[Python-checkins] bpo-39393: Misleading error message on dependent DLL resolution failure (GH-18093)

[Miss Islington (bot)]

https://github.com/python/cpython/commit/46735c7e101753769e31c69a36d0030bb056a162
commit: 46735c7e101753769e31c69a36d0030bb056a162
branch: 3.8
author: Miss Islington (bot) <31488909+miss-islington at users.noreply.github.com>
committer: GitHub <noreply at github.com>
date: 2020-01-28T02:00:16-08:00
summary:

bpo-39393: Misleading error message on dependent DLL resolution failure (GH-18093)

(cherry picked from commit 13c1c3556f2c12d0be2af890fabfbf44280b845c)

Co-authored-by: Zackery Spytz <zspytz at gmail.com>

files:
A Misc/NEWS.d/next/Windows/2020-01-20-23-42-53.bpo-39393.gWlJDG.rst
M Modules/_ctypes/callproc.c

diff --git a/Misc/NEWS.d/next/Windows/2020-01-20-23-42-53.bpo-39393.gWlJDG.rst b/Misc/NEWS.d/next/Windows/2020-01-20-23-42-53.bpo-39393.gWlJDG.rst
new file mode 100644
index 0000000000000..025b7e96a6e74
--- /dev/null
+++ b/Misc/NEWS.d/next/Windows/2020-01-20-23-42-53.bpo-39393.gWlJDG.rst
@@ -0,0 +1,2 @@
+Improve the error message when attempting to load a DLL with unresolved
+dependencies.
diff --git a/Modules/_ctypes/callproc.c b/Modules/_ctypes/callproc.c
index 77492e650ea48..4027bdb622750 100644
--- a/Modules/_ctypes/callproc.c
+++ b/Modules/_ctypes/callproc.c
@@ -1311,8 +1311,9 @@ static PyObject *load_library(PyObject *self, PyObject *args)
 
     if (err == ERROR_MOD_NOT_FOUND) {
         PyErr_Format(PyExc_FileNotFoundError,
-                     ("Could not find module '%.500S'. Try using "
-                      "the full path with constructor syntax."),
+                     ("Could not find module '%.500S' (or one of its "
+                      "dependencies). Try using the full path with "
+                      "constructor syntax."),
                      nameobj);
         return NULL;
     } else if (err) {