path: root/lib/dialyzer/RELEASE_NOTES

==============================================================================
	Major features, additions and changes between Dialyzer versions
		(in reversed chronological order)
==============================================================================

Version 2.2.0 (in Erlang/OTP R13B04)
------------------------------------
 - Much better support for opaque types (thanks to Manouk Manoukian).
 - Added support for recursive types (experimental).
 - Added support for parameterized modules.
 - Dialyzer now warns when -specs state that a function returns some type
   when in fact it does not.
 - Added --no_native (-nn) option so that the user can bypass the native code
   compilation that dialyzer heuristically performs when dialyzing many files.
 - Fixed minor bug in the dialyzer script allowing the --wx option to bring
   up the wx-based GUI regardless of its placement in the options list.
 - Options --apps and -Wrace_conditions, which were added in the previous
   version, are now properly documented in the manual.

Version 2.1.0 (in Erlang/OTP R13B03)
------------------------------------
 - Dialyzer can statically detect some kinds of data races in Erlang programs.
   Use the new option -Wrace_conditions to enable the race analysis.
   The static analysis technique is described in a paper available at:
     http://www.it.uu.se/research/group/hipe/dialyzer/publications/races.pdf
 - Added support for packages (thanks to Maria Christakis).
 - There has been a major change in the default mode of Dialyzer.
   Previously, the default mode was the GUI, while now it is the command
   line. As a result of this change, it is now possible to analyze a set of
   files/dirs with the command:
	dialyzer file1 ... fileN
   In other words, the -c (--command-line) option is no longer necessary,
   though it will be retained for some time for backwards compatibility.
   To start dialyzer's GUI use either of the following commands:
	dialyzer --gui         %% for the old gs-based GUI
	dialyzer --wx          %% for the new wx-based GUI (where available)
 - There is a new option --apps which allows the user to easily refer to
   Erlang/OTP applications and include them in the analysis or in the
   building of the PLT.  For example, we recommend building the PLT with:
	dialyzer --build_plt --apps erts kernel stdlib mnesia ...
   The new option can also take absolute file names as well as applications.
   Note that the application versions that will be included in the PLT are
   those that correspond to the Erlang/OTP system which is used.
 - Dialyzer has a new wxWidgets based GUI (thanks to Elli Fragkaki)
   for platforms where the wx application is available.

Version 2.0.0 (in Erlang/OTP R13B02)
------------------------------------
 - There is a major addition to the capabilities of dialyzer, worthy
   of bumping the version number. Starting with this version, dialyzer
   not only accepts but also properly processes remote types (i.e.,
   types of the form ModuleName:TypeName()). Previous dialyzer
   versions only accepted this notation in -type and -spec
   declarations, but effectively ignored its information by mapping
   remote types to the type any(). In contrast, starting with this
   version, remote types are used in the analysis and are also stored
   in the PLTs. (This addition changes the format of PLTs and requires
   rebuilding any PLTs created by an older dialyzer version.)
   Note that dialyzer will complain and abort the analysis of a set of
   modules if it needs to process a remote type without a definition
   (either because the module does not include a definition of the
   type or the module is not included in the analysis). We may relax
   this restriction in a future version.
 - Fixed minor issue with dialyzer:run/1 crashing (upon its return)
   when used for adding type information to an existing PLT.
 - Fixed minor but quite annoying issues in dialyzer's GUI.

Version 1.9.2 (in Erlang/OTP R13B01)
------------------------------------
 - Fixed problem with type inference going into an infinite loop when
   analyzing a strongly connected component of functions that do not
   return but also contain an erroneous call which makes them fail and
   be assigned the type none() instead of the type unit().
 - More accurate type information for some BIFs and library files.
 - Introduced boolean() as the `official' name for the type which was so
   far known as bool(). The latter is still accepted as well as boolean()
   but results in a warning from the compiler; converting the code to use
   the new name is strongly encouraged.

Version 1.9.1 (in Erlang/OTP R13B)
----------------------------------
 - Contains the changes described below (R13A) but also:
    - Has better handling of opaque types.
    - The handling of UFT segments of bitstreams has been significantly
      strengthened and revised.  In all probability, now it is correct.

Version 1.9.0 (in Erlang/OTP R13A)
----------------------------------
 - The analysis accepts opaque type declarations and detects violations of
   opaqueness of terms of such types.  Starting with R13, many Erlang/OTP
   standard libraries (array, dict, digraph, ets, gb_sets, gb_trees, queue,
   and sets) contain opaque type declarations of their main data types.
   Dialyzer will spit out warnings in code that explicitly depends on the
   structure of these terms.
 - Added support for handling UTF segments in bitstreams and for detecting
   obvious type errors in these segments.
   Warning: This code is not terribly tested -- not surprising since this is
   a new language feature of R13.
 - Strengthened the discrepancy identification when testing for equality and
   matching between terms of different types.  This detects more bugs in code.
 - Added warning for M:F(...) calls where M is not a module term and F is not
   an atom.  Previously, such calls where found to fail but the reason for
   the failure was not reported.
 - Added a convenient shorthand for the --no_check_plt option (-n).
 - Added the --dump_callgraph option for dumping the callgraph of all files
   that are analyzed into a specified file.  The callgraph either be dumped
   in raw format, in .dot format, or converted to a .ps (postscript) file.
   Note that in large callgraphs the generated postscript file might not be
   interpretable by Ghostview.
   (Thanks to Ilya Khlopotov for the initial version of this functionality.)

Version 1.8.3 (in Erlang/OTP R12B-5)
------------------------------------
 - Added the --no_check_plt option that makes the startup time faster
   when working with PLTs that are known not to change.
 - Changed the phrasing of some warnings so that they do not cause confusion
   to some users and correspond better to reality.

Version 1.8.2 (in Erlang/OTP R12B-4)
------------------------------------
 - The return type of the Erlang interface dialyzer:run/1 has changed
   to only return a list of warnings. If something goes wrong dialyzer
   dies with an exception.
 - The handling of the PLT has changed. Please consult the manual for
   the changes.

Version 1.8.0 (in Erlang/OTP R12B-2)
------------------------------------
 - Dialyzer's analysis is from now on exclusively based on success typings.
   In particular, support for options --old_style and --dataflow has been
   discontinued.
 - Better and more aggressive handling of type information in records.
 - Dialyzer has a new warning option -Wunmatched_returns which warns for
   function calls that ignore the return value.
   This catches many common programming errors (e.g. calling file:close/1
   and not checking for the absense of errors), interface discrepancies
   (e.g. a function returning multiple values when in reality the function
   is void and only called for its side-effects), calling the wrong function
   (e.g. io_lib:format/1 instead of io:format/1), and even possible
   performance defects (e.g. unnecessarily constructing a list using a list
   comprehension instead of using lists:foreach/2).
   Whenever a function returns a single atomic value (e.g. 'ok' or pid()),
   the warning is suppressed. This allows for "void" functions (returning
   a single atom like 'ok') or for calls to certain builtins like spawn.
   Because not all calls which ignore the return value are discrepancies,
   the option is off by default and has to be explicitly requested by the user.
   But we recommend it nevertheless.
 - Some warning options (-Wno_comp, -Wno_guards, -Wno_unsafe_beam, etc.)
   which could be used when analyzing bytecode produced by an old BEAM
   compiler have been removed.

Version 1.7.2 (in Erlang/OTP R12B-1)
------------------------------------
 - The Erlang interface of Dialyzer returns warnings tagged by their type.

Version 1.7.1 (in Erlang/OTP R12B-0)
------------------------------------
 - Use of success typings is now default, is robust and detects significantly
   more errors than in previous versions.
 - Dialyzer accepts and takes into account type information in record
   declarations and in contracts -- see related paper in Erlang'07 workshop.
   Various OTP applications (e.g. stdlib and kernel) are partially annotated
   with appropriate contracts specifying types information for their functions.
 - The type previously known as unit() has been renamed to no_return().
   Its use in a contract as the return type of a function now silences off
   the "function has no local return" dialyzer warning without use of the
   corresponding option.

Version 1.7.0 (in Erlang/OTP R11B-5)
------------------------------------ 
 - Dialyzer can now use success typings to find discrepancies. As a
   consequence significantly more discrepancies are detected. The downside
   is that the analysis takes about 2 to 2.5 times longer than in previous
   versions, and may also result in some warnings that might be harder to
   interpret even though they are correct. This has been a major change, 
   worth of increasing the version number.
   New command-line options:
   --succ_typings                        Use the success typings analysis.
   --dataflow     (default)              Use the previous analysis.   
 - The new type unit() has been introduced to handle the return type of
   non-terminating functions such as servers.
 - Dialyzer's code server uses a compressed representation and the analysis
   requires significantly less memory than in previous versions.

Version 1.6.0 (in Erlang/OTP R11B-4)
------------------------------------
 - Dialyzer (in the modes where either source or BEAM code which contains
   debug_info is analyzed) spits out line information for all discrepancies.
   This has been a major change, worth of increasing the version number.
     We warn users that *considerably* more discrepancies are identified 
     by this version of Dialyzer compared with previous ones.  If warnings
     generated by previous versions of Dialyzer are preferable for some
     applications, the command line option --old_style can be employed.
 - Dialyzer handles term comparison operators more precisely and is able to
   identify more discrepancies in 'if' or 'case' statements with comparisons.
 - Dialyzer has more precise type information for many standard OTP functions.

Version 1.5.1 (in Erlang/OTP R11B-3)
------------------------------------
 - Added the option --check_init_plt that can be used to force the re-building 
   of the initial plt for installed systems.
 - Fixed some bugs in the handling of guards in the dataflow analysis after
   a report from Fredrik Thulin.
 - Cleaned up the error handling and the interface and now Dialyzer has an 
   Erlang interface.
 - Building the PLT using success typings is considerably faster than in 1.5.0.
 - Added option --verbose which makes Dialyzer a bit more verbose.

Version 1.5.0 (in Erlang/OTP R11B-2)
------------------------------------
 - Dialyzer's building of PLT is based on a different type inference algorithm.
   More specifically, Dialyzer uses inferrence of refined success typings to
   infer function prototypes.  As a result, Dialyzer bases its analysis on a
   significantly more powerful basis and thus is able to detect more
   discrepancies.  The downside is that building the PLT is a considerably
   slower process.  We will work on improving that.
 - Dialyzer takes into account the BEAM compiler directive
	-compile({nowarn_unused_function, {F,A}}).
   and then suppresses the warning that function F/A will never be called.
 - Dialyzer's default initial PLT now also includes "mnesia".

Version 1.4.2 (in Erlang/OTP R11B-1)
------------------------------------
 - Speed up changes and small bug fixes.

Version 1.4.1 (in Erlang/OTP R11B-0)
------------------------------------
 - Dialyzer is officially part of Erlang/OTP as a library application.
 - Instead of being a shell script, "dialyzer" is an executable (generated
   by a C program -- thanks to Bjorn Gustavsson), and works similarly to "erlc".
   As a side-effect of this change, Dialyzer now also works on Windows.

Version 1.4.0
-------------
 - Changes for Dialyzer to work with Erlang/OTP R10B-10
 - Dialyzer's analysis is significantly faster as it uses a global function
   call-graph for obtaining type signatures for all analyzed functions
 - ...
 - Many more other changes; in fact too many to mention here.

Version 1.3.1 (mostly internal)
-------------
 - Small changes for Dialyzer to work with Erlang/OTP R10B-5.
 - Modified setup script for execution under Cygwin (patch by Vlad Dumitrescu)
 - Added command line option --no_warn_on_inline
 - Fixed a small buglet in the analysis; this affected one of HiPE's files
 - Dialyzer now explicitly warns when modules with the same name
   but from different dirs are being analyzed (contribution by Ulf Wiger)

Version 1.3.0
-------------
 - Requires the presence of an Erlang/OTP R10B-4 system.
 - Dialyzer is significantly (approx 40%) faster since it now uses 'ets'
   rather than 'dets' for its PLT.
 - Slightly improved the precision of the analysis.
 - Fixed a number of false positives that Dialyzer 1.2.0 was spitting out.
 - In the GUI version, Dialyzer now reports the list of modules that should
   be included in the modules to analyze in order to possibly improve
   the accuracy of the reported results.
 - Some more information is displayed when calling a function or closure
   with arguments of the wrong type.
 - The record guard now allows discrepancies involving tuples that are known
   to be records to be displayed as #rec{} rather than {'rec',_,...,_}
 - Added -q option which makes the command-line version of Dialyzer
   a bit more silent.

Version 1.2.0
-------------
 - Dialyzer works with the open source and commercial versions of Erlang/OTP
   R10B-2 on all platforms (i.e., HiPE support is not a prerequisite anymore).
 - Whenever a .beam file contains abstract code (i.e., has been compiled
   with the +debug_info option), the analysis starts from this code rather
   than from BEAM bytecode -- this makes the results identical to those
   obtained by analysis starting from source code.
   (This is a contribution from Bjorn Gustavsson - Thanks!)
 - Added -pa command line option for easier handling of -include_lib()
   directives in source code.
 - Includes all changes added in v1.1.1; see below.  The "Add Recursively"
   functionality is also available in the command-line mode (-r option).

Version 1.1.1 (internal, not released to the masses :-)
-------------
 - The command-line mode of Dialyzer spits discrepancies in stdout
   by default and returns a numeric value indicating its exit status.
 - Fixed problems using the shell script on Solaris machines.
 - Fixed small inconsistencies in Dialyzer's documentation and help.
 - Added "Add Recursively" button contributed by Martin Bjorklund (thanks!).

Version 1.1.0
-------------
 - Dialyzer works with the open source version of Erlang/OTP R10B-1 (on
   platforms where HiPE support is available) and it does not require
   installation of a customized Erlang/OTP system anymore.
 - Dialyzer comes with an extensive command-line interface, in addition
   to an enhanced GUI.
 - Analysis can start from source code (through Core Erlang) as well as
   from BEAM bytecode.
 - Dialyzer finds considerably more discrepancies in Erlang code than
   previous versions.
 - Added ability to selectively turn on/off different warning categories.

Version 1.0.1
-------------
 - Fixed major bug of v1.0.0 which caused the analysis to stop prematurely
   (i.e., without properly reaching fixpoint) when analyzing more than one
   module.  This did not affect correctness of the results, but lost many
   opportunities to detect discrepancies.
 - Performance improvements in the analysis.

Version 1.0.0
-------------
 Initial Dialyzer version: Analysis starts from BEAM bytecode only and 
 only a GUI version is available. Dialyzer reports discrepancies in the
 use of the "sequential" part of Erlang. To be used, Dialyzer requires
 the presence of a specific snapshot of Erlang/OTP which can be obtained
 from Dialyzer's homepage.