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HH_CLIENT(1) General Commands Manual HH_CLIENT(1)

NAME

hh_client - Interface to Hack language typechecker

SYNOPSIS

hh_client [MODE] [OPTIONS] [DIRECTORY]

DESCRIPTION

hh_client(1) is an interface to a static analysis tool which is what enforces most of the Hack language's type system. Code must pass validation of this tool in order to be considered valid code in the Hack language.

There are several possible MODEs for hh_client(1) (see below). By default, it will invoke the check mode, with the current directory as DIRECTORY. These are reasonable defaults, meaning that most users can simply invoke the command as

hh_client


with no arguments to get a list of type errors across the entire
    project.


All of the MODEs accept a DIRECTORY as an optional
    final argument. This denotes the project upon which to operate.
    hh_client(1) walks up the filesystem from the DIRECTORY until
    it finds a file called .hhconfig and then operates on the body of
    Hack language code rooted in this directory. If no DIRECTORY is
    specified, it uses the current directory by default. This means you may run
    hh_client(1) in any subdirectory of your project and get type errors
    for the whole project without ever specifying a DIRECTORY
  explicitly.


hh_client(1) implements very little logic itself, but
    rather serves as an interface to the hh_server(1) daemon. The server
    will automatically be started and restarted as needed.








MODES




check


The default MODE if none is specified. With no
    OPTIONS specified, it prints a list of type errors on standard
    output, or prints "No errors!" if there were none.


Many OPTIONS affect the output of check mode,
    sometimes causing it to do completely different things. (Those can be
    considered "sub-modes" of check mode.) Many of these
    options are undergoing considerable revision and so are not documented here;
    read the source for a full list.


Widely-useful OPTIONS for check mode include:





  

  
Sub-mode which prints out information on what parts of FILE are
      actually typechecked and which are not. Due to Hack's partial mode and PHP
      interoperability, the type system may not know the types of parts of a
      program. In this case, it trusts the programmer and carries on. The
      --color mode prints out a file with ANSI terminal colors, where
      green code is actually fully checked, and red code cannot be fully checked
      due to such missing type information.
    

  

  

  
Prints information about hh_client(1) and its command line options,
      and then exits. Many of the options described there are experimental,
      especially if they are not described in this man page.
    

  

  

  
Prints output in the format expected by a specific editor. Valid values of
      EDITOR are emacs and vim. For usage by other tools,
      try --json instead.
    

  

  

  
Prints output in a JSON format intended for machine consumption, instead
      of the output intended for human consumption that is output by default.
    

  

  

  
If the typechecker daemon is busy, try NUM times to connect to it
      before giving up. Set NUM to 0 to disable retries if the server is
      not immediately available.
    

  

  

  
Prints human-readable type error information to standard out and then
      exits. The default sub-mode of check if none is specified. This
      output is not intended for usage by tools, but only for human consumption.
      For output intended for tool usage, see the --json and/or
      --from options.
    

  

  

  
Prints the current client version, including build ID and build date, and
      then exits.
    

  

  

  
Autocompletes text on STDIN where the cursor is replaced with
      AUTO332. Returns a newline-separated list.
    

  

  
  
Fuzzy search symbol definitions for STRING. Returns a
      newline-separated list.
    

  








start


Explicitly starts the hh_server(1) daemon if it is not
    already running. This is not normally necessary, since check mode
    will start it as needed if it is not running.








stop


Explicitly stops the hh_server(1) daemon if it is running.
    This is not normally necessary, since the daemon will exit if it has not
    been used for an extended period of time.








restart


Explicitly stops and then starts again the hh_server(1)
    daemon. Fails if the daemon is not currently running. Restarting the daemon
    is not normally necessary, since it updates its state in the background, and
    hh_client(1) will restart it automatically if the typechecker
    binaries have been updated.










EXIT STATUS


For check mode in the --status sub-mode,
    hh_client(1) returns 0 if there are no type errors, and non-zero
    otherwise.


Exit statuses for any other invocations are currently undefined
    and subject to change.








ENVIRONMENT



  

  
Used in combination with the path to the project root in order to locate
      the socket for communicating with the running hh_server(1) daemon.
      Normally set by your login environment, but may be unset in some
      nonstandard setups.
    

  








FILES



  
.hhconfig

  
When determining where the project root is in order to figure out what
      files to actually typecheck, hh_client(1) walks up the directory
      tree from the specified DIRECTORY until it finds this file. The set
      of files recursively included in the directory with the .hhconfig
      file is the set of files typechecked.
    

  

  
/tmp/hh_server_$USER/

  
The client looks inside this directory for sockets to communicate with the
      hh_server(1) daemon. The sockets are named based on a hash of the
      absolute path of the project root.
    

  








BUGS


The Hack language is part of the HHVM project. Known bugs can be
    found at that tracker, and new ones should be reported there as well:
    https://github.com/facebook/hhvm/issues








SEE ALSO


hh_server(1), hackificator(1), hack_remove_soft_types(1).
  

  http://docs.hhvm.com/hack/typechecker/setup
  

  http://www.hacklang.org/