Merge branch 'warnings' into v2.15.x.

Clean up our handling of compiler warnings in a variety of ways,
and use #pragma rather than -Wno to only disable warnings where
necessary.

1 files changed, 19 insertions, 16 deletions

diff --git a/wscript b/wscript
index 72db83e2c..f874758dd 100644
--- a/wscript
+++ b/wscript
@@ -75,6 +75,7 @@ def options(opt):
     opt.add_option('--variant',           help='build variant (swaroop-studio, swaroop-theater)', choices=['swaroop-studio', 'swaroop-theater'])
     opt.add_option('--use-lld',           action='store_true', default=False, help='use lld linker')
     opt.add_option('--enable-disk',       action='store_true', default=False, help='build dcpomatic2_disk tool; requires Boost process, lwext4 and nanomsg libraries')
+    opt.add_option('--warnings-are-errors', action='store_true', default=False, help='build with -Werror')
 
 def configure(conf):
     conf.load('compiler_cxx')
@@ -106,22 +107,26 @@ def configure(conf):
                                        '-Wall',
                                        '-Wextra',
                                        '-Wwrite-strings',
-                                       '-Wsign-conversion',
-                                       # Remove auto_ptr warnings from libxml++-2.6
-                                       '-Wno-deprecated-declarations',
+                                       # I tried and failed to ignore these with _Pragma
                                        '-Wno-ignored-qualifiers',
-                                       '-Wno-parentheses',
                                        '-D_FILE_OFFSET_BITS=64'])
 
     if conf.options.force_cpp11:
         conf.env.append_value('CXXFLAGS', ['-std=c++11', '-DBOOST_NO_CXX11_SCOPED_ENUMS'])
 
+    if conf.options.warnings_are_errors:
+        conf.env.append_value('CXXFLAGS', '-Werror')
+
     if conf.env['CXX_NAME'] == 'gcc':
         gcc = conf.env['CC_VERSION']
-        if int(gcc[0]) >= 4 and int(gcc[1]) > 1:
-            conf.env.append_value('CXXFLAGS', ['-Wno-unused-result'])
-        if int(gcc[0]) >= 9:
-            conf.env.append_value('CXXFLAGS', ['-Wno-deprecated-copy'])
+        if int(gcc[0]) >= 8:
+            # I tried and failed to ignore these with _Pragma
+            conf.env.append_value('CXXFLAGS', ['-Wno-cast-function-type'])
+        elif int(gcc[0]) == 7:
+            # There appears to be a GCC bug which lingered from major versions 5--7 and which
+            # flags up these warnings all over the place in boost::optional.
+            # These seems to be the only practical way to hide it
+            conf.env.append_value('CXXFLAGS', ['-Wno-maybe-uninitialized'])
         have_c11 = int(gcc[0]) >= 4 and int(gcc[1]) >= 8 and int(gcc[2]) >= 1
     else:
         have_c11 = False
@@ -203,11 +208,8 @@ def configure(conf):
 
     # OSX
     if conf.env.TARGET_OSX:
-        conf.env.append_value('CXXFLAGS', ['-DDCPOMATIC_OSX', '-Wno-unused-function', '-Wno-unused-parameter', '-Wno-unused-local-typedef', '-Wno-potentially-evaluated-expression'])
+        conf.env.append_value('CXXFLAGS', ['-DDCPOMATIC_OSX'])
         conf.env.append_value('LINKFLAGS', '-headerpad_max_install_names')
-    else:
-        # Avoid the endless warnings about _t uninitialized in optional<>
-        conf.env.append_value('CXXFLAGS', '-Wno-maybe-uninitialized')
 
     #
     # Dependencies.
@@ -322,10 +324,10 @@ def configure(conf):
         if conf.options.workaround_gssapi:
             conf.env.LIB_SSH = ['gssapi_krb5']
     else:
-        conf.check_cc(fragment="""
+        conf.check_cxx(fragment="""
                                #include <libssh/libssh.h>\n
                                int main () {\n
-                               ssh_session s = ssh_new ();\n
+                               ssh_new ();\n
                                return 0;\n
                                }
                                """,
@@ -501,7 +503,7 @@ def configure(conf):
 
         conf.check_cxx(fragment="""
     			    #include <boost/thread.hpp>\n
-    			    int main() { boost::thread t (); }\n
+			    int main() { boost::thread t; }\n
 			    """,
                        msg='Checking for boost threading library',
                        libpath='/usr/local/lib',
@@ -550,8 +552,9 @@ def configure(conf):
                 deps.append('boost_filesystem%s' % boost_lib_suffix)
             conf.check_cxx(fragment="""
                                 #include <boost/process.hpp>\n
-                                int main() { boost::process::child* c = new boost::process::child("foo"); }\n
+                                int main() { new boost::process::child("foo"); }\n
                                 """,
+                           cxxflags='-Wno-unused-parameter',
                            msg='Checking for boost process library',
                            lib=deps,
                            uselib_store='BOOST_PROCESS')