VLC @3.0.7.1_4: error: multiple methods named 'value' found with mismatched result, parameter type or attributes

[ccottap (Carlos Cotta)]

I'm trying to install VLC +quartz-x11+svg and get a build error. The problem seems to be in the following section:

:info:build libtool: compile:  /usr/bin/clang -DHAVE_CONFIG_H -I. -I.. -DMODULE_STRING=\"macosx\" -D__PLUGIN__ -I./access -I./codec -I../include -I../include -I/opt/local/include -D__unix__=1 -Wno-unknown-pragmas -I/opt/local/lib/live/liveMedia/
include -isysroot/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.15.sdk -I/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_multimedia_VLC/VLC/work/vlc-3.0.7.1/contrib/include -fobjc-exceptions -fobjc-arc -pipe -Os -isysroot/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.15.sdk -arch x86_64 -D_INTL_REDIRECT_MACROS -std=gnu11 -Werror=partial-availability -I/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_multimedia_VLC/VLC/work/vlc-3.0.7.1/contrib/include -F/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_multimedia_VLC/VLC/work/vlc-3.0.7.1/contrib -F/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_multimedia_VLC/VLC/work/vlc-3.0.7.1/contrib/Frameworks -fvisibility=hidden -O3 -funroll-loops -fomit-frame-pointer -MT gui/macosx/libmacosx_plugin_la-VLCPlaylistInfo.lo -MD -MP -MF gui/macosx/.deps/libmacosx_plugin_la-VLCPlaylistInfo.Tpo -c gui/macosx/VLCPlaylistInfo.m  -fno-common -DPIC -o gui/macosx/.libs/libmacosx_plugin_la-VLCPlaylistInfo.o
:info:build gui/macosx/VLCPlaylistInfo.m:402:16: error: multiple methods named 'value' found with mismatched result, parameter type or attributes
:info:build         return [item value];
:info:build                ^~~~~~~~~~~~
:info:build /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.15.sdk/System/Library/Frameworks/Foundation.framework/Headers/NSMetadata.h:137:43: note: one possibility
:info:build @property (nullable, readonly, retain) id value;
:info:build                                           ^~~~~
:info:build /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.15.sdk/System/Library/Frameworks/Foundation.framework/Headers/NSURL.h:472:42: note: also found
:info:build @property (nullable, readonly) NSString *value;
:info:build                                          ^~~~~
:info:build /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.15.sdk/System/Library/Frameworks/Foundation.framework/Headers/NSHTTPCookie.h:327:38: note: also found
:info:build @property (readonly, copy) NSString *value;
:info:build                                      ^~~~~
:info:build /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.15.sdk/System/Library/Frameworks/Foundation.framework/Headers/NSMetadata.h:151:33: note: also found
:info:build @property (readonly, retain) id value;
:info:build                                 ^~~~~
:info:build /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.15.sdk/System/Library/Frameworks/AppKit.framework/Headers/NSDictionaryController.h:25:33: note: also found
:info:build @property (nullable, strong) id value;
:info:build                                 ^~~~~
:info:build /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.15.sdk/System/Library/Frameworks/AppKit.framework/Headers/NSStepperTouchBarItem.h:35:18: note: also found
:info:build @property double value;
:info:build                  ^~~~~
:info:build gui/macosx/VLCPlaylistInfo.h:110:33: note: also found
:info:build @property (readwrite) NSString *value;
:info:build                                 ^~~~~
:info:build 1 error generated.
:info:build make[4]: *** [gui/macosx/libmacosx_plugin_la-VLCPlaylistInfo.lo] Error 1
:info:build make[4]: Target `all-am' not remade because of errors.
:info:build make[4]: Leaving directory `/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_multimedia_VLC/VLC/work/vlc-3.0.7.1/modules'
:info:build make[3]: *** [all-recursive] Error 1
:info:build make[3]: Leaving directory `/opt/local/var/macports/build/_opt_local_var_macports_sources_rsyn
c.macports.org_macports_release_tarballs_ports_multimedia_VLC/VLC/work/vlc-3.0.7.1/modules'
:info:build make[2]: *** [all] Error 2
:info:build make[2]: Leaving directory `/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_multimedia_VLC/VLC/work/vlc-3.0.7.1/modules'

OSX version: 10.15 (19A602) Xcode version: 11.0 (11A420a)

[RJVB (René Bertin)]

OK, this goes beyond my ObjC knowledge.

item here (VLCPlaylistInfo.m:402 is an id, which to me is the base class for anything in ObjC. All the alternative classes in the error message return either a NSString* value or an id value; NSString* should cast to id transparently *AFAIK*.

@ccottap: Are you capable of tinkering a bit with casting the return value ((id)[item value]), or does anyone else reading this have a clue. If not I'll have to see if upstream has a fix (or wait for one).

[ccottap (Carlos Cotta)]

I have just tried casting the return value to id but it keeps giving the same error:

:info:build gui/macosx/VLCPlaylistInfo.m:402:20: error: multiple methods named 'value' found with mismatched result, parameter type or attributes
:info:build         return (id)[item value];
:info:build                    ^~~~~~~~~~~~

[RJVB (René Bertin)]

Thanks.

I had to dig rather deep in the VLC git repo (the Mac sources were reorganised thoroughly), but found

commit 3d3cdb244e8902ac676a3da4bda51b976c16c140
Author: Felix Paul Kühne <fkuehne@videolan.org>
Date:   Tue Sep 17 21:20:26 2019 +0200

    macosx: future compilation fix
    
    In the future, the use of a 'value' property on custom classes will lead to conflicts with the SDK.

I'll swallow my opinion on what I already feared, I'll try to backport that change and post a patch here.

[RJVB (René Bertin)]

tentative patch for 10.15

[ccottap (Carlos Cotta)]

The patch works fine for me. The compilation is now completed without error. Thanks!

[stilwellweather]

Just upgraded to macOS 10.15 (19A603) with Xcode 11.1 (11A1027) and MacPorts 2.6.2

VLC failed to build for me, even with the above patch.

Log file after cleaning attached

[RJVB (René Bertin)]

@stilwellweather: how did you apply the patch? Because the error in your logfile is the same as the one in the OP.

Either way, my fix got applied, so please try again after doing a selfupdate, and report back.

[ryandesign (Ryan Carsten Schmidt)]

The fix was committed as part of [d16d4f80882fa56c5b97f704cbdd3645d168d1a4/macports-ports].