From 536b6e2396042491068fda8536bfec5e38000985 Mon Sep 17 00:00:00 2001
From: Alyssa Ross <hi@alyssa.is>
Date: Thu, 5 Jan 2017 00:24:49 +0000
Subject: [PATCH] uses: properly handle recursive deps exceptions

Fixes #1776.

If any known formula had a dependency on an untapped tap,
Formula#recursive_dependencies would throw an exception, which would be
caught by the outer exception handler, causing the rest of the
dependencies for that formula to be skipped and incomplete output to be
generated.

To fix this, I added a check to avoid analysing the dependencies of
formulae from uninstalled taps.

Additionally, I removed the aforementioned outer exception handler added
in 5fdb89aed90f03413cdb21af430411c4a722876e, because the only other
place that should be capable of throwing such an exception is the
statement that was surrounded by another wider exception handler in
Homebrew/legacy-homebrew#40682.
---
 Library/Homebrew/cmd/uses.rb | 79 ++++++++++++++++++------------------
 1 file changed, 40 insertions(+), 39 deletions(-)

diff --git a/Library/Homebrew/cmd/uses.rb b/Library/Homebrew/cmd/uses.rb
index fb11a31a74..f9af367549 100644
--- a/Library/Homebrew/cmd/uses.rb
+++ b/Library/Homebrew/cmd/uses.rb
@@ -47,48 +47,49 @@ module Homebrew
 
     uses = formulae.select do |f|
       used_formulae.all? do |ff|
-        begin
-          if recursive
-            deps = f.recursive_dependencies do |dependent, dep|
-              if dep.recommended?
-                Dependency.prune if ignores.include?("recommended?") || dependent.build.without?(dep)
-              elsif dep.optional?
-                Dependency.prune if !includes.include?("optional?") && !dependent.build.with?(dep)
-              elsif dep.build?
-                Dependency.prune unless includes.include?("build?")
-              end
+        if recursive
+          deps = f.recursive_dependencies do |dependent, dep|
+            if dep.recommended?
+              Dependency.prune if ignores.include?("recommended?") || dependent.build.without?(dep)
+            elsif dep.optional?
+              Dependency.prune if !includes.include?("optional?") && !dependent.build.with?(dep)
+            elsif dep.build?
+              Dependency.prune unless includes.include?("build?")
             end
-            reqs = f.recursive_requirements do |dependent, req|
-              if req.recommended?
-                Requirement.prune if ignores.include?("recommended?") || dependent.build.without?(req)
-              elsif req.optional?
-                Requirement.prune if !includes.include?("optional?") && !dependent.build.with?(req)
-              elsif req.build?
-                Requirement.prune unless includes.include?("build?")
-              end
-            end
-          else
-            deps = f.deps.reject do |dep|
-              ignores.any? { |ignore| dep.send(ignore) } && !includes.any? { |include| dep.send(include) }
-            end
-            reqs = f.requirements.reject do |req|
-              ignores.any? { |ignore| req.send(ignore) } && !includes.any? { |include| req.send(include) }
-            end
-          end
-          next true if deps.any? do |dep|
-            begin
-              dep.to_formula.full_name == ff.full_name
-            rescue
-              dep.name == ff.name
-            end
-          end
 
-          reqs.any? do |req|
-            req.name == ff.name || [ff.name, ff.full_name].include?(req.default_formula)
+            # If a tap isn't installed, we can't find the dependencies of one
+            # its formulae, and an exception will be thrown if we try.
+            if dep.is_a?(TapDependency) && !dep.tap.installed?
+              Dependency.keep_but_prune_recursive_deps
+            end
           end
-        rescue FormulaUnavailableError
-          # Silently ignore this case as we don't care about things used in
-          # taps that aren't currently tapped.
+          reqs = f.recursive_requirements do |dependent, req|
+            if req.recommended?
+              Requirement.prune if ignores.include?("recommended?") || dependent.build.without?(req)
+            elsif req.optional?
+              Requirement.prune if !includes.include?("optional?") && !dependent.build.with?(req)
+            elsif req.build?
+              Requirement.prune unless includes.include?("build?")
+            end
+          end
+        else
+          deps = f.deps.reject do |dep|
+            ignores.any? { |ignore| dep.send(ignore) } && !includes.any? { |include| dep.send(include) }
+          end
+          reqs = f.requirements.reject do |req|
+            ignores.any? { |ignore| req.send(ignore) } && !includes.any? { |include| req.send(include) }
+          end
+        end
+        next true if deps.any? do |dep|
+          begin
+            dep.to_formula.full_name == ff.full_name
+          rescue
+            dep.name == ff.name
+          end
+        end
+
+        reqs.any? do |req|
+          req.name == ff.name || [ff.name, ff.full_name].include?(req.default_formula)
         end
       end
     end