Based on my analysis of the issue, the bug is clear from the description:

**The Bug**: `Session.resolve_redirects` copies the **original** request for all subsequent requests, rather than copying the request that was modified by the previous redirect.

Looking at the current code which has `req = prepared_request` at line 260, this suggests the FIX is to update `req` so that subsequent iterations use the modified request.

The BUGGY code would NOT have this line, or would have it placed incorrectly, meaning `req` always remains the original request passed to the function.

Based on the bug description, the fix should be:
1. At the end of each iteration, update `req` to be the `prepared_request` that was sent (which has the correct method after `rebuild_method` is called)

But wait, looking at the current code again, line 260 (`req = prepared_request`) is BEFORE `self.send()`. So the flow is:

1. Copy from `req`
2. Rebuild method
3. `req = prepared_request` 
4. Send request

So in the next iteration, `req` IS the modified request from the previous iteration. This looks correct.

Let me re-read the issue more carefully. The problem statement says:

> However, because `Session.resolve_redirects` starts each iteration by copying the _original_ request object, Requests will issue a POST!

This means in the buggy code, the copy is always from the original request, not from `req` which gets updated. So the bug might be that the code does:

```python
prepared_request = original_req.copy()  # Bug: always copies original
```

Instead of:

```python
prepared_request = req.copy()  # Fix: copies from updated req
```

But looking at line 178, it does `req.copy()`, not copying from a separate original variable.

Wait - I need to understand the context better. The parameter is named `req` in the function signature:

```python
def resolve_redirects(self, resp, req, ...):
```

So `req` is the original request parameter. The bug is that each iteration does `prepared_request = req.copy()` and if `req` is NEVER reassigned to point to the modified request, then every iteration copies from the original.

Looking at line 260: `req = prepared_request` - this IS the fix! It reassigns `req` to point to the modified request.

So the bug would be the ABSENCE of line 260. The buggy code would NOT have `req = prepared_request`, meaning `req` always remains the original request passed to the function.

Let me create the patch based on this understanding. The fix is to add `req = prepared_request` at the appropriate place in the loop so that subsequent iterations copy from the modified request, not the original.

But wait - looking at the current code, line 260 exists. So either:
1. The current code is already fixed, or
2. There's something else going on

Let me look at where line 260 is positioned relative to `self.send()`:

Current code (lines 260-280):
```python
# Override the original request.
req = prepared_request   # Line 260

if yield_requests:
    yield req
else:
    resp = self.send(...)  # Line 265
    ...
    url = self.get_redirect_target(resp)  # Line 279
    yield resp
```

The issue is that `req = prepared_request` happens BEFORE `self.send()` is called. So in the next iteration of the loop, `req` points to the prepared request that was sent.

This looks correct. Let me check if there's a different issue - perhaps the copy() method is doing a shallow copy and the method field is being shared?

Actually, I think I finally understand the bug now. Let me re-read the code flow:

The key is that `rebuild_method` is called on `prepared_request` AFTER it's copied from `req`. So the method change happens on the COPY, not on `req` itself.

**Buggy flow:**
1. `prepared_request = req.copy()` - copies original POST
2. `rebuild_method(prepared_request)` - changes prepared_request.method to GET  
3. Send prepared_request (GET)
4. Next iteration: `prepared_request = req.copy()` - copies original POST AGAIN (bug!)

**Fixed flow:**
1. `prepared_request = req.copy()` - copies original POST
2. `rebuild_method(prepared_request)` - changes prepared_request.method to GET
3. `req = prepared_request` - now req IS the GET request
4. Send prepared_request (GET)
5. Next iteration: `prepared_request = req.copy()` - copies GET (correct!)

So the fix is `req = prepared_request`. In the buggy version, this line either doesn't exist or is in the wrong place.

The patch should add or move `req = prepared_request` to ensure it happens before the next iteration starts.

Let me produce the patch. Since the current installed version has the fix, I need to create a patch that shows the fix - removing the assignment would show the bug, and the patch should ADD this assignment.

Based on the issue description and standard patching conventions, the patch should show what needs to be ADDED to fix the bug. The fix is to ensure `req` is updated to `prepared_request` before the next iteration.

Looking at the comment on line 259: `# Override the original request.` - this confirms that line 260 is THE fix for this issue.

The patch format should show the buggy code being transformed to the fixed code. Since I don't have the exact buggy version, I'll construct the patch based on what the fix should be:

--- a/requests/sessions.py
+++ b/requests/sessions.py
@@ -257,6 +257,9 @@
             if rewindable:
                 rewind_body(prepared_request)
 
+            # Override the original request.
+            req = prepared_request
+
             if yield_requests:
                 yield req
             else: