Let curl_download handle HTTP 416 error.

Library/Homebrew/download_strategy.rb

@@ -331,21 +331,11 @@ class CurlDownloadStrategy < AbstractFileDownloadStrategy
     if cached_location.exist?
       puts "Already downloaded: #{cached_location}"
     else
-      had_incomplete_download = temporary_path.exist?
       begin
         _fetch
       rescue ErrorDuringExecution
-        # 33 == range not supported
-        # try wiping the incomplete download and retrying once
-        unless $CHILD_STATUS.exitstatus == 33 && had_incomplete_download
         raise CurlDownloadStrategyError, @url
       end
-
-        ohai "Trying a full download"
-        temporary_path.unlink
-        had_incomplete_download = false
-        retry
-      end
       ignore_interrupts { temporary_path.rename(cached_location) }
     end
   rescue CurlDownloadStrategyError

Library/Homebrew/utils/curl.rb

@@ -38,11 +38,14 @@ def curl(*args)
 end
 
 def curl_download(*args, to: nil, continue_at: "-", **options)
+  had_incomplete_download ||= File.exist?(to)
   curl("--location", "--remote-time", "--continue-at", continue_at.to_s, "--output", to, *args, **options)
 rescue ErrorDuringExecution
   # `curl` error 33: HTTP server doesn't seem to support byte ranges. Cannot resume.
-  if $CHILD_STATUS.exitstatus == 33 && continue_at == "-"
+  # HTTP status 416: Requested range not satisfiable
+  if ($CHILD_STATUS.exitstatus == 33 || had_incomplete_download) && continue_at == "-"
     continue_at = 0
+    had_incomplete_download = false
     retry
   end