to build the unit tests when asked to build debug builds as otherwise it fails like this...

[snikulov]

@bagder @SparhawkSoftware @jay In fact Curl_hash_init symbols will be available if -DCURL_STATICLIB=ON because it's not exported as dllexport attribute.

@SparhawkSoftware So if you want to fix build use -DBUILD_TESTING=OFF or enable static linking with -DCURL_STATICLIB=ON (check appveyor configuration here https://ci.appveyor.com/project/curlorg/curl)

[bagder]

It is probably still a good idea to have the build script check if the unit tests can get built before doing that, to avoid this build error.

[snikulov]

@bagder Linux exports all symbols by default. So all Curl_hash is in libcurl.so library.
So here you should decide if same for Windows and Curl_hash... should use dllexport.

[bagder]

Aha! but that's a bug - it should hide symbols by default and what's what it does in the autoconf build! That's why the "regular" build can't be used for the unit test. Also, some unit tests use symbols that are otherwise marked static and I'm not sure they're always made available even if symbols aren't hidden.

[randy-armstrong]

Confirmed that -DBUILD_TESTING=OFF fixes my issue.

I should have noticed that flag in the CMAKE.

Adding this near the top would be nice:
option(BUILD_TESTING "This includes the unit tests. Only valid when building the static library" OFF)

[bagder]

The build should simply not build the unit tests if it can't link them...

[snikulov]

@SparhawkSoftware According to documentation this option already there and ON by default.

@bagder So what's the decision? Are Curl_hash_ functions optional? From which build option it depends?