[swift-dev] Categorization of warnings in Swift
Michael Ilseman
milseman at apple.com
Tue Jan 12 19:15:21 CST 2016
By keeping it in mind, do you mean to allow for more categories to be added in the future, or does this affect the fundamental design?
> On Jan 12, 2016, at 5:06 PM, Michael Gottesman <mgottesman at apple.com> wrote:
>
>
>> On Jan 12, 2016, at 9:44 AM, Michael Ilseman via swift-dev <swift-dev at swift.org <mailto:swift-dev at swift.org>> wrote:
>>
>> Hello, I'm interested in enabling finer-grained control over warning/error
>> reporting ala Clang. I've started to put in some infrastructure to
>> DiagnosticEngine, and now I'm at the point of determining categorization.
>>
>> I'd like some input (and maybe even some bikeshedding!) on the community's
>> thoughts and preferences here. Here's my take on the issue:
>>
>> When it comes to defining the categorization, I can see a few approaches:
>> Categorize based on broad language-feature/compiler-area. E.g. "Availability" or “CommandLineArguments”
>> Categorize based on the kind of warning. E.g. "Deprecated" or “Uninitialized"
>> Categorize based on severity or specificity of warnings. E.g. "Pedantic" or "UnusedValue" or "NullDereference"
>>
>> And, of course, I think that preference should be given to how people would
>> actively like to use the categories to control warnings. For example, there's
>> a handful of warnings that makes less sense in a REPL or rapid experimentation
>> environment, such as variable_never_mutated.
>>
>> Here's a straw-man proposal of some categorization. Of course, one developer's
>> annoying pedantic warning is another's life-saving code-smell detector. I am not
>> personally tied to these categorizations at all, I'm just interested in there
>> being something simple and basic. Below is a list of every warning in Swift with
>> an attempt to put it under a category.
>>
>>
>> Deprecated:
>> var_not_allowed_in_pattern
>> "Use of '%select{var|let}0' binding here is deprecated and will be "
>> "removed in a future version of Swift"
>> deprecated_c_style_for_stmt
>> "C-style for statement is deprecated and will be removed in a future "
>> "version of Swift"
>> deprecated_convention_attribute
>> "'@%0' attribute is deprecated; '@convention(%1)' should be used "
>> "instead"
>> availability_deprecated
>> "%0 %select{is|%select{is|was}3}1 deprecated"
>> "%select{| %select{on|in}3 %2%select{| %4}3}1"
>> availability_deprecated_msg
>> "%0 %select{is|%select{is|was}3}1 deprecated"
>> "%select{| %select{on|in}3 %2%select{| %4}3}1: %5"
>> availability_deprecated_rename
>> "%0 %select{is|%select{is|was}3}1 deprecated"
>> "%select{| %select{on|in}3 %2%select{| %4}3}1: renamed to '%5'"
>> parameter_curry_syntax_removed
>> "curried function declaration syntax will be removed in a future "
>> "version of Swift; use a single parameter list"
>>
>>
>> Unsupported:
>> warning_parallel_execution_not_supported
>> "parallel execution not supported; falling back to serial execution"
>> unsupported_synthesize_init_variadic
>> "synthesizing a variadic inherited initializer for subclass %0 is "
>> "unsupported"
>>
>>
>> Stylistic/Pedantic/Cleanliness:
>> pbd_never_used_stmtcond
>> "value %0 was defined but never used; consider replacing "
>> "with boolean test"
>> pbd_never_used
>> "initialization of %select{variable|immutable value}1 %0 was never used"
>> "; consider replacing with assignment to '_' or removing it"
>> capture_never_used
>> "capture %0 was never used",
>> variable_never_used
>> "%select{variable|immutable value}1 %0 was never used; "
>> "consider replacing with '_' or removing it"
>> variable_never_mutated
>> "%select{variable|parameter}1 %0 was never mutated; "
>> "consider changing to 'let' constant"
>> variable_never_read
>> "%select{variable|parameter}1 %0 was written to, but never read"
>> expression_unused_result
>> "result of call to %0 is unused"
>> expression_unused_init_result
>> "result of initializer is unused", ())
>> expression_unused_result_message
>> "result of call to %0 is unused: %1"
>> expression_unused_result_nonmutating
>> "result of call to non-mutating function %0 is unused; "
>> "use %1 to mutate in-place"
>> expression_unused_optional_try
>> "result of 'try?' is unused"
>> non_trailing_closure_before_default_args
>> "closure parameter prior to parameters with default arguments will "
>> "not be treated as a trailing closure"
>> parameter_extraneous_double_up
>> "extraneous duplicate parameter name; %0 already has an argument "
>> "label"
>> parameter_extraneous_empty_name
>> "extraneous '_' in parameter: %0 has no keyword argument name"
>> escaped_parameter_name
>> "keyword '%0' does not need to be escaped in argument list"
>>
>>
>> CodeSmell/StrongStylisticHints:
>> guard_always_succeeds
>> "'guard' condition is always true, body is unreachable"
>> warn_unqualified_access
>> "use of %0 treated as a reference to %1 in %2 %3"
>> var_pattern_didnt_bind_variables
>> "'%0' pattern has no effect; sub-pattern didn't bind any variables"
>> type_inferred_to_undesirable_type
>> "%select{variable|constant}2 %0 inferred to have type %1, "
>> "which may be unexpected"
>> no_throw_in_try
>> "no calls to throwing functions occur within 'try' expression"
>> no_throw_in_do_with_catch
>> "'catch' block is unreachable because no errors are thrown in 'do' block"
>> required_initializer_override_keyword
>> "'override' is implied when overriding a required initializer"
>> if_always_true
>> "'if' condition is always true"
>> while_always_true
>> "'while' condition is always true"
>> warn_protocol_witness_optionality
>> "%select{type|result|parameter|parameters|"
>> "result and parameters}0 of %1 %select{has|has|has|have|have|}0"
>> " different optionality than expected by protocol %2"
>> optional_req_nonobjc_near_match
>> "non- at objc %select{initializer %1|method %1|property %1|subscript}0 "
>> "cannot satisfy optional requirement of @objc protocol %2"
>> override_unnecessary_IUO
>> "overriding %0 parameter of type %1 with implicitly unwrapped optional "
>> "type %2",
>> override_unnecessary_result_IUO
>> "overriding %0 optional result type %1 with implicitly unwrapped "
>> "optional type %2",
>> inject_forced_downcast, sema_tce, none,
>> "treating a forced downcast to %0 as optional will never produce 'nil'"
>> recursive_accessor_reference, tce_sema, none,
>> "attempting to %select{access|modify}1 %0 within its own "
>> "%select{getter|setter}1",
>> store_in_willset, tce_sema, none,
>> "attempting to store to property %0 within its own willSet, which is "
>> "about to be overwritten by the new value",
>> isa_is_always_true
>> "'%0' test is always true",
>> conditional_downcast_coercion
>> "conditional cast from %0 to %1 always succeeds"
>> downcast_to_unrelated, sema_tcc, none,
>> "cast from %0 to unrelated type %1 always fails"
>> forced_downcast_noop
>> "forced cast of %0 to same type has no effect"
>> forced_downcast_coercion
>> "forced cast from %0 to %1 always succeeds; did you mean to use 'as'?"
>> extraneous_default_args_in_call
>> "call to %0 has extraneous arguments that could use defaults"
>> unreachable_code
>> "will never be executed"
>> unreachable_code_after_stmt
>> "code after '%select{return|break|continue|throw}0' will never "
>> "be executed"
>> unreachable_case
>> "%select{case|default}0 will never be executed"
>> switch_on_a_constant
>> "switch condition evaluates to a constant"
>> integer_conversion_overflow_warn
>> "integer overflows when converted from %0 to %1"
>> integer_literal_overflow_warn
>> "integer literal overflows when stored into %0"
>> trailing_closure_excess_newlines
>> "trailing closure is separated from call site by multiple newlines"
>> lex_nul_character, lexing, none
>> "nul character embedded in middle of file"
>> unindented_code_after_return
>> "expression following 'return' is treated as an argument of "
>> "the 'return'"
>> lex_editor_placeholder_in_playground
>> "editor placeholder in source file"
>>
>>
>> Attributes:
>> attr_availability_unknown_platform
>> "unknown platform '%0' for attribute '%1'"
>> attr_warn_unused_result_expected_name
>> "expected parameter 'message' or 'mutable_variant'"
>> attr_warn_unused_result_duplicate_parameter
>> "duplicate '%0' parameter; previous value will be ignored"
>> attr_warn_unused_result_unknown_parameter
>> "unknown parameter '%0' in 'warn_unused_result' attribute"
>> attr_migration_id_expected_name
>> "expected parameter 'pattern'"
>> attr_migration_id_unknown_parameter
>> "unknown parameter '%0' in '_migration_id' attribute"
>> attr_migration_id_duplicate_parameter
>> "duplicate '%0' parameter; previous value will be ignored"
>> invalid_swift_name_method
>> "too %select{few|many}0 parameters in swift_name attribute (expected %1; "
>> "got %2)"
>>
>> Availability:
>> availability_query_useless_min_deployment
>> "unnecessary check for '%0'; minimum deployment target ensures guard "
>> "will always be true"
>> availability_query_useless_enclosing_scope
>> "unnecessary check for '%0'; enclosing scope ensures guard "
>> "will always be true"
>>
>> And the below I'm either struggling to think about how to categorize them
>> (perhaps no category at first), or un-familiar with what they're targeting
>> warning_from_clang:
>> "%0"
>> could_not_rewrite_bridging_header, none, none,
>> "failed to serialize bridging header; "
>> "target may not be debuggable outside of its original project"
>> omit_needless_words
>> "%0 could be named %1 [-Womit-needless-words]"
>> unused_compiler_version_component
>> "the second version component is not used for comparison"
>> unknown_build_config
>> "unknown %0 for build configuration '%1'"
>> sema_import_current_module
>> "this file is part of module %0; ignoring import"
>> sema_import_current_module_with_file
>> "file '%0' is part of module %1; ignoring import"
>> access_control_member_more
>> "declaring %select{PRIVATE|an internal|a public}0 %1 for "
>> "%select{a private|an internal|PUBLIC}2 %3"
>> access_control_ext_member_more
>> "declaring %select{PRIVATE|an internal|a public}0 %1 in "
>> "%select{a private|an internal|PUBLIC}2 extension"
>> emit_reference_dependencies_without_primary_file
>> "ignoring -emit-reference-dependencies (requires -primary-file)"
>> warning_no_such_sdk
>> "no such SDK: '%0'"
>> warn_cannot_stat_input
>> "unable to determine when '%0' was last modified: %1"
>> warning_unnecessary_repl_mode
>> "unnecessary option '%0'; this is the default for '%1' "
>> "with no input files"
>> incremental_requires_output_file_map
>> "ignoring -incremental (currently requires an output file map)"
>> incremental_requires_build_record_entry
>> "ignoring -incremental; output file map has no master dependencies "
>> "entry (\"%0\" under \"\")"
>>
>> I haven’t gotten to how to expose this to the user, and I’ll defer to the community for suggestions in that area.
>
> Just an FYI: We have also talked about performance related warnings at the SIL level (that could potentially be a hard error). We do not have any such thing implemented right now, but keep it in mind.
>
> Michael
>
>>
>>
>> _______________________________________________
>> swift-dev mailing list
>> swift-dev at swift.org <mailto:swift-dev at swift.org>
>> https://lists.swift.org/mailman/listinfo/swift-dev
>
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