Windows: fail gracefully when undname.exe is not found (#19600)

* Windows: fail gracefully when undname.exe is not found

* Edit error message.

diff --git a/tensorflow/tools/def_file_filter/def_file_filter_configure.bzl b/tensorflow/tools/def_file_filter/def_file_filter_configure.bzl
index 47539b2..f8f63e2 100644 (file)
--- a/tensorflow/tools/def_file_filter/def_file_filter_configure.bzl
+++ b/tensorflow/tools/def_file_filter/def_file_filter_configure.bzl
@@ -31,7 +31,11 @@ def _def_file_filter_configure_impl(repository_ctx):
   vc_path = find_vc_path(repository_ctx)
   if vc_path == "visual-studio-not-found":
     auto_configure_fail("Visual C++ build tools not found on your machine")
-  undname_bin_path = find_msvc_tool(repository_ctx, vc_path, "undname.exe").replace("\\", "\\\\")
+
+  undname = find_msvc_tool(repository_ctx, vc_path, "undname.exe")
+  if undname == None:
+    auto_configure_fail("Couldn't find undname.exe under %s, please check your VC installation and set BAZEL_VC environment variable correctly." % vc_path)
+  undname_bin_path = undname.replace("\\", "\\\\")
 
   repository_ctx.template(
     "def_file_filter.py",