bpo-34604: Use %R because of invisible characters or trailing whitespaces. (GH-9165). (GH-10947)

(cherry picked from commit 34c7f0c)

Co-authored-by: William Grzybowski <[email protected]>

Author: serhiy-storchaka

Misc/NEWS.d/next/Library/2018-09-07-10-16-34.bpo-34604.xL7-kG.rst

@@ -0,0 +1,3 @@
+Fix possible mojibake in the error message of `pwd.getpwnam` and
+`grp.getgrnam` using string representation because of invisible characters
+or trailing whitespaces. Patch by William Grzybowski.

Modules/grpmodule.c

@@ -156,7 +156,7 @@ grp_getgrnam_impl(PyObject *module, PyObject *name)
         goto out;
 
     if ((p = getgrnam(name_chars)) == NULL) {
-        PyErr_Format(PyExc_KeyError, "getgrnam(): name not found: %S", name);
+        PyErr_Format(PyExc_KeyError, "getgrnam(): name not found: %R", name);
         goto out;
     }
     retval = mkgrent(p);

Modules/pwdmodule.c

@@ -163,7 +163,7 @@ pwd_getpwnam_impl(PyObject *module, PyObject *arg)
         goto out;
     if ((p = getpwnam(name)) == NULL) {
         PyErr_Format(PyExc_KeyError,
-                     "getpwnam(): name not found: %S", arg);
+                     "getpwnam(): name not found: %R", arg);
         goto out;
     }
     retval = mkpwent(p);