Mason is Chapel’s package manager

Installation Instructions

In $CHPL_HOME run the following:

make mason

It builds the mason binary so that the command line interface can be used. This installs mason in the same place as the chapel compiler (chpl) so that mason can be used anywhere in the user’s file system.

To remove mason, change directory to $CHPL_HOME/tools/mason and run:

make clean

Basic Usage

Starting a New Package

To initialize a new mason package, run mason new. The same can also be done using mason init as follows:

mkdir newPackage
cd newPackage
mason init

This starts an interactive session which walks a user through the process of creating a project using Mason. This is highly recommended for new users.

A more advanced user may use the mason new [ options ] <project name> command, for example:

mason new MyPackage

This creates a git repository by default, unless --no-vcs is included.

Mason packages can also be initialized using the mason init [options] [directory path]. To avoid the interactive session while initializing the project, run mason init -d | --default.

For example, for an existing directory named MyPackage,

mason init MyPackage

# OR

cd MyPackage
mason init -d

The package will have the following hierarchy:

 ├── Mason.toml
 ├── example/
 ├── src/
 │   └── MyPackage.chpl
 └── test/

The first file listed is the Mason.toml. This is the manifest file for the package. All dependencies for the package are listed in this file as well as additional metadata about the package.

The src/ folder is where the source code of the package should reside. As you might expect, the test/ folder and the example folder hold tests and examples for your package, respectively. We will get to the additional functionality that comes with these folders later.

Mason enforces that the main file be named after the package to enforce namespacing. MyPackage.chpl will be the first file listed in src/.

You can create a package in a directory that differs from the mason package name with the mason {new,init} –name flag. This may be useful when creating a package in a directory that is an illegal Mason package name, such as names with dashes. For example,

mason new illegal-module-name --name LegalModuleName

# OR

mkdir illegal-module-name
mason init illegal-module-name --name LegalModuleName

Building and Running

When invoked, mason build [ options ] will do the following:

  • Run update to make sure any manual manifest edits are reflected in the dependency code.

  • Build MyPackage.chpl in the src/ directory.

  • All packages are compiled into binaries and placed into target/

  • All options not recognized by mason will be forwarded to the chapel compiler(chpl)

mason run [ options ] will, in turn:

  • Run the executable built above out of target/, if it exists.

  • All options not recognized by mason will be forwarded to the executable.

For example, after mason run --build [ options ], the package directory appears as follows:

 ├── Mason.lock
 ├── Mason.toml
 ├── example/
 ├── src/
 │   └── myPackage.chpl
 ├── target/
 │   ├── debug/
 │   │   └── myPackage
 │   ├── example/
 │   └── test/
 └── test/

As you can see, new files have been added to the package, the first of which is the Mason.lock. You can think of this file as a snapshot of a single run of the program. This file “locks” in the settings in which the program ran upon invocation of mason run. This file can be generated manually with the mason update command. mason update will read the Mason.toml, resolve dependencies, and generate the Mason.lock based on it’s contents.

The target/ directory is where Mason stores all the binaries related to your package. These could be binaries for the main source code as well as examples and tests. There are two types of targets for building. The default location of a package binary is target/debug/, as shown in the example above. However, if a final version of an application or library is being produced, the --release flag can be thrown as follows:

mason run --build --release --force

The --release option adds the --fast argument to the compilation step.

The argument --force is included as Mason will only build the package if the package has been modified. Throwing the --release flag will result in the following package structure:

 ├── Mason.lock
 ├── Mason.toml
 ├── example/
 ├── src/
 │   └── myPackage.chpl
 ├── target/
 │   ├── debug/
 │   │   └── myPackage
 │   ├── example/
 │   ├── release/
 │   │   └── myPackage
 │   └── test/
 └── test/

As you can see there are now two binaries of MyPackage, one under debug/ and one under release. To remove the target/ directory along with all of the binaries for your package, use the mason clean command.

Building Larger Packages

For packages that span multiple files, the main module is designated by the module that shares the name with the package directory and the name field in the Mason.toml.

For packages that span multiple sub-directories within src, sub-directories must be passed to Mason with the -M  <src/subdirectory> flag which is forwarded to the chapel compiler. For example, lets say MyPackage’s structure is as follows:

 ├── Mason.lock
 ├── Mason.toml
 ├── example/
 ├── src/
 │   ├── myPackage.chpl
 │   └── util/
 │       └── myPackageUtils.chpl
 ├── target/
 │   ├── debug/
 │   │   └── myPackage
 │   ├── example/
 │   └── test/
 └── test/

If MyPackage needs multiple files in different directories like the example above, then call mason build with the -M flag followed by the local dependencies. A full command of this example would be:

mason build -M src/util/MyPackageUtils.chpl

Runtime/Compilation Arguments

For an example of forwarding arguments in a call to mason run, a chapel program built in mason might have a config const number that corresponds to a value used in MyPackage.chpl. To try out different values at runtime, pass the values for number to mason run as follows:

mason run -- --number=100
mason run -- --number=1000


Previous releases allowed flags meant for the compiler or chapel program to be mixed with those meant for mason build or mason run, respectively. As of Chapel 1.25 and mason 0.2.0, flags not intended for mason must follow a double dash -- regardless of if they conflict or not.

Testing your Package

Mason provides the functionality to test packages through the mason test subcommand. There are two styles of writing mason tests:

  1. Tests that utilize the UnitTest` module to determine pass/fail status

  2. Tests that rely on the exit code to determine pass/fail status

Here is an example of a UnitTest-based tests:

use UnitTest;

config const testParam: bool = true;

proc myTest(test: borrowed Test) throws{


Mason testing that uses UnitTest will treat each individual function as a test, and the test will be considered successful if no assertions failed and no halts were reached within the function body.

See the UnitTest documentation to learn more about writing unit tests in Chapel.

Here is an example of an exit-code-based tests:

config const testParam: bool = true;

if testParam {
  writeln("Test Passed!");
else {

Mason testing that relies on exit code tests each file as a test, and the test will be considered successful if the program compiled and exited with an exit code of 0.

These tests should be configured such that a failure produces an exit code other than 0. Returning a non-zero exit code can be accomplished by calling exit() or throwing an uncaught error.

Both exit-code and UnitTest style tests can be used within a single mason package.

After adding our test, the package structure will be as follows:

 ├── Mason.lock
 ├── Mason.toml
 ├── example/
 ├── src/
 │   └── myPackage.chpl
 ├── target/
 │   ├── debug/
 │   │   └── myPackage/
 │   ├── example/
 │   ├── release/
 │   │   └── myPackage
 │   └── test/
 └── test/
      └── myPackageTest.chpl

Use mason test to run the test(s). If tests are not explicitly specified in Mason.toml, Mason will gather all the tests found in test/, compile them with the dependencies listed in your Mason.toml and run them producing the following output:

--- Results ---
Test: myPackageTest Passed

--- Summary:  1 tests run ---
-----> 1 Passed
-----> 0 Failed

Specific tests can be run by listing their names or substrings of their names as command line arguments:

# Run these specific tests:
mason test test/test1.chpl test/test2.chpl
# Run any test file with 'test1' or 'test2' in the name
mason test test1 test2
# Run any test file with the '1' in the name
mason test 1

Specifying tests to run in the command line ignores the list of tests in Mason.toml, and searches all files in test/.

Additional output can be displayed by throwing the --show flag.


mason test can also be used outside of a mason package as a UnitTest test runner. See UnitTest for more information.

Tests can be listed in the Mason.toml as a TOML array of strings for the tests field:

chplVersion = "1.18.0"
license = "None"
name = "myPackage"
tests = ["test1.chpl",
version = "0.1.0"

An user may also set the CHPL_COMM value for running the tests, e.g. none, gasnet, ugni using mason test --setComm.

Creating and Running Examples

Mason supports examples as a way to demonstrate typical usage of a package. The following example adds an example to MyPackage and runs it. The example below prints a message a number of times based on the config const count:

config const count: int = 10;

for i in 1..count {
  writeln("This is an example!!");

To build the example without running it, use the command mason build --example. This command will build ALL examples found either in the example/ directory or listed in the Mason.toml


If examples or tests are listed in the Mason.toml, Mason will not search for any examples or tests not listed.

To view what examples are available, enter mason run --example without any other arguments. This will produce the names of all examples that are currently available to Mason:

--- available examples ---
--- myPackageExample.chpl

To run the example, use the command mason run --example myPackageExample.chpl.

After the program is run via the command above, the package structure will look as follows:

 ├── Mason.lock
 ├── Mason.toml
 ├── example/
 │   └── myPackageExample.chpl
 ├── src/
 │   └── myPackage.chpl
 ├── target/
 │   ├── debug/
 │   │   └── myPackage
 │   ├── example/
 │   │   └── myPackageExample
 │   ├── release/
 │   │   └── myPackage
 │   └── test/
 └── test/
      └── myPackageTest.chpl

Examples can either be specified in the Mason.toml, or found automatically by Mason. However, to include compile time or runtime arguments for examples, users must explicitly declare them in their Mason.toml as follows:

chplVersion = "1.18.0"
license = "None"
name = "myPackage"
version = "0.1.0"


examples = ["myPackageExample.chpl"]

compopts = "--savec tmp"
execopts = "--count=20"

Documenting a Package

Creating a website for package documentation is a breeze with Mason. Mason uses chpldoc which turns any .chpl file into Sphinx documentation. To document a package, run the command mason doc while inside of a package. The documentation will be automatically generated as long as chpldoc has been set up. For instructions on how to set up chpldoc, view its documentation. Documentation will be built into the doc/ folder that will be created upon the first call of mason doc.

Using Chapel Dependencies

There are multiple types of dependencies in Mason. Chapel or “Mason” dependencies are other Mason packages that you want to use in your Mason package.

To search through all the current available Mason packages, use mason search.

Chapel Dependencies are listed under the [dependencies] table in the Mason.toml file of the package as follows:

chplVersion = "1.18.0"
license = "None"
name = "myPackage"
version = "0.1.0"

MatrixMarket = 0.1.0

To add a Chapel dependency without editing the Mason.toml manually, use the mason add command as follows:

mason add MatrixMarket@0.1.0

Using Non-Chapel Dependencies

Mason allows for specification of external, non-Chapel dependencies through two mediums, Spack and pkg-config. The following two sections document how to use mason external and mason system to interface with Spack and pkg-config packages respectively.

Using System Dependencies

System dependencies are packages that are found on your system through pkg-config. To use this functionality of Mason, users must have pkg-config installed.

Mason interfaces with pkg-config through the mason system command.

mason system search will print all the current packages installed and available for use in a Mason package. To examine the .pc file of a particular package, use mason system pc <package> where <package> is replaced with the particular package you are looking for. Here is an example of a workflow for creating a Mason package with openssl which has already been installed.

First, search to see that it is installed with mason system search openSSl which outputs:

$ mason system search openssl
openssl               OpenSSL - Secure Sockets Layer and cryptography libraries and tools

To find out more about the package, since it is in fact installed on my system, use the mason system pc command as follows

$ mason system pc openssl

------- openSSL.pc -------


Name: OpenSSL
Description: Secure Sockets Layer and cryptography libraries and tools
Version: 0.9.8zh
Libs: -L${libdir} -lssl -lcrypto -lz
Cflags: -I${includedir}


Use the mason add --system command to add the dependency to the Mason.toml of the package.

$ mason add --system openSSL@0.9.8zh
Adding system dependency openSSL version 0.9.8zh

The Mason.toml now looks like:

chplVersion = "1.18.0"
license = "None"
name = "myPackage"
version = "0.1.0"

openSSL = "0.9.8zh"

Now, upon calling mason build or mason run --build, Mason will go get openssl and include it in the package so that it can be used as a dependency.

Using Spack Dependencies

Mason users can interface with Spack, a package manager geared towards high performance computing. Through this integration, Mason user’s now have access to a large ecosystem of packages. Non-destructive installs, custom version and configurations, and simple package installation and uninstallation are a few of the features Mason gains through this integration.

Mason users can access Spack through the mason external command. Spack provides Mason users with the ability to install and use any package in the Spack registry. This interface is analogous to the previous example except when a package is missing, user’s can download that package through the Spack integration. The following is a workflow of finding, installing, and adding a Spack dependency to a Mason Package.

Setting up Spack backend

First, the Spack backend must be installed. Users can have mason install Spack or point mason to an existing spack installation.

This command will install Spack into $MASON_HOME/spack and set it up so that it can be used by Mason. It should be noted that this command pulls from the master branch of spack for setting up the spack registry at $MASON_HOME/spack-registry:

mason external --setup

Alternatively, users can set $SPACK_ROOT to their own spack installation:

export SPACK_ROOT=/path/to/spack

Searching Spack packages

Let’s use openSSL as an example since we used it in the system example. mason external search openSSL will search for the package and produce the following output:

$ mason external search openSSL
==> 2 packages.
openssl  r-openssl

Obviously there are two types of the package listed, so we need to figure out which one to use. To find out more about a package, use mason external info <package> as follows:

$ mason external info openssl
Package:   openssl

OpenSSL is an open source package that provides a robust, commercial-
grade, and full-featured toolkit for the Transport Layer Security (TLS)
and Secure Sockets Layer (SSL) protocols. It is also a general-purpose
cryptography library.



Preferred version:

Safe versions:


Installation Phases:

Build Dependencies:

Link Dependencies:

Run Dependencies:

Virtual Packages:

Installing Spack packages

The correct package has been found, but not yet installed. Let’s fix that. We know that we want the preferred version which is 1.0.2k. The command to install openssl version 1.0.2k would be:

mason external install openssl

Since the version was left out, version 1.0.2k is used because Mason will always take the preferred version. This is a case where Spack’s spec expression syntax can be used to specify exactly which package is desired. For example, other ways to install openSSL would be:

mason external install openssl@1.0.2k

which simply specifies the exact version that we want. If we wanted to specify which compiler the package was built with:

mason external install openssl@1.0.2k%gcc

Mason will infer which compiler, in the case that the compiler is left out of the spec, by looking at the environment variable CHPL_TARGET_COMPILER. For more information on how to use spec expressions, use the command mason external --spec which would output the following:

 spec expression syntax:

package [constraints] [^dependency [constraints] ...]

package                           any package from 'spack list'

    @version                      single version
    @min:max                      version range (inclusive)
    @min:                         version <min> or higher
    @:max                         up to version <max> (inclusive)

    %compiler                     build with <compiler>
    %compiler@version             build with specific compiler version
    %compiler@min:max             specific version range (see above)

    +variant                      enable <variant>
    -variant or ~variant          disable <variant>
    variant=value                 set non-boolean <variant> to <value>
    variant=value1,value2,value3  set multi-value <variant> values

  architecture variants:
    target=target                 specific <target> processor
    os=operating_system           specific <operating_system>
    platform=platform             linux, darwin, cray, bgq, etc.
    arch=platform-os-target       shortcut for all three above

    os=backend or os=be           build for compute node (backend)
    os=frontend or os=fe          build for login node (frontend)

    ^dependency [constraints]     specify constraints on dependencies

    hdf5                          any hdf5 configuration
    hdf5 @1.10.1                  hdf5 version 1.10.1
    hdf5 @1.8:                    hdf5 1.8 or higher
    hdf5 @1.8: %gcc               hdf5 1.8 or higher built with gcc
    hdf5 +mpi                     hdf5 with mpi enabled
    hdf5 ~mpi                     hdf5 with mpi disabled
    hdf5 +mpi ^mpich              hdf5 with mpi, using mpich
    hdf5 +mpi ^openmpi@1.7        hdf5 with mpi, using openmpi 1.7
    boxlib dim=2                  boxlib built for 2 dimensions
    libdwarf %intel ^libelf%gcc
        libdwarf, built with intel compiler, linked to libelf built with gcc
    mvapich2 %pgi fabrics=psm,mrail,sock
        mvapich2, built with pgi compiler, with support for multiple fabrics

Resuming the example, the result of the install given openssl as the sole argument would output the following:

$ mason external install openssl
==> Installing zlib
==> Fetching
==> Staging archive: /$HOME/.mason/spack/var/spack/stage/zlib-1.2.11-cpdvq4e7otjepbwdtxmgk5bzszze27fj/zlib-1.2.11.tar.gz
==> Created stage in /$HOME/.mason/spack/var/spack/stage/zlib-1.2.11-cpdvq4e7otjepbwdtxmgk5bzszze27fj
==> No patches needed for zlib
==> Building zlib [Package]
==> Executing phase: 'install'
==> Successfully installed zlib
Fetch: 4.84s.  Build: 4.24s.  Total: 9.08s.

==> Installing openssl
==> Fetching
==> Staging archive: /$HOME/.mason/spack/var/spack/stage/openssl-1.0.2k-fwnsee6qcvbbgvmgp3f5hio6dwg6nh2d/openssl-1.0.2k.tar.gz
==> Created stage in /$HOME/.mason/spack/var/spack/stage/openssl-1.0.2k-fwnsee6qcvbbgvmgp3f5hio6dwg6nh2d
==> No patches needed for openssl
==> Building openssl [Package]
==> Executing phase: 'install'
==> Successfully installed openssl
Fetch: 3.37s.  Build: 3m 11.76s.  Total: 3m 15.13s.
######################################################################## 100.0%
######################################################################## 100.0%

As shown, Mason not only goes and gets the package specified, but also all of the dependencies of the package specified. Packages are installed into unique directories such that it is impossible for package namespaces to collide. Each dependency is downloaded distinctly for a package so no previous installs will be broken by installing new packages. This way, multiple versions and builds of a package can be installed on a system and used without breaking anything.

Specifying Spack packages in the manifest file

Now that the correct package is installed, add it to the Mason.toml as follows:

$ mason add --external openssl@1.0.2k
Adding external dependency with spec openssl@1.0.2k

The Mason.toml now looks like:

chplVersion = "1.18.0"
license = "None"
name = "myPackage"
version = "0.1.0"

openSSL = "1.0.2k"

To ensure the package is installed on the system, run mason external find which will list all of the current Spack packages installed on system. For example:

==> 2 installed packages.
-- darwin-sierra-x86_64 / clang@9.0.0-apple ---------------------
openssl@1.0.2k  zlib@1.2.11

Now, everything necessary to use openssl in a Mason package has been done. Upon building, Mason will retrieve the necessary files and file locations for building myPackage with openssl.


The default mason registry is a GitHub repository containing a list of versioned manifest files.


A registry will be downloaded to $MASON_HOME/<name> by mason update for each registry named in $MASON_REGISTRY if a registry at that location does not already exist.

The registry consists of a hierarchy like the following:


Each versioned manifest file is identical to the manifest file in the top-level directory of the package repository, with the exception of a file path or URL pointing to the repository and revision in which the version is located.

Continuing the example from before, the ‘registry’ 0.1.0.toml would include the additional source field:

authors = ["Sam Partee <>"]
chplVersion = "1.16.0"
license = "None"
name = "MyPackage"
source = ""
version = "0.1.0"

curl = '1.0.0'

Search the registry with mason search <query>, which will list all packages (and their latest version) that contain <query> in their names (case-insensitive). If no query is provided, all packages in the registry will be listed.

Searching with the --show flag will output the toml file of a package if the search returns a single package. If the package has multiple versions it will return the most recent.


Packages will be listed regardless of their chplVersion compatibility.

Submit a Package

The mason registry will hold the manifest files for packages submitted by developers. To contribute a package to the mason-registry a chapel developer will need to host their package and submit a pull request to the mason-registry with the toml file pointing to their package. For a more detailed description follow the steps below. Publishing can be done with mason publish or manually.

mason publish Steps:
  1. Write a library or binary package in chapel using mason

  2. Host the package in a git repository. (e.g. GitHub)

  3. Fork the mason-registry on GitHub

  4. Ensure your package has a remote origin.

  5. Run mason publish in your package

  6. Go to the link provided to open a pull request to the mason registry.

  7. Wait for mason-registry gatekeepers to approve PR.

Manual Steps:
  1. Write a library or binary package in chapel using mason

  2. Host that package in a git repository. (e.g. GitHub)

  3. Create a tag of your package that corresponds to the version number prefixed with a ‘v’. (e.g. v0.1.0)

  4. Fork the mason-registry on GitHub

  5. Create a branch of the mason-registry and add your package’s Mason.toml under Bricks/<package_name>/<version>.toml

  6. Add a source field to your <version>.toml pointing to your package’s repository.

  7. Open a PR in the mason-registry for your newly created branch containing just your <version>.toml.

  8. Wait for mason-registry gatekeepers to approve the PR.

Once your package is uploaded, maintain the integrity of your package, and please notify the chapel team if your package should be taken down.

If you have a personal remote registry, mason publish <path-to-registry> also accepts a remote path to a git repository. This will create a branch to your registry that adds your package, and you can approve the PR to merge your new package into your registry. Must ensure your package has a remote origin in order to publish remotely.

Publishing to a personal remote registry

cd PackageA
mason publish <remote-path-to-registry>

To assess the ability of your package to be published to the mason-registry or a personal registry, run mason publish --dry-run <path-to-registry> for a series of quick checks or mason publish --check <path-to-registry for a more in depth check that will build your packages and run the full test suite.

Local Registries

It is sometimes desirable to use a local registry, for example with libraries you don’t intend to distribute. The following steps create a local registry starting with Bricks for PackageA which was created with mason new PackageA. Once you have successfully created a local registry, mason publish <path-to-local-registry> can be used to publish automatically.

First create, commit, and tag the packages that will be in the registry:

Create a local registry:

# Create the local registry
mkdir /path/to/local/registry
cd /path/to/local/registry
# Create /Bricks/DummyPackage/0.1.0.toml

# Initialize and check everything in to the git repository
git init
git add /Bricks/DummyPackage/0.1.0.toml
git commit -m 'First Commit'

Alternatively, you may automatically create a local registry by running mason publish --create-registry path/to/local/registry. Now MASON_REGISTRY can be set to point at both the local registry and the default registry.

export MASON_REGISTRY="local-registry|/path/to/local/registry,mason-registry|"

Adding a local package to the local registry

mason new PackageA
cd PackageA
git add .
git commit -m "First Commit"
mason publish <path-to-local-registry>

The MyPackage package is now free to include PackageA as dependency by adding the it as a dependency with mason add package@version

cd MyPackage
mason add PackageA@0.1.0

The Manifest File

The Mason.toml manifest file is written in TOML(for more information see TOML section below). Each time a new package is created in Mason a standard TOML file is included in the top-level directory of the package.

For example, Mason.toml:

authors = ["Sam Partee <>"]
chplVersion = "1.16.0"
license = "None"
name = "MyPackage"
version = "0.1.0"

curl = '1.0.0'

The chplVersion field indicates Chapel releases compatible with this package. There are a number of accepted formats:

"1.16.0"         # 1.16.0 or later
"1.16"           # 1.16.0 or later
"1.16.0..1.19.0" # 1.16 through 1.19, inclusive

By default, chplVersion is set to represent the current Chapel release or later. For example, if you are using the 1.16 release, chplVersion will be 1.16.0.

The license field indicates the software license under which the package is distributed. Any of the licenses available at the SPDX License List can be used for Mason packages. The license field defaults to None.

Environment Variables

Mason can be configured by setting the following environment variables:

  • MASON_HOME : Path to a directory where mason will store cached registry and package data. Defaults to $HOME/.mason.

  • MASON_REGISTRY : A comma separated list of name|location pairs, where name is a local name for the registry at location. Defaults to mason-registry| If the name| part of a pair is omitted it is inferred to be the word following the final slash in location with any .git suffix removed.

  • MASON_OFFLINE : A boolean value that prevents mason from making calls that require internet access when set to true. Defaults to false. Mason command that support a --[no-]update flag can override the MASON_OFFLINE setting when --update is explicitly passed.

The mason env command will print the inferred or set values of these environment variables. If a variable was set by the user, an asterisk will be printed at the end of the line. For example, if $MASON_HOME was set:

> mason env
MASON_HOME: /path/to/something *
MASON_REGISTRY: mason-registry|


If MASON_REGISTRY changes after invoking a mason command that updates the local copy of the registry (e.g. mason update), the local copies of the registry and dependency sources will be removed.


TOML is the configuration language chosen by the chapel team for configuring programs written in chapel. A TOML file contains the necessary information to build a chapel program using mason. TOML Spec.


All packages will exist in a single common namespace with a first-come, first-served policy. It is easier to go to separate namespaces than to roll them back, so this position affords flexibility.

Semantic Versioning

To assist version resolution, the mason registry will enforce the following conventions:

The format for all versions will be a.b.c.

Major versions are denoted by a. Minor versions are denoted by b. Bug fixes are denoted by c.

  • If the major version is 0, no further conventions will be enforced.

  • The major version must be advanced if and only if the update causes breaking API changes, such as updated data structures or removed methods and procedures. The minor and bug fix versions will be zeroed out. (ex. 1.13.1 -> 2.0.0)

  • The minor version must be advanced if and only if the update adds functionality to the API while maintaining backward compatibility with the current major version. The bug fix version will be zeroed out. (ex. 1.13.1 -> 1.14.0)

  • The bug fix must be advanced for any update correcting functionality within a minor revision. (ex. 1.13.1 -> 1.13.2)

Incompatible Version Resolution Strategy

The current resolution strategy for Mason 0.1.0 is the IVRS as described below:
  1. If multiple bug fixes of a package are present in the package, mason will use the latest bug fix. (ex. 1.1.0, 1.1.1 –> 1.1.1)

  2. If multiple minor versions of a package are present in the package, mason will use the latest minor version within the common major version. (ex. 1.4.3, 1.7.0 –> 1.7)

  3. If multiple major versions are present, mason will print an error. (ex. 1.13.0, 2.1.0 –> incompatible)

The Lock File

The lock file Mason.lock is generated after running a mason update command. The user should never manually edit the lock file as it is intended to “lock” in the settings of a certain package build iteration. Mason.lock is added by default to the .gitignore when a new package is created. If your intention is to create a binary application package that does not need to be re-compiled by mason then take the Mason.lock out of your .gitignore. An example of a lock file is written below as if generated from the earlier example of a Mason.toml:

authors = ["Sam Partee <>"]
chplVersion = "1.16.0..1.16.0"
dependencies = ['curl 1.0.0']
license = "None"
name = "MyPackage"
source = ""
version = "0.1.0"

chplVersion = "1.16.0..1.16.0"
license = "None"
name = 'curl'
source = ''
version = '1.0.0'

Dependency Code

The source code for every package will be downloaded to $MASON_HOME/src.