From feaa3640387fdfb2929cc2d99f18db804ffe1cee Mon Sep 17 00:00:00 2001
From: ringabout <43030857+ringabout@users.noreply.github.com>
Date: Fri, 5 Dec 2025 14:52:35 +0800
Subject: [PATCH] fixes #25306; Dangling pointers in stack traces with
 `-d:nimStackTraceOverride` (#25313)

fixes #25306

```nim
type
  StackTraceEntry* = object ## In debug mode exceptions store the stack trace that led
                            ## to them. A `StackTraceEntry` is a single entry of the
                            ## stack trace.
    procname*: cstring      ## Name of the proc that is currently executing.
    line*: int              ## Line number of the proc that is currently executing.
    filename*: cstring      ## Filename of the proc that is currently executing.
    when NimStackTraceMsgs:
      frameMsg*: string     ## When a stacktrace is generated in a given frame and
                            ## rendered at a later time, we should ensure the stacktrace
                            ## data isn't invalidated; any pointer into PFrame is
                            ## subject to being invalidated so shouldn't be stored.
    when defined(nimStackTraceOverride):
      programCounter*: uint ## Program counter - will be used to get the rest of the info,
                            ## when `$` is called on this type. We can't use
                            ## "cuintptr_t" in here.
      procnameStr*, filenameStr*: string ## GC-ed alternatives to "procname" and "filename"
```

(cherry picked from commit 0ea5f2625cc9015eb45fb0667370940514e9aed8)
---
 lib/system/stacktraces.nim | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/lib/system/stacktraces.nim b/lib/system/stacktraces.nim
index 7c8ab83c48..cdb24eaedf 100644
--- a/lib/system/stacktraces.nim
+++ b/lib/system/stacktraces.nim
@@ -29,6 +29,8 @@ when defined(nimStackTraceOverride):
       proc (programCounters: seq[cuintptr_t], maxLength: cint): seq[StackTraceEntry] {.
         nimcall, gcsafe, raises: [], tags: [], noinline.}
 
+
+
   # Default procedures (not normally used, because people opting in on this
   # override are supposed to register their own versions).
   var
@@ -65,6 +67,15 @@ when defined(nimStackTraceOverride):
     for i in 0..<programCounters.len:
       s.add(StackTraceEntry(programCounter: cast[uint](programCounters[i])))
 
+  proc patchStackTraceEntry(x: var StackTraceEntry) =
+    x.procname = x.procnameStr.cstring
+    x.filename = x.filenameStr.cstring
+
+  proc addStackTraceEntrySeq(result: var seq[StackTraceEntry]; s: seq[StackTraceEntry]) =
+    for i in 0..<s.len:
+      result.add(s[i])
+      patchStackTraceEntry(result[result.high])
+
   # We may have more stack trace lines in the output, due to inlined procedures.
   proc addDebuggingInfo*(s: seq[StackTraceEntry]): seq[StackTraceEntry] =
     var programCounters: seq[cuintptr_t]
@@ -75,10 +86,12 @@ when defined(nimStackTraceOverride):
       if entry.procname.isNil and entry.programCounter != 0:
         programCounters.add(cast[cuintptr_t](entry.programCounter))
       elif entry.procname.isNil and (entry.line == reraisedFromBegin or entry.line == reraisedFromEnd):
-        result.add(stackTraceOverrideGetDebuggingInfo(programCounters, maxStackTraceLines))
+        result.addStackTraceEntrySeq(stackTraceOverrideGetDebuggingInfo(programCounters, maxStackTraceLines))
         programCounters = @[]
         result.add(entry[])
+        patchStackTraceEntry(result[result.high])
       else:
         result.add(entry[])
+        patchStackTraceEntry(result[result.high])
     if programCounters.len > 0:
-      result.add(stackTraceOverrideGetDebuggingInfo(programCounters, maxStackTraceLines))
+      result.addStackTraceEntrySeq(stackTraceOverrideGetDebuggingInfo(programCounters, maxStackTraceLines))