Apply suggestions from code review

Co-authored-by: Rylan Polster <[email protected]>

Author: MikeMcQuaid

Library/Homebrew/formula_auditor.rb

@@ -903,7 +903,7 @@ def audit_revision
         problem "`revision` should only increment by 1"
       end
 
-      revision_increment = if (previous_revision = previous_committed[:revision])
+      revision_increment = if (previous_revision = newest_committed[:revision])
         current_revision - previous_revision
       else
         current_revision
@@ -919,7 +919,7 @@ def audit_revision
       missing_compatibility_bumps = changed_dependency_paths.filter_map do |path|
         changed_formula = Formulary.factory(path)
         # Each changed dependency must raise its compatibility_version by exactly one.
-        previous_committed_dependency, = committed_version_info(formula: changed_formula)
+        _, newest_committed_dependency = committed_version_info(formula: changed_formula)
         previous_compatibility_version = previous_committed_dependency[:compatibility_version] || 0
         current_compatibility_version = changed_formula.compatibility_version || 0
         next if current_compatibility_version == previous_compatibility_version + 1
@@ -939,7 +939,7 @@ def audit_compatibility_version
       return if tap.nil?
       return unless tap.git?
 
-      previous_committed, = committed_version_info
+      _, newest_committed = committed_version_info
       return if previous_committed.empty?
 
       previous_compatibility_version = previous_committed[:compatibility_version] || 0
@@ -965,7 +965,7 @@ def audit_compatibility_version
         # Only formulae that depend (recursively) on the audited formula can justify the bump.
         next unless dependencies.include?(formula.name)
 
-        previous_committed_dependent, = committed_version_info(formula: changed_formula)
+        _, newest_committed_dependent = committed_version_info(formula: changed_formula)
         previous_revision = previous_committed_dependent[:revision] || 0
         current_revision = changed_formula.revision
         next if current_revision != previous_revision + 1
@@ -1168,11 +1168,9 @@ def changed_formulae_paths(tap, only_names: nil)
         absolute_path = tap.formula_dir/relative_path
         absolute_path.expand_path if absolute_path.exist?
       rescue
-        nil
+        []
       end.map(&:to_s)
 
-      return [] if expected_paths.empty?
-
       changed_paths.select { |path| expected_paths.include?(path.expand_path.to_s) }
     end