atomi/ignore

atomi/ignore

AtomiCloud's dot ignore merger. Merges .gitignore, .dockerignore, and similar dot-ignore files from multiple templates and layers into a single resolved output.

Purpose

When multiple templates or layers contribute an ignore file (e.g., .gitignore, .dockerignore) to the same path, this resolver merges them into one file. Each template's patterns are combined into the final output.

Resolution Strategy

The resolver picks the first file from the input and returns it as the resolved output. This is a stub implementation -- the full merge strategy (pattern concatenation with deduplication) has not yet been implemented.

When fully implemented, the resolver will:

• Concatenate all ignore patterns from every contributing file
• Deduplicate identical patterns
• Produce a single merged ignore file

Configuration Schema

Key	Type	Default	Description
sectionOrder	string	alphabetical	Strategy for ordering ### <group> sections in the final output. See Strategies.

Strategies

sectionOrder accepts one of four values — the same four, with the same names and the same meanings, as atomi/md:

Value	Behavior
alphabetical	Sort by group name (A–Z)
reverse-alphabetical	Sort by group name (Z–A)
lowest-layer-first	Sort by origin layer ascending (layer 0 before layer 1)
highest-layer-first	Sort by origin layer descending (layer 1 before layer 0)

Any other value throws, naming the field and the valid set.

Two details that follow from the mechanism:

• The unnamed preamble sorts as the empty string. Under alphabetical it stays first, which is the historical behaviour; under reverse-alphabetical it lands last; under the layer strategies it sits at its own layer's position.
• A group contributed by several templates takes one origin. Under highest-layer-first that is its highest-layer contributor; under every other strategy, its lowest. Layer ties break on template name ascending.

Commutativity and Associativity

Note: The current stub implementation is not commutative -- it always returns files[0]. The full implementation must guarantee commutativity and associativity.

The completed resolver will ensure commutativity by:

• Deduplicating patterns after concatenation, so input order does not affect the result
• Sorting patterns alphabetically, producing a deterministic output regardless of which template contributed which line

Merge Examples

Example 1: Single file, no conflict

Input files (all sharing the same path .gitignore):

Origin Template	Origin Layer	Content
base	0	node_modules/\ndist/\n

Config:

{}

Resolved output:

node_modules/
dist/

Integration

Reference this resolver in a template's cyan.yaml:

resolvers:
  - ref: atomi/ignore@2
    config: {}
    files: ['.gitignore', '.dockerignore', '.ignore']