From 73b91f58d0bfa387880ab94ccb20afd08f634c53 Mon Sep 17 00:00:00 2001
From: Javier Dehesa <javidcf@gmail.com>
Date: Fri, 25 Nov 2022 15:10:05 +0000
Subject: [PATCH] Support arbitrary number of loaded modules on Windows

Changed the TKinter module loading function for Windows to support the rare (but possible) case of having more than 1024 modules loaded. This is an adaptation of the same fix that was added to Matplotlib in [PR #22445](https://github.com/matplotlib/matplotlib/pull/22445).
---
 src/Tk/tkImaging.c | 28 ++++++++++++++++++++--------
 1 file changed, 20 insertions(+), 8 deletions(-)

diff --git a/src/Tk/tkImaging.c b/src/Tk/tkImaging.c
index 16b9a2edd..58ca23a56 100644
--- a/src/Tk/tkImaging.c
+++ b/src/Tk/tkImaging.c
@@ -310,7 +310,7 @@ load_tkinter_funcs(void) {
      * Return 0 for success, non-zero for failure.
      */
 
-    HMODULE hMods[1024];
+    HMODULE* hMods = NULL;
     HANDLE hProcess;
     DWORD cbNeeded;
     unsigned int i;
@@ -327,33 +327,45 @@ load_tkinter_funcs(void) {
     /* Returns pseudo-handle that does not need to be closed */
     hProcess = GetCurrentProcess();
 
+    /* Allocate module handlers array */
+    if (!EnumProcessModules(hProcess, NULL, 0, &cbNeeded)) {
+        PyErr_SetFromWindowsErr(0);
+        return 1;
+    }
+    if (!(hMods = static_cast<HMODULE*>(malloc(cbNeeded)))) {
+        PyErr_NoMemory();
+        return 1;
+    }
+
     /* Iterate through modules in this process looking for Tcl / Tk names */
-    if (EnumProcessModules(hProcess, hMods, sizeof(hMods), &cbNeeded)) {
+    if (EnumProcessModules(hProcess, hMods, cbNeeded, &cbNeeded)) {
         for (i = 0; i < (cbNeeded / sizeof(HMODULE)); i++) {
             if (!found_tcl) {
                 found_tcl = get_tcl(hMods[i]);
                 if (found_tcl == -1) {
-                    return 1;
+                    goto exit;
                 }
             }
             if (!found_tk) {
                 found_tk = get_tk(hMods[i]);
                 if (found_tk == -1) {
-                    return 1;
+                    goto exit;
                 }
             }
             if (found_tcl && found_tk) {
-                return 0;
+                goto exit;
             }
         }
     }
 
-    if (found_tcl == 0) {
+exit:
+    free(hMods);
+    if (found_tcl != 1) {
         PyErr_SetString(PyExc_RuntimeError, "Could not find Tcl routines");
-    } else {
+    } else if (found_tk != 1) {
         PyErr_SetString(PyExc_RuntimeError, "Could not find Tk routines");
     }
-    return 1;
+    return int((found_tcl != 1) && (found_tk != 1));
 }
 
 #else /* not Windows */