diff --git a/Library/Homebrew/build.rb b/Library/Homebrew/build.rb
index a0d453e50f..4dfaf9e7e0 100644
--- a/Library/Homebrew/build.rb
+++ b/Library/Homebrew/build.rb
@@ -11,8 +11,6 @@ require "extend/ENV"
 require "debrew"
 require "fcntl"
 require "socket"
-require "json"
-require "json/add/core"
 
 class Build
   attr_reader :formula, :deps, :reqs
@@ -192,17 +190,7 @@ begin
   build   = Build.new(formula, options)
   build.install
 rescue Exception => e # rubocop:disable Lint/RescueException
-  error_hash = JSON.parse e.to_json
-
-  # Special case: We need to toss our build state into the error hash
-  # for proper analytics reporting and sensible error messages.
-  if e.is_a?(BuildError)
-    error_hash["cmd"] = e.cmd
-    error_hash["args"] = e.args
-    error_hash["env"] = e.env
-  end
-
-  error_pipe.write error_hash.to_json
+  Marshal.dump(e, error_pipe)
   error_pipe.close
   exit! 1
 end
diff --git a/Library/Homebrew/dev-cmd/test.rb b/Library/Homebrew/dev-cmd/test.rb
index 310ab94a6c..d21a62cde5 100644
--- a/Library/Homebrew/dev-cmd/test.rb
+++ b/Library/Homebrew/dev-cmd/test.rb
@@ -93,14 +93,12 @@ module Homebrew
             exec(*args)
           end
         end
-      rescue ChildProcessError => e
+      rescue ::Test::Unit::AssertionFailedError => e
         ofail "#{f.full_name}: failed"
-        case e.inner["json_class"]
-        when "Test::Unit::AssertionFailedError"
-          puts e.inner["m"]
-        else
-          puts e.inner["json_class"], e.backtrace
-        end
+        puts e.message
+      rescue Exception => e # rubocop:disable Lint/RescueException
+        ofail "#{f.full_name}: failed"
+        puts e, e.backtrace
       ensure
         ENV.replace(env)
       end
diff --git a/Library/Homebrew/exceptions.rb b/Library/Homebrew/exceptions.rb
index ab6f5c6724..dc3f5f9e36 100644
--- a/Library/Homebrew/exceptions.rb
+++ b/Library/Homebrew/exceptions.rb
@@ -352,16 +352,14 @@ class FormulaAmbiguousPythonError < RuntimeError
 end
 
 class BuildError < RuntimeError
-  attr_reader :formula, :cmd, :args, :env
+  attr_reader :formula, :env
   attr_accessor :options
 
   def initialize(formula, cmd, args, env)
     @formula = formula
-    @cmd = cmd
-    @args = args
     @env = env
-    pretty_args = args.map { |arg| arg.to_s.gsub " ", "\\ " }.join(" ")
-    super "Failed executing: #{cmd} #{pretty_args}"
+    args = args.map { |arg| arg.to_s.gsub " ", "\\ " }.join(" ")
+    super "Failed executing: #{cmd} #{args}"
   end
 
   def issues
@@ -598,20 +596,3 @@ class BottleFormulaUnavailableError < RuntimeError
     EOS
   end
 end
-
-# Raised when a child process sends us an exception over its error pipe.
-class ChildProcessError < RuntimeError
-  attr_reader :inner
-
-  def initialize(inner)
-    @inner = inner
-
-    super <<~EOS
-      An exception occured within a build process:
-        #{inner["json_class"]}: #{inner["m"]}
-    EOS
-
-    # Clobber our real (but irrelevant) backtrace with that of the inner exception.
-    set_backtrace inner["b"]
-  end
-end
diff --git a/Library/Homebrew/formula_installer.rb b/Library/Homebrew/formula_installer.rb
index f0c834500f..66a44a9cde 100644
--- a/Library/Homebrew/formula_installer.rb
+++ b/Library/Homebrew/formula_installer.rb
@@ -763,25 +763,14 @@ class FormulaInstaller
       raise "Empty installation"
     end
   rescue Exception => e # rubocop:disable Lint/RescueException
-    # If we've rescued a ChildProcessError and that ChildProcessError
-    # contains a BuildError, then we reconstruct the inner build error
-    # to make analytics happy.
-    if e.is_a?(ChildProcessError) && e.inner["json_class"] == "BuildError"
-      build_error = BuildError.new(formula, e["cmd"], e["args"], e["env"])
-      build_error.set_backtrace e.backtrace
-      build_error.options = display_options(formula)
-
-      e = build_error
-    end
-
+    e.options = display_options(formula) if e.is_a?(BuildError)
     ignore_interrupts do
       # any exceptions must leave us with nothing installed
       formula.update_head_version
       formula.prefix.rmtree if formula.prefix.directory?
       formula.rack.rmdir_if_possible
     end
-
-    raise e
+    raise
   end
 
   def link(keg)
diff --git a/Library/Homebrew/postinstall.rb b/Library/Homebrew/postinstall.rb
index 916dbada37..53a5b7e751 100644
--- a/Library/Homebrew/postinstall.rb
+++ b/Library/Homebrew/postinstall.rb
@@ -4,7 +4,6 @@ require "global"
 require "debrew"
 require "fcntl"
 require "socket"
-require "json/add/core"
 
 begin
   error_pipe = UNIXSocket.open(ENV["HOMEBREW_ERROR_PIPE"], &:recv_io)
@@ -16,7 +15,7 @@ begin
   formula.extend(Debrew::Formula) if ARGV.debug?
   formula.run_post_install
 rescue Exception => e # rubocop:disable Lint/RescueException
-  error_pipe.write e.to_json
+  Marshal.dump(e, error_pipe)
   error_pipe.close
   exit! 1
 end
diff --git a/Library/Homebrew/test.rb b/Library/Homebrew/test.rb
index 0c4b1bb36e..3d5e62a884 100644
--- a/Library/Homebrew/test.rb
+++ b/Library/Homebrew/test.rb
@@ -7,7 +7,6 @@ require "debrew"
 require "formula_assertions"
 require "fcntl"
 require "socket"
-require "json/add/core"
 
 TEST_TIMEOUT_SECONDS = 5 * 60
 
@@ -29,7 +28,7 @@ begin
     raise "test returned false" if formula.run_test == false
   end
 rescue Exception => e # rubocop:disable Lint/RescueException
-  error_pipe.write e.to_json
+  Marshal.dump(e, error_pipe)
   error_pipe.close
   exit! 1
 end
diff --git a/Library/Homebrew/utils/fork.rb b/Library/Homebrew/utils/fork.rb
index bf4e84143d..5087ca716c 100644
--- a/Library/Homebrew/utils/fork.rb
+++ b/Library/Homebrew/utils/fork.rb
@@ -1,7 +1,5 @@
 require "fcntl"
 require "socket"
-require "json"
-require "json/add/core"
 
 module Utils
   def self.safe_fork(&_block)
@@ -17,7 +15,7 @@ module Utils
             write.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC)
             yield
           rescue Exception => e # rubocop:disable Lint/RescueException
-            write.write e.to_json
+            Marshal.dump(e, write)
             write.close
             exit!
           else
@@ -38,7 +36,7 @@ module Utils
           data = read.read
           read.close
           Process.wait(pid) unless socket.nil?
-          raise ChildProcessError, JSON.parse(data) unless data.nil? || data.empty?
+          raise Marshal.load(data) unless data.nil? || data.empty? # rubocop:disable Security/MarshalLoad
           raise Interrupt if $CHILD_STATUS.exitstatus == 130
           raise "Forked child process failed: #{$CHILD_STATUS}" unless $CHILD_STATUS.success?
         end