diff

diff <files…> --base <gitref> compares each .feature file’s working-tree text against its text at --base and classifies every scenario as added, modified, removed, or unchanged. It carries an addOnly aggregate — true when the change introduces only new scenarios and touches no existing one. This is the primitive an additive-only detector needs: addOnly: true means a purely additive change; any modified/removed means an existing scenario was touched.

gherkin-cli diff features/login.feature --base HEAD~1

Flags

Flag	Description
--base <ref>	Base git ref to compare against (required).
--full	Include unchanged scenarios in full detail.
--format <fmt>	Output format: toon (default) or json.

Behavior

• Scenario identity is the scenario name within its feature — a rename reads as add + remove.
• modified means same name, but steps, tags, or examples differ.
• Base text is read via git (git show <ref>:<path>); a git/ref failure fails loud (EGIT, exit 1).
• A brand-new file (absent at base) is entirely additive: every scenario is added, and addOnly is true.
• Aggregate summary {added, modified, removed, unchanged, files, addOnly}; each file also carries its own addOnly.

See also

• parse — project a suite into a compact digest.
• validate — check well-formedness with a gating exit code.
• diff — the same classification as an imported function.
• AXI output contract — the shared conventions behind this output.