diff --git a/Library/Homebrew/utils/pypi.rb b/Library/Homebrew/utils/pypi.rb
index 403a5a642a..acc3573a6c 100644
--- a/Library/Homebrew/utils/pypi.rb
+++ b/Library/Homebrew/utils/pypi.rb
@@ -41,9 +41,6 @@ module PyPI
   def update_python_resources!(formula, version = nil, print_only: false, silent: false,
                                ignore_non_pypi_packages: false)
 
-    @pipgrip_installed ||= Formula["pipgrip"].any_version_installed?
-    odie '"pipgrip" must be installed (`brew install pipgrip`)' unless @pipgrip_installed
-
     # PyPI package name isn't always the same as the formula name. Try to infer from the URL.
     pypi_name = if formula.stable.url.start_with?(PYTHONHOSTED_URL_PREFIX)
       url_to_pypi_package_name formula.stable.url
@@ -66,6 +63,9 @@ module PyPI
       odie "\"#{formula.name}\" contains non-PyPI resources. Please update the resources manually."
     end
 
+    @pipgrip_installed ||= Formula["pipgrip"].any_version_installed?
+    odie '"pipgrip" must be installed (`brew install pipgrip`)' unless @pipgrip_installed
+
     ohai "Retrieving PyPI dependencies for \"#{pypi_name}==#{version}\"" if !print_only && !silent
     pipgrip_output = Utils.popen_read Formula["pipgrip"].bin/"pipgrip", "--json", "--no-cache-dir",
                                       "#{pypi_name}==#{version}"