From ef97f3cf2b0a6f411de0ff02ae9bd0fba2d11923 Mon Sep 17 00:00:00 2001
From: volognamor <romangolov2001@gmail.com>
Date: Fri, 17 Jul 2026 21:49:28 +0300
Subject: [PATCH] Windows: fix non-ASCII chat prompt corruption (ANSI codepage
 vs UTF-8)
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coli passes the chat prompt to glm.exe through the PROMPT/COLI_PROMPT
environment variable. On Windows, plain getenv() is populated by the CRT
from the ANSI-codepage view of the environment block, not UTF-8 — so any
non-ASCII prompt text (Cyrillic, CJK, ...) is silently mangled before the
byte-level tokenizer ever sees it, even though the parent process (coli's
Python subprocess call) sets the value correctly via the wide env block.

Add compat_getenv_utf8() in compat.h: reads the variable through
GetEnvironmentVariableW and converts straight to UTF-8, bypassing the ANSI
codepage entirely. No-op passthrough to getenv() on non-Windows platforms.
coli_user_prompt() in glm.c now uses it for both COLI_PROMPT and PROMPT.

Verified: tiny-oracle self-test still 32/32 after rebuild, and a real run
against the full GLM-5.2-int4 model with a Cyrillic prompt now round-trips
correctly end to end (input echoed intact, coherent Cyrillic output),
where it previously produced replacement-character garbage on both input
and output.
---
 c/compat.h | 31 +++++++++++++++++++++++++++++++
 c/glm.c    |  4 ++--
 2 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/c/compat.h b/c/compat.h
index 82de8b6..06779e0 100644
--- a/c/compat.h
+++ b/c/compat.h
@@ -304,8 +304,39 @@ static inline int compat_setenv(const char *name, const char *value, int overwri
 }
 #define setenv(name,value,overwrite) compat_setenv(name,value,overwrite)
 
+/* --- getenv_utf8: read an env var as UTF-8, not through the ANSI codepage ---
+ * Plain getenv()/_environ are populated by the CRT from the ANSI-codepage view
+ * of the process environment block, not UTF-8. A parent that hands the child a
+ * Unicode value via CreateProcessW's wide env block (e.g. Python's subprocess
+ * module, which coli uses to pass the chat prompt) round-trips correctly only
+ * through GetEnvironmentVariableW; going through narrow getenv() re-encodes it
+ * via CP_ACP first, so any non-ASCII prompt text (Cyrillic, CJK, ...) comes out
+ * corrupted before the byte-level tokenizer ever sees it. Read the wide value
+ * directly and convert straight to UTF-8, bypassing the ANSI codepage entirely.
+ * Returned buffer is intentionally leaked: called a handful of times at
+ * startup, lives for the process. */
+static inline const char *compat_getenv_utf8(const char *name){
+    wchar_t wname[64];
+    if(MultiByteToWideChar(CP_UTF8, 0, name, -1, wname, 64) <= 0) return getenv(name);
+    DWORD need = GetEnvironmentVariableW(wname, NULL, 0);
+    if(!need) return NULL;
+    wchar_t *wval = (wchar_t*)malloc(need * sizeof(wchar_t));
+    if(!wval) return NULL;
+    GetEnvironmentVariableW(wname, wval, need);
+    int blen = WideCharToMultiByte(CP_UTF8, 0, wval, -1, NULL, 0, NULL, NULL);
+    char *val = blen>0 ? (char*)malloc((size_t)blen) : NULL;
+    if(val) WideCharToMultiByte(CP_UTF8, 0, wval, -1, val, blen, NULL, NULL);
+    free(wval);
+    return val;
+}
+#define getenv_utf8(name) compat_getenv_utf8(name)
+
 #endif /* _WIN32 */
 
+#ifndef getenv_utf8
+#define getenv_utf8(name) getenv(name)
+#endif
+
 /* --- compat_aligned_free su piattaforme diverse da Windows ---
  * Su Linux/macOS, posix_memalign usa free() normale. */
 #ifndef compat_aligned_free
diff --git a/c/glm.c b/c/glm.c
index 00c7076..b0e419c 100644
--- a/c/glm.c
+++ b/c/glm.c
@@ -5701,9 +5701,9 @@ static void cap_for_ram(Model *m, double ram_gb, int ebits, int max_ctx){
  * self-test, and would "generate" from "$P$G". So on Windows a PROMPT carrying
  * cmd's $-metacodes is ignored; set COLI_PROMPT to pass a real prompt from cmd. */
 static const char *coli_user_prompt(void){
-    const char *p = getenv("COLI_PROMPT");
+    const char *p = getenv_utf8("COLI_PROMPT");
     if(p) return p;
-    p = getenv("PROMPT");
+    p = getenv_utf8("PROMPT");
 #ifdef _WIN32
     if(p) for(const char *q=p; q[0]; q++)
         if(q[0]=='$' && q[1] && strchr("ABCDEFGHLNPQSTV_+|$", q[1]&~0x20)){ p=NULL; break; }