CLI: deduplicate overlapping file globs in test-examples

[jcouball]

Summary

Deduplicate file paths returned by parse_files so overlapping globs/directories do not execute the same example file multiple times.

Motivation

parse_files currently flattens matched paths without uniqueness filtering. Passing overlapping patterns (for example app plus app/**/*.rb) yields duplicate entries, which causes duplicate YARD parsing and duplicate generated tests.

Concrete example

parse_files(['app', 'app/**/*.rb'])
# => ["app/a.rb", "app/a.rb"]

This can inflate run counts and make failures appear multiple times even though source files are unique.

Current behaviour

files = globs.map do |glob|
  glob = "#{glob}/**/*.rb" if File.directory?(glob)
  Dir[glob]
end

files.flatten

Proposed solution

Return a de-duplicated list while preserving stable order (first appearance wins), e.g.:

files.flatten.uniq

Optionally normalize with File.expand_path before dedupe if mixed relative/absolute globs are expected.

Scope

In scope

• Deduplicate output from parse_files
• Keep current glob expansion semantics and defaults (app, lib)
• Add tests for overlapping input patterns

Out of scope

• Changing how defaults are selected
• Recursive file type expansion beyond *.rb

Implementation notes

1. Keep output deterministic for CI and snapshot-friendly tests.
2. Preserve behavior for non-overlapping glob input.
3. Ensure no regression in feature scenarios that pass explicit file globs.

Acceptance criteria

• parse_files(['app', 'app/**/*.rb']) returns each matched file once
• Run counts do not increase due to duplicate file paths
• Existing cucumber scenarios continue to pass

Related

• lib/yard/cli/test_examples.rb — parse_files
• lib/yard/cli/test_examples.rb — run