Build Setting Policy

BuildSettingPolicy.py

#!/usr/bin/python

# Hard-code the build settings that we feel strongly should 
# only be defined in a centralized location (.xcconfig files).
# These can also serve then to (at some point) confirm that the 
# values are indeed being defined by the .xcconfig files
def forbiddenBuildSettingKeys():
    return ["CLANG_CXX_LANGUAGE_STANDARD",
            "CLANG_CXX_LIBRARY",
            "CLANG_ENABLE_MODULES",
            "CLANG_MODULES_AUTOLINK",
            "CLANG_WARN_BOOL_CONVERSION",
            "CLANG_WARN_CONSTANT_CONVERSION",
            "CLANG_WARN_DIRECT_OBJC_ISA_USAGE",
            "CLANG_WARN_EMPTY_BODY",
            "CLANG_WARN_ENUM_CONVERSION",
            "CLANG_WARN_INT_CONVERSION",
            "CLANG_WARN_OBJC_ROOT_CLASS",
            "CLANG_WARN_UNREACHABLE_CODE",
            "CLANG_WARN__DUPLICATE_METHOD_MATCH",
            "COMBINE_HIDPI_IMAGES",
            "COPY_PHASE_STRIP",
            "COPY_PHASE_STRIP",
            "GCC_VERSION",
            "GCC_C_LANGUAGE_STANDARD",
            "GCC_DYNAMIC_NO_PIC",
            "GCC_ENABLE_OBJC_EXCEPTIONS",
            "GCC_GENERATE_DEBUGGING_SYMBOLS",
            "GCC_GENERATE_DEBUGGING_SYMBOLS",
            "GCC_MODEL_TUNING",
            "GCC_OPTIMIZATION_LEVEL",
            "GCC_PRECOMPILE_PREFIX_HEADER",
            "GCC_WARN_64_TO_32_BIT_CONVERSION",
            "GCC_WARN_ABOUT_RETURN_TYPE",
            "GCC_WARN_UNINITIALIZED_AUTOS",
            "GCC_WARN_TYPECHECK_CALLS_TO_PRINTF",
            "GCC_WARN_UNKNOWN_PRAGMAS",
            "GCC_WARN_UNUSED_LABEL",
            "GCC_WARN_CHECK_SWITCH_STATEMENTS",
            "GCC_WARN_UNUSED_PARAMETER",
            "GCC_WARN_SIGN_COMPARE",
            "GCC_WARN_UNUSED_VALUE",
            "GCC_TREAT_IMPLICIT_FUNCTION_DECLARATIONS_AS_ERRORS",
            "GCC_WARN_UNDECLARED_SELECTOR",
            "GCC_WARN_EFFECTIVE_CPLUSPLUS_VIOLATIONS", # not sure this is even used any more by clang
            "GCC_WARN_ABOUT_GLOBAL_CONSTRUCTORS", # same
            "GCC_USE_GCC3_PFE_SUPPORT", # same
            "GCC_TREAT_WARNINGS_AS_ERRORS",
            "GCC_WARN_MISSING_PARENTHESES",
            "GCC_WARN_SHADOW",
            "GCC_WARN_SIGN_COMPARE"
            "GCC_WARN_UNUSED_PARAMETER",
            "GCC_WARN_ABOUT_MISSING_NEWLINE",
            "MACOSX_DEPLOYMENT_TARGET",
            "ENABLE_STRICT_OBJC_MSGSEND",
            "GCC_WARN_UNUSED_VARIABLE",
            "ZERO_LINK",
            "CODE_SIGN_IDENTITY",
            "CODE_SIGN_IDENTITY[sdk=iphoneos*]",
            "CODE_SIGN_IDENTITY[sdk=macosx*]",
            "MTL_ENABLE_DEBUG_INFO", # Should be enabled only if we ever have Metal-specific targets
            "SDKROOT",
            "SKIP_INSTALL",
            "ARCHS",
            "CLANG_ENABLE_OBJC_ARC",
            "ALWAYS_SEARCH_USER_PATHS",
            "DEFINES_MODULE", # Should be imposed by the framework-flavored build config
            "GCC_WARN_UNUSED_FUNCTION",
            "GCC_INCREASE_PRECOMPILED_HEADER_SHARING",
            "GCC_ALTIVEC_EXTENSIONS", # No longer pertinent to i386/x86_64
            "DEBUG_INFORMATION_FORMAT",
            "GCC_WARN_ABOUT_MISSING_PROTOTYPES",
            "GCC_FAST_OBJC_DISPATCH", # Only pertinent to PPC builds
            "ENABLE_NS_ASSERTIONS",
            "SUPPORTED_PLATFORMS", # Should impose this through xcconfig as/if needed
            "IPHONEOS_DEPLOYMENT_TARGET",
            "VERSIONING_SYSTEM", # We don't use apple-generic, so zap targets that specify it 
            "VERSION_INFO_PREFIX",
            "VALIDATE_PRODUCT",
            "GCC_SYMBOLS_PRIVATE_EXTERN", # Should be managed at xcconfig level unless we get on a kick of ratcheting down exported symbols
            "KEEP_PRIVATE_EXTERNS",
            "DYLIB_INSTALL_NAME_BASE", # Our only uses of this were redundant with INSTALL_PATH default
            "ONLY_ACTIVE_ARCH",
            "DEPLOYMENT_POSTPROCESSING",
            "IBC_ERRORS",
            "WARNING_CFLAGS",
            "OTHER_REZFLAGS",
            "OTHER_LDFLAGS[arch=ppc]", # We shouldn't any longer have ppc-specific settings
            "GCC_WARN_ABOUT_DEPRECATED_FUNCTIONS",
            "PREBINDING",
            "PRINCIPAL_CLASS",
            "GCC_ENABLE_FIX_AND_CONTINUE",
            "STRIP_STYLE", # Seems irrelevant when using separate symbols file 
            "PRECOMPS_INCLUDE_HEADERS_FROM_BUILT_PRODUCTS_DIR",
            "GCC_THUMB_SUPPORT",
            "USER_HEADER_SEARCH_PATHS", # Don't think we have legitimate reasons for this style of import (plain quotes style for foreign, non-library style headers)      
            "INFOPLIST_EXPAND_BUILD_SETTINGS", # On by default anyway
            "GCC_WARN_FOUR_CHARACTER_CONSTANTS",
            "GCC_ENABLE_TRIGRAPHS",
            "LIBRARY_STYLE", # Think this is ignored in favor of MACH_O_TYPE
            "DEBUGGING_SYMBOLS", # Also obsolete
            "RS_TARGET_OTHER_CFLAGS", # SHOULD ONLY BE DEFINED IN xcconfig!
            ]

# Whitelisted build settings make eminent sense at the project or target level. However,
# we should review this from time to time and/or consider changing our approach such that 
# even app-specific settings are all specified in .xcconfig files that in turn import 
# from the standard ones
def whitelistedBuildSettingKeys():
    return ["APPLICATION_VERSION",
            "FRAMEWORK_SEARCH_PATHS",
            "GCC_PREFIX_HEADER",
            "INFOPLIST_FILE",
            "PRODUCT_NAME",
            "WRAPPER_EXTENSION",    # Until and unless we decide common bundles deserve own xcconfig
            "CODE_SIGN_ENTITLEMENTS",
            "PROVISIONING_PROFILE",
            "PROVISIONING_PROFILE[sdk=iphoneos*]",
            "DYLIB_COMPATIBILITY_VERSION",
            "DYLIB_CURRENT_VERSION",
            "TARGETED_DEVICE_FAMILY",
            "CURRENT_PROJECT_VERSION", # We don't actively use these version values but they are indeed target-specific and could be adopted at some point
            "FRAMEWORK_VERSION",   
            "GCC_PFE_FILE_C_DIALECTS", # Allowed, though ideally should be removed if it defines our default from .xcconfig, which is just objective-c
            "GCC_PREPROCESSOR_DEFINITIONS", # Currently mostly used to -DDEBUG=1 ... should .xcconfig all that
            "ASSETCATALOG_COMPILER_APPICON_NAME",
            "TEST_HOST", # legitimate for injected test targets
            "BUNDLE_LOADER", # same
            ]
            
# Semantically different from whitelist because they are possibly worthy of review and 
# effort to eliminate, but shouldn't be nagged about or automatically removed.
# WOULD BE NICE to also support a mechanism for confirming that certain keys only have 
# values that meet certain criteria, are not redundant with default, etc.
#
# Recommended to stub this out when first examining a project for linting, to 
# evaluate afresh which of these are actually being used.
def greylistedBuildSettingKeys():
    return ["FRAMEWORK_SEARCH_PATHS_QUOTED_FOR_TARGET_1",
            "INSTALL_PATH", # Allowed for e.g. specific bundle types - move to xcconfig? Should generally be @rpath!
            "OTHER_LDFLAGS", # Often just specifies e.g. -framework Foundation -framework Cocoa, should ideally detect and delete bogus lines that are redundant with built-in framework linkage rules - ACTUALLY is this even still consulted by clang?
            "OTHER_CFLAGS", # Very questionable but not quite ready to wholesale zap it yet. Should at least zap cases where a target is redundantly specifying -DDEBUG when it would be inherited from debug xcconfig. But for example I think Mac App Store variants rely upon this to set -DRS_TARGET_MAC_APP_STORE=1 and sandboxed apps similarly. So some overriding, for now, is appropriate
            "LD_RUNPATH_SEARCH_PATHS", # There are only a few typical options here but e.g. RSScriptRunner uses a weird self-relative version currently ... look into whether this is bogus and can be replaced with @rpath standardized stuff
            "LIBRARY_SEARCH_PATHS", # Typically these shouldn't need to be expanded upon
            "APPLICATION_EXTENSION_API_ONLY", # Generally should be on by default but e.g. RSTestingKit needs to turn it off to link with XCTest without warning
            "HEADER_SEARCH_PATHS", # Used e.g. by RSWebClientCore to access libxml2 headers at build time
            "SECTORDER_FLAGS", # Don't think any of our targets have a good reason to use these
            "OTHER_LIBTOOL_FLAGS",
            "EXECUTABLE_EXTENSION", # Still used by some .o static library targets but why do we even still have those?
            "MACH_O_TYPE", # Also still declared on some static library targets
            "PUBLIC_HEADERS_FOLDER_PATH", # Shouldn't be used often, but e.g. the dependent CrashReporter framework underlying RSCrashReporter still does use it
            "OTHER_LDFLAGS[arch=i386]", # We shouldn't any longer have i386-specific settings, see if they are really necessary?           
            "OTHER_CODE_SIGN_FLAGS", # Used to e.g. add custom designated requirement text
            "SWIFT_INSTALL_OBJC_HEADER", # Swift build settings should be formalized as part of standard .xcconfig files but for now we are not really using swift except a tiny bit in Moto.app
            "SWIFT_OPTIMIZATION_LEVEL",
            "SWIFT_OBJC_BRIDGING_HEADER",
            ]