Use interleaved output for ErrorDuringExecution.

Library/Homebrew/cask/lib/hbc/system_command.rb

@@ -19,6 +19,7 @@ module Hbc
     end
 
     def run!
+      @merged_output = []
       @processed_output = { stdout: "", stderr: "" }
       odebug command.shelljoin
 
@@ -27,9 +28,11 @@ module Hbc
         when :stdout
           puts line.chomp if print_stdout?
           processed_output[:stdout] << line
+          @merged_output << [:stdout, line]
         when :stderr
           $stderr.puts Formatter.error(line.chomp) if print_stderr?
           processed_output[:stderr] << line
+          @merged_output << [:stderr, line]
         end
       end
 
@@ -85,9 +88,8 @@ module Hbc
     def assert_success
       return if processed_status&.success?
       raise ErrorDuringExecution.new(command,
-                                     stdout: processed_output[:stdout],
-                                     stderr: processed_output[:stderr],
-                                     status: processed_status)
+                                     status: processed_status,
+                                     output: @merged_output)
     end
 
     def expanded_args

Library/Homebrew/exceptions.rb

@@ -526,19 +526,21 @@ end
 
 # raised by safe_system in utils.rb
 class ErrorDuringExecution < RuntimeError
-  def initialize(cmd, status:, stdout: nil, stderr: nil)
+  def initialize(cmd, status:, output: nil)
     s = "Failure while executing; `#{cmd.shelljoin.gsub(/\\=/, "=")}` exited with #{status.exitstatus}."
 
-    if stdout
-      s << "==> Standard Output of failed command:\n"
-      s << stdout
-      s << "\n" unless stdout.end_with?("\n")
-    end
+    unless [*output].empty?
+      format_output_line = lambda do |type, line|
+        if type == :stderr
+          Formatter.error(line)
+        else
+          line
+        end
+      end
 
-    if stderr
-      s << "==> Standard Error of failed command:\n"
-      s << stderr
-      s << "\n" unless stderr.end_with?("\n")
+      s << " Here's the output:\n"
+      s << output.map(&format_output_line).join
+      s << "\n" unless s.end_with?("\n")
     end
 
     super s

Library/Homebrew/extend/os/linux/keg_relocate.rb

@@ -21,7 +21,7 @@ class Keg
     # Skip ELF files that do not have a .dynstr section.
     return if ["cannot find section .dynstr", "strange: no string table"].include?(old_rpath)
     unless $CHILD_STATUS.success?
-      raise ErrorDuringExecution.new(cmd_rpath, stdout: old_rpath, status: $CHILD_STATUS)
+      raise ErrorDuringExecution.new(cmd_rpath, status: $CHILD_STATUS, output: [:stdout, old_rpath])
     end
 
     rpath = old_rpath