Installation Instructions
-------------------------

Please follow the instructions below to build and install Taskwarrior from
source.


Dependencies
------------

You will need the CMake 3.0+ build system installed in order to build Taskwarrior
from source. More information on CMake can be obtained at https://cmake.org

You will also need:
  - make

You will need a C++ compiler that supports full C++17, which includes:
  - gcc 7.1   (released 2017-05-02)
  - clang 5.0 (released 2017-09-07)

You will need the following libraries:
  - libuuid (not needed for OSX)

You will need a Rust toolchain of the Minimum Supported Rust Version (MSRV):
  - rust 1.81.0

Basic Installation
------------------

Briefly, these shell commands will unpack, build and install Taskwarrior:

  $ tar xzf task-X.Y.Z.tar.gz                        [1]
  $ cd task-X.Y.Z                                    [2]
  $ cmake -S . -B build -DCMAKE_BUILD_TYPE=Release . [3]
  $ cmake --build build                              [4]
  $ sudo cmake --install build                       [5]
  $ cd .. ; rm -r task-X.Y.Z                         [6]

These commands are explained below:

  1. Unpacks the source tarball.  This creates the directory task-X.Y.Z,
     containing all the code.

  2. Change directory to the root of the distribution.

  3. Invokes CMake to scan for dependencies and machine-specific details, then
     generate the makefiles.  Requests an optimized build, which will run faster
     and be more compact.  This may take a minute.

  4. Builds Taskwarrior.  This may take a minute.

  5. Installs the program, documentation and other data files.

  6. Removes the temporary directory.


Build and configurations options
--------------------------------

You can customize the configuration run with cmake variables. This will modify
the installation process:

To change the installation directory you use the following configuration
variable:

  $ cmake -DCMAKE_INSTALL_PREFIX=<path-to-installation-dir> .

cmake configuration variables are applied with the -D option and consist of a
<name> and a <value>:

  $ cmake -D<name>=<value> .

Four more variables can customize the installation process. The following table
lists them and their defaults plus the CMAKE_INSTALL_PREFIX:

  CMAKE_INSTALL_PREFIX  /usr/local
  TASK_BINDIR           bin
  TASK_DOCDIR           share/doc/task
  TASK_RCDIR            share/doc/task/rc
  TASK_MAN1DIR          share/man/man1
  TASK_MAN5DIR          share/man/man5

The corresponding TASK_* variables will be combined with CMAKE_INSTALL_PREFIX to
get absolute installation directories:

  CMAKE_INSTALL_PREFIX/TASK_BINDIR   /usr/local/bin
  CMAKE_INSTALL_PREFIX/TASK_DOCDIR   /usr/local/share/doc/task
  CMAKE_INSTALL_PREFIX/TASK_RCDIR    /usr/local/share/doc/task/rc
  CMAKE_INSTALL_PREFIX/TASK_MAN1DIR  /usr/local/share/man/man1
  CMAKE_INSTALL_PREFIX/TASK_MAN5DIR  /usr/local/share/man/man5

The following variables control aspects of the build process:

  SYSTEM_CORROSION - Use system provided corrosion instead of vendored version
  ENABLE_TLS_NATIVE_ROOTS - Use the system's TLS root certificates


Uninstallation
--------------

There is no uninstall option in CMake makefiles. This is a manual process.

To uninstall Taskwarrior, remove the files listed in the install_manifest.txt
file that was generated when you built Taskwarrior.


Taskwarrior Build Notes
-----------------------

Taskwarrior has dependencies that are detected by CMake in almost all cases, but
there are situations and operating systems that mean you will need to offer a
little help.

If Taskwarrior will not build on your system, first take a look at the Operating
System notes below.  If this doesn't help, then go to the Troubleshooting
section, which includes instructions on how to contact us for help.

Offline Build Notes
-------------------

It is common for packaging systems (e.g. NixOS, FreeBSD Ports Collection, pkgsrc, etc)
to disable networking during builds.  This restriction requires all distribution files
to be prepositioned after checksum verification as a prerequisite for the build.  The
following steps have been successful in allowing Taskwarrior to be built in this
environment:

1. Extract all crates in a known location, e.g. ${WRKDIR}/cargo-crates
This includes crates needed for corrosion (search for Cargo.lock files)

2. Create .cargo-checksum.json for each crate
For example:
printf '{"package":"%s","files":{}}' $(sha256 -q ${DISTDIR}/rayon-core-1.12.1.tar.gz) \
        > ${WRKDIR}/cargo-crates/rayon-core-1.12.1/.cargo-checksum.json

3. Create a custom config.toml file
For example, ${WRKDIR}/.cargo/config.toml
[source.cargo]
directory = '${WRKDIR}/cargo-crates'
[source.crates-io]
replace-with = 'cargo'

4. After running cmake, configure cargo
For example:
cd ${WRKSRC} && ${SETENV} ${MAKE_ENV} ${CARGO_ENV} \
  /usr/local/bin/cargo update \
  --manifest-path ${WRKDIR}/.cargo/config.toml \
  --verbose

5. Set CARGO_HOME in environment
For example
CARGO_HOME=${WRKDIR}/.cargo

The build and installation steps should be the same as a standard build
at this point.

Operating System Notes
----------------------

Cygwin
  If 'make install' fails when writing to the /usr/local/share/ directory,
  this may be because your current login doesn't have permission to write
  to the Windows directory containing your Cygwin installation. Either
  login to Windows as an Administrator and try the 'make install' process
  again, or reinstall Cygwin under your normal Windows login.


Darwin, 32bit
  Taskwarrior needs to be built from source, and use this configure command:

    cmake -DCMAKE_C_FLAGS=-m32 -DCMAKE_CXX_FLAGS=-m32 -DCMAKE_EXE_LINKER_FLAGS=-m32 .

  See:
    https://taskwarrior.org/issues/817
    https://stackoverflow.com/questions/3261909/build-32bit-on-64-bit-linux-using-a-configure-script
    https://stackoverflow.com/questions/2617508/cmake-gcc-cuda-and-m32-wtf
    https://stackoverflow.com/questions/6077414/cmake-how-to-set-the-ldflags-in-cmakelists-txt


OpenBSD
  In order to build Taskwarrior 2.4.2+, you might need to install a newer GCC
  version from ports or packages.

  Afterwards, run
    cmake -DCMAKE_CXX_COMPILER=eg++ .

  and build normally.

  See: https://github.com/GothenburgBitFactory/taskwarrior/issues/1605

WASM
  Using the Emscripten compiler, you can achieve it like this:

    cmake -DCMAKE_CXX_COMPILER=emcc -DCMAKE_BUILD_TYPE=release -DENABLE_WASM=ON \
          -DCMAKE_EXE_LINKER_FLAGS="-m32 -s NO_DYNAMIC_EXECUTION=1 -s WASM=1 -s NO_EXIT_RUNTIME=1 -s INVOKE_RUN=0" \
          -DCMAKE_CXX_FLAGS_RELEASE="-O2 -m32"

  This will produce an optimized WASM with a main() that is callable multiple times.

Troubleshooting
---------------

If you've recently made changes to dependencies (by reinstalling them, for
example) be sure to rerun 'cmake .' before trying to execute 'make' again.

CMake will run and locate all the necessary pieces for the build, and create
a Makefile.  There may be errors and warnings when running CMake, or there
may be compiler errors and warnings when running 'make'.  Sometimes you will run
CMake with no reported problems, and the build will fail later.  This is
almost always because CMake is mistaken about some assumption.

If a build does not succeed, please send the contents of the 'CMakeCache.txt'
and 'CMakeFiles/CMakeOutput.log' files to support@gothenburgbitfactory.org.

If CMake runs but Taskwarrior does not build, please send the contents of the
above files as well as a transcript from the build, which is not written to a
file and must be captured from the terminal.

---
