bug#73355: 29.4; eglot-rename reports success when it shouldn't

[Joost Kremers <joostkremers@fastmail.fm>]

On Sat, Sep 21 2024, João Távora wrote:
> I have this some version of this server somewhere, maybe I can reproduce,
> but as always better to follow the instructions in the manual
> https://joaotavora.github.io/eglot/#Troubleshooting-Eglot and give the
> remaining items of a full MRE.

OK, here goes:

1. The relevant lines from the events buffer (apologies for the long lines):

```
[jsonrpc] e[00:13:52.047] --> textDocument/rename[27] {"jsonrpc":"2.0","id":27,"method":"textDocument/rename","params":{"textDocument":{"uri":"file:///home/joost/Projects/Python/pyscratch/src/search.py"},"position":{"line":88,"character":29},"newName":"seq"}}
[jsonrpc] e[00:13:52.049]   <-- textDocument/rename[27] #[0 "\300\301\302\303\304\305\257\6\207" [:id 27 :jsonrpc "2.0" :result nil] 14]
```

Contrast this with a call to 'eglot-rename' that *does* yield changes:

```
[jsonrpc] e[00:16:34.228] --> textDocument/rename[68] {"jsonrpc":"2.0","id":68,"method":"textDocument/rename","params":{"textDocument":{"uri":"file:///home/joost/Projects/Python/pyscratch/src/search.py"},"position":{"line":87,"character":8},"newName":"arr"}}
[jsonrpc] e[00:16:34.235]   <-- textDocument/rename[68] #[0 "\323\312\324\325\326\327\313\330\313\302\303\304\305\306\307\300\331\301\314F\310\300\332\301\314FF\257\6\302\303\304\305\306\307\300\333\301\315F\310\300\334\301\315FF\257\6\302\303\304\305\306\307\300\311\301\316F\310\300\312\301\316FF\257\6\302\303\304\305\306\307\300\317\301\320F\310\300\311\301\320FF\257\6\302\303\304\305\306\307\300\317\301\321F\310\300\311\301\321FF\257\6\302\303\304\305\306\307\300\335\301\322F\310\300\336\301\322FF\257\6&\6\337\340\341\342\343FF!D\257\6\207" [:character :line :annotationId "default" :newText "arr" :range :end :start 71 68 vector 87 88 89 74 90 91 93 :id :jsonrpc "2.0" :result :documentChanges :edits 11 8 32 29 50 47 :textDocument :uri "file:///home/joost/Projects/Python/pyscratch/src/search.py" :version nil] 34]
```

Looks like basedpyright is reporting that it didn't make any changes in the
first case (':results nil').

2. Emacs did not signal an error.

3. The language server I used is basedpyright, which can be installed from
PyPI with the usual tools. I have version 1.17.5, which is the latest
release.

To configure Eglot to use it, the basedpyright docs suggest to add the
following to one's init file (which is what I do):

```
(add-to-list 'eglot-server-programs
             '((python-mode python-ts-mode)
               "basedpyright-langserver" "--stdio"))
```

See https://docs.basedpyright.com/#/installation for details.

4. For a minimal project, all you'll need is a single Python file with a
single function, which can be as simple as this:

```
def some_func():
    a: int = 5
    b: int = d + 7
    c: int = d + 13
    print(b+c)
```

Try to rename the two occurrences of 'd' to 'a'.

The code snippet in my original email will also do, even if basedpyright
will report a bunch of errors in it for undefined functions. Those don't
affect the rename.

5. Emacs: 29.4, Eglot 1.17 (from GNU ELPA), basedpyright 1.17.5.

6. I assume the issue is so straightforward that there's no need for a
recipe that's more detailed than the above.

Thanks,

Joost


-- 
Joost Kremers
Life has its moments