# Loading

## Overview

See the Firefox loading documentation. In addition to those loaders, in
`comm_taskgraph.loader` there are loaders for Thunderbird.

## comm_taskgraph.loader

### reference

Loads selected tasks from a different taskgraph hierarchy.

The `reference` loader is used to import kinds from the Firefox Taskcluster
base path.

`packages`, and `fetch` use this loader.

When using the `reference` loader, optionally include `reference-tasks`
in kind.yml to select which tasks to import. `reference-tasks` uses gitignore
style pattern matching via `pathspec`.

**Include patterns**

```yaml
reference-tasks:
  - linux64-aarch64-compiler-rt-20
  - linux64-cargo-vet
  - linux64-cbindgen
  - linux64-cctools-port
  - linux64-clang-21-profile
  - linux64-clang-21-raw
```

**or use wildcards**

```yaml
reference-tasks:
  - linux64-*
  - win64-*
```

**and exclude patterns**

```yaml
reference-tasks:
  - "*"
  - "!ub22-arm64*"
```

**Note:**

When using exclude patterns only, first you must include everything with an "*"
entry.
The "*" line and the exclusion lines must be quoted due to ensure YAML interprets
those lines as strings.

### merge

Loads tasks for a kind from two Taskcluster base paths. The results are "merged"
together into a single kind, allowing for using the Firefox defined tasks as
a base and adding additional tasks.

First tasks are imported from Firefox's Taskcluster base path using the reference
loader. Then tasks are read from the kind directory using `tasks-from`.

`docker-image` and `toolchain` use this loader.