dialyzer - Dialyzer, a DIscrepancy AnaLYZer for ERlang
programs.
Dialyzer is a static analysis tool that identifies software
discrepancies, such as definite type errors, code that has become dead or
unreachable because of programming error, and unnecessary tests, in single
Erlang modules or entire (sets of) applications.
Dialyzer starts its analysis from either debug-compiled BEAM
bytecode or from Erlang source code. The file and line number of a
discrepancy is reported along with an indication of what the discrepancy is
about. Dialyzer bases its analysis on the concept of success typings, which
allows for sound warnings (no false positives).
Dialyzer has a command-line version for automated use. This
section provides a brief description of the options. The same information
can be obtained by writing the following in a shell:
dialyzer --help
For more details about the operation of Dialyzer, see section
Using Dialyzer from the GUI in the User's Guide.
Exit status of the command-line version:
- 0:
- No problems were found during the analysis and no warnings were
emitted.
- 1:
- Problems were found during the analysis.
- 2:
- No problems were found during the analysis, but warnings were
emitted.
Usage:
dialyzer [--add_to_plt] [--apps applications] [--build_plt]
[--check_plt] [-Ddefine]* [-Dname] [--dump_callgraph file]
[files_or_dirs] [--fullpath] [--get_warnings] [--gui] [--help]
[-I include_dir]* [--no_check_plt] [--no_indentation] [--no_native]
[--no_native_cache] [-o outfile] [--output_plt file] [-pa dir]*
[--plt plt] [--plt_info] [--plts plt*] [--quiet] [-r dirs]
[--raw] [--remove_from_plt] [--shell] [--src] [--statistics]
[--verbose] [--version] [-Wwarn]*
Note:
* denotes that multiple occurrences of the option are possible.
Options:
- --add_to_plt:
- The PLT is extended to also include the files specified with -c and
-r. Use --plt to specify which PLT to start from, and
--output_plt to specify where to put the PLT. Notice that the
analysis possibly can include files from the PLT if they depend on the new
files. This option only works for BEAM files.
- --apps
applications:
- This option is typically used when building or modifying a PLT as in:
dialyzer --build_plt --apps erts kernel stdlib mnesia ...
to refer conveniently to library applications corresponding to the
Erlang/OTP installation. However, this option is general and can also be
used during analysis to refer to Erlang/OTP applications. File or directory
names can also be included, as in:
dialyzer --apps inets ssl ./ebin ../other_lib/ebin/my_module.beam
- --build_plt:
- The analysis starts from an empty PLT and creates a new one from the files
specified with -c and -r. This option only works for BEAM
files. To override the default PLT location, use --plt or
--output_plt.
- --check_plt:
- Check the PLT for consistency and rebuild it if it is not up-to-date.
- -Dname (or
-Dname=value):
- When analyzing from source, pass the define to Dialyzer. (**)
- --dump_callgraph
file:
- Dump the call graph into the specified file whose format is determined by
the filename extension. Supported extensions are: raw, dot,
and ps. If something else is used as filename extension, default
format .raw is used.
- files_or_dirs
(for backward compatibility also as -c files_or_dirs):
- Use Dialyzer from the command line to detect defects in the specified
files or directories containing .erl or .beam files,
depending on the type of the analysis.
- --fullpath:
- Display the full path names of files for which warnings are emitted.
- --get_warnings:
- Make Dialyzer emit warnings even when manipulating the PLT. Warnings are
only emitted for files that are analyzed.
- --gui:
- Use the GUI.
- --help (or
-h):
- Print this message and exit.
- -I
include_dir:
- When analyzing from source, pass the include_dir to Dialyzer.
(**)
- --no_check_plt:
- Skip the PLT check when running Dialyzer. This is useful when working with
installed PLTs that never change.
- --no_indentation:
- Do not insert line breaks in types, contracts, and Erlang Code when
formatting warnings.
- --no_native
(or -nn):
- Bypass the native code compilation of some key files that Dialyzer
heuristically performs when dialyzing many files. This avoids the
compilation time, but can result in (much) longer analysis time.
- --no_native_cache:
- By default, Dialyzer caches the results of native compilation in directory
$XDG_CACHE_HOME/erlang/dialyzer_hipe_cache. XDG_CACHE_HOME
defaults to $HOME/.cache. Use this option to disable caching.
- -o outfile (or --output
outfile):
- When using Dialyzer from the command line, send the analysis results to
the specified outfile rather than to stdout.
- --output_plt
file:
- Store the PLT at the specified file after building it.
- -pa dir:
- Include dir in the path for Erlang. This is useful when analyzing
files that have -include_lib() directives.
- --plt
plt:
- Use the specified PLT as the initial PLT. If the PLT was built during
setup, the files are checked for consistency.
- --plt_info:
- Make Dialyzer print information about the PLT and then quit. The PLT can
be specified with --plt(s).
- --plts
plt*:
- Merge the specified PLTs to create the initial PLT. This requires that the
PLTs are disjoint (that is, do not have any module appearing in more than
one PLT). The PLTs are created in the usual way:
dialyzer --build_plt --output_plt plt_1 files_to_include
...
dialyzer --build_plt --output_plt plt_n files_to_include
They can then be used in either of the following ways:
dialyzer files_to_analyze --plts plt_1 ... plt_n
dialyzer --plts plt_1 ... plt_n -- files_to_analyze
Notice the -- delimiter in the second case.
- --quiet (or
-q):
- Make Dialyzer a bit more quiet.
- -r dirs:
- Same as files_or_dirs, but the specified directories are searched
recursively for subdirectories containing .erl or .beam
files in them, depending on the type of analysis.
- --raw:
- When using Dialyzer from the command line, output the raw analysis results
(Erlang terms) instead of the formatted result. The raw format is easier
to post-process (for example, to filter warnings or to output HTML
pages).
- --remove_from_plt:
- The information from the files specified with -c and -r is
removed from the PLT. Notice that this can cause a reanalysis of the
remaining dependent files.
- --shell:
- Do not disable the Erlang shell while running the GUI.
- --src:
- Override the default, which is to analyze BEAM files, and analyze starting
from Erlang source code instead.
- --statistics:
- Print information about the progress of execution (analysis phases, time
spent in each, and size of the relative input).
- --verbose:
- Make Dialyzer a bit more verbose.
- --version (or
-v):
- Print the Dialyzer version and some more information and exit.
- -Wwarn:
- A family of options that selectively turn on/off warnings. (For help on
the names of warnings, use dialyzer -Whelp.) Notice that the
options can also be specified in the file with a -dialyzer()
attribute. For details, see section Requesting or Suppressing Warnings in
Source Files.
Note:
** options -D and -I work both from the command line and in the
Dialyzer GUI; the syntax of defines and includes is the same as that used by
erlc(1).
Warning options:
- -Werror_handling
(***):
- Include warnings for functions that only return by an exception.
- -Wno_behaviours:
- Suppress warnings about behavior callbacks that drift from the published
recommended interfaces.
- -Wno_contracts:
- Suppress warnings about invalid contracts.
- -Wno_fail_call:
- Suppress warnings for failing calls.
- -Wno_fun_app:
- Suppress warnings for fun applications that will fail.
- -Wno_improper_lists:
- Suppress warnings for construction of improper lists.
- -Wno_match:
- Suppress warnings for patterns that are unused or cannot match.
- -Wno_missing_calls:
- Suppress warnings about calls to missing functions.
- -Wno_opaque:
- Suppress warnings for violations of opacity of data types.
- -Wno_return:
- Suppress warnings for functions that will never return a value.
- -Wno_undefined_callbacks:
- Suppress warnings about behaviors that have no -callback attributes
for their callbacks.
- -Wno_unused:
- Suppress warnings for unused functions.
- -Wrace_conditions
(***):
- Include warnings for possible race conditions. Notice that the analysis
that finds data races performs intra-procedural data flow analysis and can
sometimes explode in time. Enable it at your own risk.
- -Wunderspecs
(***):
- Warn about underspecified functions (the specification is strictly more
allowing than the success typing).
- -Wunknown
(***):
- Let warnings about unknown functions and types affect the exit status of
the command-line version. The default is to ignore warnings about unknown
functions and types when setting the exit status. When using Dialyzer from
Erlang, warnings about unknown functions and types are returned; the
default is not to return these warnings.
- -Wunmatched_returns
(***):
- Include warnings for function calls that ignore a structured return value
or do not match against one of many possible return values. However, no
warnings are included if the possible return values are a union of atoms
or a union of numbers.
The following options are also available, but their use is not
recommended (they are mostly for Dialyzer developers and internal
debugging):
- -Woverspecs
(***):
- Warn about overspecified functions (the specification is strictly less
allowing than the success typing).
- -Wspecdiffs
(***):
- Warn when the specification is different than the success typing.
Note:
*** denotes options that turn on warnings rather than turning them off.
Dialyzer can be used directly from Erlang. Both the GUI and the
command-line versions are also available. The options are similar to the
ones given from the command line, see section Using Dialyzer from the
Command Line.
Attribute -dialyzer() can be used for turning off warnings
in a module by specifying functions or warning options. For example, to turn
off all warnings for the function f/0, include the following
line:
-dialyzer({nowarn_function, f/0}).
To turn off warnings for improper lists, add the following line to
the source file:
-dialyzer(no_improper_lists).
Attribute -dialyzer() is allowed after function
declarations. Lists of warning options or functions are allowed:
-dialyzer([{nowarn_function, [f/0]}, no_improper_lists]).
Warning options can be restricted to functions:
-dialyzer({no_improper_lists, g/0}).
-dialyzer({[no_return, no_match], [g/0, h/0]}).
For help on the warning options, use dialyzer -Whelp. The
options are also enumerated, see function gui/1 below
(WarnOpts).
Note:
Warning option -Wrace_conditions has no effect when set in source files.
Attribute -dialyzer() can also be used for turning on
warnings. For example, if a module has been fixed regarding unmatched
returns, adding the following line can help in assuring that no new
unmatched return warnings are introduced:
-dialyzer(unmatched_returns).
format_warning(Msg) -> string()
Types:
Msg = {Tag, Id, msg()}
See run/1.
Get a string from warnings as returned by run/1.
format_warning(Msg, Options) -> string()
Types:
Msg = {Tag, Id, msg()}
See run/1.
Options = [{indent_opt, boolean()}]
Get a string from warnings as returned by run/1.
If indent_opt is set to true (default), line breaks
are inserted in types, contracts, and Erlang code to improve
readability.
gui() -> ok | {error, Msg}
gui(OptList) -> ok | {error, Msg}
Dialyzer GUI version.
OptList :: [Option]
Option :: {files, [Filename :: string()]}
| {files_rec, [DirName :: string()]}
| {defines, [{Macro :: atom(), Value :: term()}]}
| {from, src_code | byte_code}
%% Defaults to byte_code
| {init_plt, FileName :: string()}
%% If changed from default
| {plts, [FileName :: string()]}
%% If changed from default
| {include_dirs, [DirName :: string()]}
| {output_file, FileName :: string()}
| {output_plt, FileName :: string()}
| {check_plt, boolean()},
| {analysis_type, 'succ_typings' |
'plt_add' |
'plt_build' |
'plt_check' |
'plt_remove'}
| {warnings, [WarnOpts]}
| {get_warnings, boolean()}
| {native, boolean()}
%% Defaults to false when invoked from Erlang
| {native_cache, boolean()}
WarnOpts :: error_handling
| no_behaviours
| no_contracts
| no_fail_call
| no_fun_app
| no_improper_lists
| no_match
| no_missing_calls
| no_opaque
| no_return
| no_undefined_callbacks
| no_unused
| race_conditions
| underspecs
| unknown
| unmatched_returns
| overspecs
| specdiffs
plt_info(string()) -> {'ok', [{atom(), any()}]} | {'error',
atom()}
Returns information about the specified PLT.
run(OptList) -> Warnings
Types:
OptList
See gui/0,1.
Warnings
See below.
Dialyzer command-line version.
Warnings :: [{Tag, Id, Msg}]
Tag :: 'warn_behaviour'
| 'warn_bin_construction'
| 'warn_callgraph'
| 'warn_contract_not_equal'
| 'warn_contract_range'
| 'warn_contract_subtype'
| 'warn_contract_supertype'
| 'warn_contract_syntax'
| 'warn_contract_types'
| 'warn_failing_call'
| 'warn_fun_app'
| 'warn_matching'
| 'warn_non_proper_list'
| 'warn_not_called'
| 'warn_opaque'
| 'warn_race_condition'
| 'warn_return_no_exit'
| 'warn_return_only_exit'
| 'warn_umatched_return'
| 'warn_undefined_callbacks'
| 'warn_unknown'
Id = {File :: string(), Line :: integer()}
Msg = msg() -- Undefined