Recursively expand requirements in FormulaInstaller

Currently FormulaInstaller "forgets" about the requirements of
dependencies, as dependencies are recursively expanded by the first
FormulaInstaller instance, and then ignored by subsequent instances to
prevent duplicate installation attempts. These requirements then have
their messages displayed, but the fatal check is skipped and thus no
exception is raised.

Now that we have Formula#recursive_requirements, we can mirror what we
are doing with dependencies and recursively expand requirements up
front.

While at it, fix a bug in determining Requirement equality that resulted
in unique requirements being eliminated from a formula's set of
recursive requirements.

Fixes Homebrew/homebrew#12290.
Fixes Homebrew/homebrew#14084.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/Library/Homebrew/dependencies.rb b/Library/Homebrew/dependencies.rb
index c4b8f0b67..44584242a 100644
--- a/Library/Homebrew/dependencies.rb
+++ b/Library/Homebrew/dependencies.rb
@@ -137,7 +137,7 @@ class Requirement
   end
 
   def hash
-    @message.hash
+    message.hash
   end
 end
 
@@ -194,7 +194,6 @@ end
 # This requirement is used to require an X11 implementation,
 # optionally with a minimum version number.
 class X11Dependency < Requirement
-
   def initialize min_version=nil
     @min_version = min_version
   end
@@ -216,6 +215,9 @@ class X11Dependency < Requirement
     ENV.x11
   end
 
+  def hash
+    "X11".hash
+  end
 end