path: root/lib/dialyzer/doc/manual.txt

##----------------------------------------------------------------------------
## File:      doc/manual.txt
## Author(s): Tobias Lindahl <[email protected]>
##	      Kostis Sagonas <[email protected]>
##----------------------------------------------------------------------------

The DIALYZER, a DIscrepany AnaLYZer for ERlang programs.


-----------------------------------------------
--
-- Using Dialyzer from the GUI
--
-----------------------------------------------

Choosing the applications or modules
====================================
In the "File" window you will find a listing of the current directory.
Click your way to the directories/modules you want to add or type the
correct path in the entry.

Mark the directories/modules you want to analyze for discrepancies and
click "Add". You can either add the .beam and .erl-files directly, or
you can add directories that contain these kinds of files. Note that
you are only allowed to add the type of files that can be analyzed in
the current mode of operation (see below), and that you cannot mix
.beam and .erl-files.

The analysis modes
==================
Dialyzer has several modes of analysis. These are controlled by the
buttons in the top-middle part of the main window, under "Analysis Options".

The parameters are:
* File Type:
    - Byte code:
	The analysis starts from .beam bytecode files.
	The files must be compiled with +debug_info.
    - Source code:
	The analysis starts from .erl files.

Controlling the discrepancies reported by the Dialyzer
======================================================
Under the "Warnings" pull-down menu, there are buttons that control
which discrepancies are reported to the user in the "Warnings" window.
By clicking on these buttons, one can enable/disable a whole class of
warnings.  Information about the classes of warnings can be found on
the "Warnings" item under the "Help" menu (at the rightmost top corner).

Running the analysis
====================
Once you have chosen the modules or directories you want to analyze,
click the "Run" button to start the analysis. If for some reason you
want to stop the analysis while it is running, push the "Stop" button.

The information from the analysis will be displayed in the Log and the
Warnings windows.


Include directories and macro definitions
=========================================
When analyzing from source you might have to supply Dialyzer with a
list of include directories and macro definitions (as you can do with
the erlc flags -I and -D). This can be done either by starting Dialyzer
with these flags from the command line as in:

    ./dialyzer -I my_includes -DDEBUG -Dvsn=42 -I one_more_dir

or by adding these explicitly using the "Manage Macro Definitions" or
"Manage Include Directories" sub-menus in the "Options" menu.


Saving the information on the Log and Warnings windows
======================================================
In the "File" menu there are options to save the contents of the Log
and the Warnings window. Just choose the options and enter the file to
save the contents in.

There are also buttons to clear the contents of each window.


Inspecting the inferred types of the analyzed functions
=======================================================
Dialyzer stores the information of the analyzed functions in a
Persistent Lookup Table (PLT). After an analysis you can inspect this
information. In the PLT menu you can choose to either search the PLT
or inspect the contents of the whole PLT. The information is presented
in edoc format.

NOTE: Currently, the information which is displayed is NOT the type
signatures of the functions. The return values are the least upper
bound of the returned type from the function and the argument types
are the least upper bound of the types that the function is called
with. In other words, the argument types is not what the function can
accept, but rather a description of how the function is used.

We are working on finding the type signatures of the function, and
this will (hopefully) be included in a future version of Dialyzer.


-----------------------------------------------
--
-- Using Dialyzer from the command line
--
-----------------------------------------------

Dialyzer also has a command line version for automated use. Below is a
brief description of the list of its options. The same information can
be obtained by writing

	    "dialyzer --help"

in a shell. Please refer to the GUI description for more details on
the operation of Dialyzer.

The exit status of the command line version is:

    0 - No problems were encountered during the analysis and no
        warnings were emitted.
    1 - Problems were encountered during the analysis.
    2 - No problems were encountered, but warnings were emitted.



Usage: dialyzer [--help] [--version] [--shell] [--quiet] [--verbose]
		[-pa dir]* [--plt plt] [--plts plt*] [-Ddefine]*
                [-I include_dir]* [--output_plt file] [-Wwarn]*
                [--src] [--gui | --wx] [files_or_dirs] [-r dirs]
                [--apps applications] [-o outfile]
		[--build_plt] [--add_to_plt] [--remove_from_plt]
		[--check_plt] [--no_check_plt] [--plt_info] [--get_warnings]
                [--no_native] [--fullpath]

Options:
   files_or_dirs (for backwards 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.
   -r dirs
       Same as the previous but the specified directories are searched
       recursively for subdirectories containing .erl or .beam files in
       them, depending on the type of analysis.
   --apps applications
       Option typically used when building or modifying a plt as in:
         dialyzer --build_plt --apps erts kernel stdlib mnesia ...
       to conveniently refer to library applications corresponding to the
       Erlang/OTP installation. However, the option is general and can also
       be used during analysis in order to refer to Erlang/OTP applications.
       In addition, file or directory names can also be included, as in:
         dialyzer --apps inets ssl ./ebin ../other_lib/ebin/my_module.beam
   -o outfile (or --output outfile)
       When using Dialyzer from the command line, send the analysis
       results to the specified outfile rather than to stdout.
   --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 instance, to filter
       warnings or to output HTML pages).
   --src
       Override the default, which is to analyze BEAM files, and
       analyze starting from Erlang source code instead.
   -Dname (or -Dname=value)
       When analyzing from source, pass the define to Dialyzer. (**)
   -I include_dir
       When analyzing from source, pass the include_dir to Dialyzer. (**)
   -pa dir
       Include dir in the path for Erlang (useful when analyzing files
       that have '-include_lib()' directives).
   --output_plt file
       Store the plt at the specified file after building it.
   --plt plt
       Use the specified plt as the initial plt (if the plt was built
       during setup the files will be checked for consistency).
   --plts plt*
      Merge the specified plts to create the initial plt -- requires
      that the plts are disjoint (i.e., 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
      and then can be used in either of the following ways:
        dialyzer files_to_analyze --plts plt_1 ... plt_n
      or:
        dialyzer --plts plt_1 ... plt_n -- files_to_analyze
      (Note the -- delimiter in the second case)
   -Wwarn
       A family of options which selectively turn on/off warnings
       (for help on the names of warnings use dialyzer -Whelp).
   --shell
       Do not disable the Erlang shell while running the GUI.
   --version (or -v)
       Print the Dialyzer version and some more information and exit.
   --help (or -h)
       Print this message and exit.
   --quiet (or -q)
       Make Dialyzer a bit more quiet.
   --verbose
       Make Dialyzer a bit more verbose.
   --build_plt
       The analysis starts from an empty plt and creates a new one from the
       files specified with -c and -r. Only works for beam files.
       Use --plt or --output_plt to override the default plt location.
   --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. Note that the analysis might include
       files from the plt if they depend on the new files.
       This option only works with beam files.
   --remove_from_plt
       The information from the files specified with -c and -r is removed
       from the plt. Note that this may cause a re-analysis of the remaining
       dependent files.
   --check_plt
       Check the plt for consistency and rebuild it if it is not up-to-date.
   --no_check_plt
       Skip the plt check when running Dialyzer. Useful when working with
       installed plts that never change.
   --plt_info
       Make Dialyzer print information about the plt and then quit. The plt
       can be specified with --plt(s).
   --get_warnings
       Make Dialyzer emit warnings even when manipulating the plt. Warnings
       are only emitted for files that are actually analyzed.
   --dump_callgraph file
       Dump the call graph into the specified file whose format is determined
       by the file name extension. Supported extensions are: raw, dot, and ps.
       If something else is used as file name extension, default format '.raw'
       will be used.
   --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 it may result in (much) longer analysis time.
  --fullpath
      Display the full path names of files for which warnings are emitted.
   --gui
       Use the gs-based GUI.
   --wx
       Use the wx-based GUI.

Note:
  * denotes that multiple occurrences of these options are possible.
 ** options -D and -I work both from command-line and in the Dialyzer GUI;
    the syntax of defines and includes is the same as that used by "erlc".

Warning options:
  -Wno_return
     Suppress warnings for functions that will never return a value.
  -Wno_unused
     Suppress warnings for unused functions.
  -Wno_improper_lists
     Suppress warnings for construction of improper lists.
  -Wno_tuple_as_fun
     Suppress warnings for using tuples instead of funs.
  -Wno_fun_app
     Suppress warnings for fun applications that will fail.
  -Wno_match
     Suppress warnings for patterns that are unused or cannot match.
  -Wno_opaque
     Suppress warnings for violations of opaqueness of data types.
  -Wunmatched_returns ***
     Include warnings for function calls which ignore a structured return
     value or do not match against one of many possible return value(s).
  -Werror_handling ***
     Include warnings for functions that only return by means of an exception.
  -Wrace_conditions ***
     Include warnings for possible race conditions.
  -Wbehaviours ***
     Include warnings about behaviour callbacks which drift from the published
     recommended interfaces.
  -Wunderspecs ***
     Warn about underspecified functions
     (those whose -spec is strictly more allowing than the success typing).

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
     (those whose -spec is strictly less allowing than the success typing).
  -Wspecdiffs ***
     Warn when the -spec is different than the success typing.

Note:
   *** Identifies options that turn on warnings rather than turning them off.


-----------------------------------------------
--
-- Using Dialyzer from Erlang
--
-----------------------------------------------

You can also use Dialyzer directly from Erlang. Both the GUI and the
command line version is available. The options are similar to the ones
given from the command line, so please refer to the sections above for
a description of these.

Interface:

dialyzer:gui() -> 'ok'

dialyzer:gui(OptList) -> 'ok'

dialyzer:run(OptList) -> Warnings

Warnings :: [{tag(), id(), msg()}]
tag()    ::  'warn_return_no_exit' | 'warn_return_only_exit' | 'warn_not_called'
           | 'warn_non_proper_list' | 'warn_fun_app' | 'warn_matching'
           | 'warn_failing_call' | 'warn_contract_types'
           | 'warn_contract_syntax' | 'warn_contract_not_equal'
           | 'warn_contract_subtype' | 'warn_contract_supertype'
id()     :: {File :: string(), Line :: integer()}
msg()    :: Undefined

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()}
	  | {analysis_type,  'succ_typings' | 'plt_add' |
                             'plt_build' | 'plt_check' | 'plt_remove'}
	  | {warnings,       [WarnOpts]}

WarnOpts :: no_return
	  | no_unused
	  | no_improper_lists
	  | no_fun_app
	  | no_match
	  | no_fail_call
	  | unmatched_returns
	  | error_handling

dialyzer:format_warning({tag(), id(), msg()}) -> string()
 
Returns a string representation of the warnings as returned by dialyzer:run/1.

dialyzer:plt_info(string()) -> {'ok', [{atom(), any()}]} | {'error', atom()}

Returns information about the specified plt.

-----------------------------------------------
--
-- More on the Persistent Lookup Table (PLT)
--
-----------------------------------------------

The persistent lookup table, or PLT, is used to store the result of an
analysis. The PLT can then be used as a starting point for later
analyses. It is recommended to build a PLT with the otp applications
that you are using, but also to include your own applications that you
are using frequently.

The PLT is built using the --build_plt option to dialyzer. The
following command builds the recommended minimal PLT for OTP.

   dialyzer --build_plt --apps erts kernel stdlib mnesia

Dialyzer will look if there is an environment variable called
$DIALYZER_PLT and place the PLT at this location. If no such variable
is set, Dialyzer will place the PLT at $HOME/.dialyzer_plt. The
placement can also be specified using the --plt, or --output_plt
options.

You can also add information to an existing plt using the --add_to_plt
option. Suppose you want to also include the compiler in the PLT and
place it in a new PLT, then give the command

  dialyzer --add_to_plt --apps compiler --output_plt my.plt

Then you would like to add your favorite application my_app to the new
plt.

  dialyzer --add_to_plt --plt my.plt -r <path>/my_app/ebin

But you realize that it is unnecessary to have compiler in this one.

  dialyzer --remove_from_plt --plt my.plt ---apps compiler

Later, when you have fixed a bug in your application my_app, you want
to update the plt so that it will be fresh the next time you run
Dialyzer, run the command

  dialyzer --check_plt --plt my.plt

Dialyzer will then reanalyze the files that have been changed, and the
files that depend on these files. Note that this consistency check
will be performed automatically the next time you run Dialyzer with
this plt. The --check_plt option is merely for doing so without doing
any other analysis.

-----------------------------------------------
--
-- Feedback & bug reports
--
-----------------------------------------------

At this point, we very much welcome user feedback (even wish-lists!).
If you notice something weird, especially if the Dialyzer reports any
discrepancy that is a false positive, please send an error report
describing the symptoms and how to reproduce them to:

	[email protected], [email protected]