moonrepo/moon v2.6.0

2.6.0

on GitHub

Release Notes

🚀 Updates

• Action pipeline
  • Improved the performance of the action pipeline's job dispatcher by 10-15x. Dependency
    relationships are now extracted from the action graph once up front, and completed jobs unblock
    their dependents incrementally, instead of re-traversing the graph for every dispatch check.
  • Changed persistent tasks to run when they are processed in the action graph, instead of being
    batched and ran last, in parallel, once all other actions have finished. Persistent tasks now
    run alongside other tasks, and a persistent task no longer blocks the persistent tasks that
    depend on it. Non-persistent tasks are still not allowed to depend on persistent tasks, unless
    they only wait for them to start, with the new wait dependency type.
  • Interactive tasks now only block the pipeline until they have completed themselves, instead of
    until every task that was already running has completed.
  • Removed the action graph's "transitive reduction", which never removed any edges, as it started
    from the workspace sync action, which has no dependencies to walk. Edges that are implied by a
    longer path don't change the order that actions run in.
• CLI
  • Added OpenTelemetry metrics for the action pipeline, which are exported when --otel (or
    MOON_OTEL) is enabled.
    • Records moon.task.runs and moon.task.duration for every task that runs, labeled with the
      target, project, task, toolchains, status, and flakiness.
    • Records moon.action.executions and moon.action.duration for every action that runs,
      labeled with the target, project, or toolchain that it operated on.
    • Records moon.operation.executions and moon.operation.duration for every operation within
      those actions, labeled with the operation type, status, and plugin.
  • Added a new --output-style option to moon run, moon ci, moon check, and moon exec,
    which controls how output is displayed for all tasks, overriding their options.outputStyle.
    Since it is requested explicitly, it also applies to primary targets. For example,
    moon ci :test --output-style buffer-only-failure keeps passing tasks quiet and prints the full
    output of failing ones.
  • Updated the MCP server (moon mcp) to the stateless MCP 2026-07-28 protocol. Clients must
    support this protocol version, as older versions (2025-11-25 and below) and the initialize
    handshake are no longer supported.
• Cache
  • Hash manifests are now stored as blobs in the local content-addressable cache, instead of as
    individual files in .moon/cache/hashes. The local cache backend is now always enabled, as it
    backs these manifests; storing task outputs in it remains gated by the cas_outputs_cache
    experiment. Blobs that no task manifest references (like hash manifests) are now garbage
    collected once older than the cache lifetime, instead of after an hour, while blobs of evicted
    task manifests are still removed after an hour.
  • Added request retries to the HTTP remote cache, which retries a request that failed with a
    transient error (connection failure, timeout, 5xx, 408, or 429 response) with exponential
    backoff. Previously, a single failed blob download would fail the task with
    task_runner::missing_outputs (#2680).
    • Added a new remote.cache.retryCount setting, which defaults to 3, and can be set to 0 to
      disable retries. Can also be set with the MOON_REMOTE_CACHE_RETRY_COUNT environment
      variable.
    • The HTTP remote cache is now disabled when its host is unreachable while connecting, instead
      of every request failing, as each request would have exhausted its retries.
• Configuration
  • Added Pkl modules for every configuration file, which are generated to .moon/cache/schemas/pkl
    when pkl is installed. A .pkl config that amends (or extends) its module is type checked by
    Pkl itself, and editors with Pkl support provide completion and documentation for each setting.
  • Added an args setting to toolchain bins entries, which passes additional arguments to the
    install command, like feature flags (--no-default-features --features postgres). Support is
    dependent on each toolchain plugin (#2708).
• Experiments
  • Added a new experiments.explicitTaskOutputStyle setting, which applies a task's
    options.outputStyle to all targets, instead of only transitive (non-primary) ones. Can also be
    enabled with the MOON_EXPERIMENT_EXPLICIT_TASK_OUTPUT_STYLE environment variable.
• Tasks
  • Added a new type setting to task deps, which controls when a dependency runs in relation to
    the task. Supports the following values:
    • required (default) - Runs before the task, and must complete successfully.
    • cleanup - Runs after the task has ran its command, even when the task fails, or the failure
      aborts the pipeline. Useful for tearing down resources, like stopping a database. It's skipped
      when there's nothing to clean up (the task was skipped, or hydrated from the cache, without
      having started a wait dependency).
    • wait - Runs before the task, but the task only waits for it to start running, not to
      complete. Useful for long-running dependencies, like a development server, and allows
      non-persistent tasks to depend on persistent tasks.
    • Since cleanup and wait dependencies don't complete before the task runs, they don't
      contribute to the task's hash, and they always run their command, instead of being hydrated
      from the cache.
  • Changed runDepsInParallel (when disabled) to skip persistent dependencies when ordering the
    dependencies that follow them, as a persistent dependency never completes. Those dependencies
    are now ordered against the previous dependency that does complete.
  • Added a new options.expectFailure task setting, which expects the task to fail, and fails the
    pipeline if it passes instead, with an error to remove the setting. Useful for checks that are
    known to be broken, like after enabling a stricter compiler or lint rule during a migration, so
    that future regressions are caught once fixed (#2536).
    • Unlike allowFailure, other tasks can depend on the task, as an expected failure is
      successful.
    • Exit codes 126 (command not executable), 127 (command not found), and 129-192 (killed
      by a signal) don't satisfy the expectation, nor do timeouts or signals.
    • The task is never cached, and is not retried after failing as expected, or passing.
    • Cannot be combined with allowFailure or persistent.
  • Added a new options.envOverride task setting, which allows the task's env (and deps.*.env)
    to override system environment variables (those set in the shell or CI), instead of only being
    set when missing. Supports true for all variables, or a list of variable names, like
    ['NODE_ENV', 'TZ']. PATH and envFile variables are never overridden (#2679).
• Toolchains
  • Added support for the proto activate_environment plugin function to toolchains. When building
    a command (for tasks and toolchain operations), the environment of each toolchain that has been
    setup is now activated, which may set environment variables (like JAVA_HOME for Java) and
    prepend paths to PATH. Variables that are already configured, like a task's env, are not
    overridden, and the first toolchain configured for a task takes precedence (#2568).

🧰 Toolchains

• Deno, Go, Rust
  • Added bins.*.args support, which are custom arguments passed their respective install command.
    Bins with args are installed in separate commands.

🐞 Fixes

• Fixed an issue where a task dependency's env (deps.*.env) would override system environment
  variables, instead of only being set when missing, like the task's env.
• Fixed an issue where a task's resolved toolchains list was ordered by an internal hash set,
  instead of by what was configured. The toolchains configured for a task (or inherited from the
  project) now come first, followed by any toolchains they require. This also fixes the
  $taskToolchain token, which would expand to a required toolchain (like npm) instead of the
  configured one (like node), and makes the append/prepend merge strategies apply to
  toolchains as they do to other task fields. Since this list is part of a task's hash, existing
  caches will be invalidated once.
• Fixed an issue where a task's options.outputStyle was applied to primary targets (those
  explicitly requested on the command line) when running in CI, or when the task was hydrated from
  the cache. Primary targets now always display their output, as documented, unless the
  explicitTaskOutputStyle experiment is enabled.
• Fixed an issue where JSON output containing project configuration (moon project --json,
  moon query projects, MCP responses, and webhook payloads) serialized renamed settings under the
  wrong keys: typeOf instead of type (tasks), runInCi instead of runInCI (task options), and
  schema instead of $schema. The output now matches the documented JSON schemas and
  @moonrepo/types.
• Fixed an issue where environment variables removed through moon's internal environment bag (for
  example NO_COLOR when colors are forced) were not removed from the current process, and could be
  inherited back into the bag on a subsequent read.
• Fixed an issue where a task with options.retryCount would attempt to run again after the
  pipeline was aborted (because another task failed) or interrupted (like with Ctrl+C), which
  started a new process that was never terminated, and could continue running after moon exited.
• Fixed an issue where a task that had yet to run its command when the pipeline was aborted or
  interrupted (it was still generating its hash, or waiting on a mutex) would run it afterwards,
  which started a process that was never terminated.
• Fixed an issue where tasks that depend on a persistent task would still run when the persistent
  task was skipped (because one of its own dependencies failed), when failures don't abort the
  pipeline (like with moon ci).
• Fixed an issue where a task dependency would be inserted into the action graph (and ran) more than
  once, when its env was defined in a different order by the tasks that depend on it.
• Fixed an issue where a task that is ran more than once in the same pipeline (with different args
  or env, as a dependency of other tasks) would fail with a missing dependency hash error, or
  ignore its own dependencies, when running with --upstream direct. Its dependencies are now
  linked for every instance of the task, once they are in scope for one of them.
• Fixed an issue where the action graph would fail with a cycle error, when the order of
  dependencies for a task with options.runDepsInParallel disabled contradicts a dependency between
  them, and that dependency is linked after they were ordered (like when running with
  --upstream direct). Dependencies now always take precedence over the configured order.
• Fixed an issue where a persistent task would run in CI by default, when it defined outputs, or a
  type of build or test, which keeps the pipeline running. Persistent tasks no longer run in
  CI, unless options.runInCI is explicitly enabled.
• Fixed an issue where a persistent task with options.runInCI enabled would be ran in CI on its
  own (by moon ci when it was affected, or when a task that it depends on was ran), which keeps
  the pipeline running. In CI, persistent tasks are now only ran when another task depends on them,
  or when they're explicitly passed as a target.
• Fixed an issue where moon check would run persistent tasks (those that define outputs, or a
  type of build or test), so the command would never complete. Persistent tasks are now only
  ran by moon check when another task depends on them.
• Fixed an issue where moon check would prompt for a list of tasks to run, or fail with an
  identifier error in non-TTY environments, when the projects being checked have no build or test
  tasks. It now reports that there's nothing to check.

⚙️ Internal

• Updated proto to v0.62.2 from 0.60.2.
• Updated Rust to v1.99.0.
• Updated dependencies.

Install moon_cli 2.6.0

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://github.com/moonrepo/moon/releases/download/v2.6.0/moon_cli-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://github.com/moonrepo/moon/releases/download/v2.6.0/moon_cli-installer.ps1 | iex"

Download moon_cli 2.6.0