Module: Moult::Churn

Defined in:
lib/moult/churn.rb

Overview

Per-file change frequency from git history. "Change" means a commit that touched the file; the count is the number of such commits within the window.

Decisions (v0.1):

* Window: the last 12 months by default ({DEFAULT_SINCE}), configurable via
+since+ (anything `git log --since` accepts, e.g. "2025-01-01"). All of
history over-weights long-lived files, so we bound it.
* Renames are NOT followed. `git log --follow` only works for a single
pathspec, so whole-repo rename tracking is out of scope; a renamed file
starts a fresh count under its new path.
* Outside a git repository, churn is empty (every file scores 0).

Paths are reported relative to the repository root, as git emits them.

Constant Summary collapse

DEFAULT_SINCE = 
"12 months ago"

Class Method Summary collapse

Class Method Details

.collect(root:, since: DEFAULT_SINCE) ⇒ Hash{String=>Integer}

Returns path => commit count (default 0).

Parameters:

  • root (String) —

    directory to run git in

  • since (String) (defaults to: DEFAULT_SINCE) —

    git --since boundary

Returns:

  • (Hash{String=>Integer}) —

    path => commit count (default 0)



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# File 'lib/moult/churn.rb', line 27

def collect(root:, since: DEFAULT_SINCE)
  output = Git.log_name_only(root, since: since)
  return empty_counts unless output

  parse(output)
end

.empty_counts ⇒ Object 



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# File 'lib/moult/churn.rb', line 48

def empty_counts
  Hash.new(0)
end

.parse(output) ⇒ Hash{String=>Integer}

Pure parser over git log --name-only --pretty=format: output. Counts how many lines (commits) mention each path.

Parameters:

  • output (String)

Returns:

  • (Hash{String=>Integer}) 


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# File 'lib/moult/churn.rb', line 38

def parse(output)
  counts = empty_counts
  output.each_line(chomp: true) do |line|
    next if line.empty?

    counts[line] += 1
  end
  counts
end