Composing module templates¶

[[compose]] renders sibling template repositories alongside a parent. It is different from [extends]: a child provides its own files and questions, rather than overriding the parent.

[questions.modules]
type = "list"
default = []
item_pattern = "^[a-z0-9]+(-[a-z0-9]+)*$"

[questions.module_template]
type = "string"
default = "https://github.com/org/module-template"

[[compose]]
source = "{{ module_template }}"
ref = "main"
from = "modules"

An empty answer produces no modules and never fetches the child. modules = ["jira", "confluence"] renders the child repository twice, with separate module_name answers and module_path answers modules/jira and modules/confluence. The child must declare those two string questions. If it also declares version or memcastle, an answer of the same name in the parent is forwarded. All other child questions use their own defaults and do not pollute the parent's recorded answer namespace.

The source may be a local Git repository or a URL. An expression can choose it from a parent question, which lets template tests use a local sibling repository while normal projects use a published template URL. The ref may be a branch, tag or commit. Each child source requires its own network trust decision; trusting the parent does not trust the children. Repeated module IDs, unsafe IDs, missing answers, nested composition and output path collisions are errors before the rendered tree or the destination directory is written.

Iterate the same list in a parent file:

{% raw %}{% for id in modules %}
[[modules]]
id = "{{ id }}"
{% endfor %}{% endraw %}

The parent manifest names each child ref; .config/git.tpl.toml records its resolved commit on init and update. The rendered ref also records child commits so historical backport renders the same bytes after a branch moves. Project-free render reports those commits without creating a project config. To add a module later, edit the modules answer in .config/git.tpl.toml, run git tpl update --defaults, review git tpl diff, and run git tpl merge. When a child branch advances without changing rendered files, update still records its commit and appends a provenance-only rendered-ref commit; removing all modules drops the child's recorded commit without fetching it. update still only moves refs/tpl/*; Git performs the merge into the worktree.