Rename variable sometimes fails when using the LanguageServer #477

Ciprian Tomoiaga (@cipri-tom) commented on Thu Dec 06 2018

Environment data

• VS Code version: 1.29.1
• Extension version (available under the Extensions sidebar): 2018.11.0
• OS and version: macOS Mojave 10.14.1
• Python version (& distribution if applicable, e.g. Anaconda): python 3.6.4 64-bit conda
• Type of virtual environment used (N/A | venv | virtualenv | conda | ...): N/A
• Relevant/affected Python packages and their versions:
  • Microsoft Python Language Server version 0.1.60.0

Steps to reproduce:

1. Make new file, test.py
2. paste the following:

def iadd_no_overflow(a, b):
    """Perform `a += b` on integer numpy arrays without overflowing"""
    dest += src
    dest[dest < src] = np.iinfo(dest.dtype).max

Note the file is dirty (not saved). The same happens if the file is saved.

3. Place cursor on dest and hit F2 or choose Rename symbol. Enter a as name.

Expected behaviour

All occurences of dest are changed into a

Actual behaviour

Got a tooltip Cannot rename, and an error in the Output window:

Logs

Output for Python in the Output panel (View→Output, change the drop-down the upper-right of the Output panel to Python)

Starting Microsoft Python language server.
Microsoft Python Language Server version 0.1.60.0
Initializing for /Users/ciprian/miniconda3/bin/python
[Error - 12:12:43 PM] Request textDocument/rename failed.
  Message: Cannot rename
  Code: -32000 
   at Microsoft.Python.LanguageServer.Implementation.Server.Rename(RenameParams params, CancellationToken cancellationToken)
   at Microsoft.Python.LanguageServer.Implementation.LanguageServer.Rename(JToken token, CancellationToken cancellationToken)

Output from Console under the Developer Tools panel (toggle Developer Tools on under Help):

Nothing. I mean, there are some ERR but from before. I put a console.log and then reproduce the error and nothing new appears in the console.