uses: harden against missing formulae.

1 files changed, 11 insertions, 6 deletions

diff --git a/Library/Homebrew/cmd/uses.rb b/Library/Homebrew/cmd/uses.rb
index 249c41ba3..1c029b0f0 100644
--- a/Library/Homebrew/cmd/uses.rb
+++ b/Library/Homebrew/cmd/uses.rb
@@ -14,12 +14,17 @@ module Homebrew
 
     uses = formulae.select do |f|
       used_formulae.all? do |ff|
-        if recursive
-          f.recursive_dependencies.any? { |dep| dep.to_formula.name == ff.name } ||
-            f.recursive_requirements.any? { |req| req.name == ff.name }
-        else
-          f.deps.any? { |dep| dep.to_formula.name == ff.name } ||
-            f.requirements.any? { |req| req.name == ff.name }
+        begin
+          if recursive
+            f.recursive_dependencies.any? { |dep| dep.to_formula.name == ff.name } ||
+              f.recursive_requirements.any? { |req| req.name == ff.name }
+          else
+            f.deps.any? { |dep| dep.to_formula.name == ff.name } ||
+              f.requirements.any? { |req| req.name == ff.name }
+          end
+        rescue FormulaUnavailableError => e
+          # Silently ignore this case as we don't care about things used in
+          # taps that aren't currently tapped.
         end
       end
     end