Repository: spyder-ide/spyder

Issue:
Error when checking for updates finishes with pip installations
## Description

### What steps will reproduce the problem?

<!--- You can use Markdown here --->

I checkout a different branch in Git Bash from Git4Windows. When I came back I had this window here.

### Traceback
```python-traceback
Traceback (most recent call last):
  File "C:\Users\miker\Envs\mkeveprodmanager\lib\site-packages\spyder\plugins\application\container.py", line 331, in _check_updates_ready
    msg = header + content + footer
UnboundLocalError: local variable 'content' referenced before assignment
```

## Versions

* Spyder version: 5.4.1  (pip)
* Python version: 3.9.13 64-bit
* Qt version: 5.15.2
* PyQt5 version: 5.15.7
* Operating System: Windows 10

### Dependencies

```
# Mandatory:
atomicwrites >=1.2.0          :  1.4.1 (OK)
chardet >=2.0.0               :  5.1.0 (OK)
cloudpickle >=0.5.0           :  2.2.0 (OK)
cookiecutter >=1.6.0          :  2.1.1 (OK)
diff_match_patch >=20181111   :  20200713 (OK)
intervaltree >=3.0.2          :  3.1.0 (OK)
IPython >=7.31.1;<9.0.0       :  8.7.0 (OK)
jedi >=0.17.2;<0.19.0         :  0.18.2 (OK)
jellyfish >=0.7               :  0.9.0 (OK)
jsonschema >=3.2.0            :  4.17.3 (OK)
keyring >=17.0.0              :  23.13.1 (OK)
nbconvert >=4.0               :  7.2.7 (OK)
numpydoc >=0.6.0              :  1.5.0 (OK)
paramiko >=2.4.0              :  2.12.0 (OK)
parso >=0.7.0;<0.9.0          :  0.8.3 (OK)
pexpect >=4.4.0               :  4.8.0 (OK)
pickleshare >=0.4             :  0.7.5 (OK)
psutil >=5.3                  :  5.9.4 (OK)
pygments >=2.0                :  2.13.0 (OK)
pylint >=2.5.0;<3.0           :  2.15.9 (OK)
pylint_venv >=2.1.1           :  2.3.0 (OK)
pyls_spyder >=0.4.0           :  0.4.0 (OK)
pylsp >=1.7.0;<1.8.0          :  1.7.0 (OK)
pylsp_black >=1.2.0           :  1.2.1 (OK)
qdarkstyle >=3.0.2;<3.1.0     :  3.0.3 (OK)
qstylizer >=0.2.2             :  0.2.2 (OK)
qtawesome >=1.2.1             :  1.2.2 (OK)
qtconsole >=5.4.0;<5.5.0      :  5.4.0 (OK)
qtpy >=2.1.0                  :  2.3.0 (OK)
rtree >=0.9.7                 :  1.0.1 (OK)
setuptools >=49.6.0           :  65.5.1 (OK)
sphinx >=0.6.6                :  6.0.0 (OK)
spyder_kernels >=2.4.1;<2.5.0 :  2.4.1 (OK)
textdistance >=4.2.0          :  4.5.0 (OK)
three_merge >=0.1.1           :  0.1.1 (OK)
watchdog >=0.10.3             :  2.2.0 (OK)
zmq >=22.1.0                  :  24.0.1 (OK)

# Optional:
cython >=0.21                 :  None (NOK)
matplotlib >=3.0.0            :  None (NOK)
numpy >=1.7                   :  1.24.1 (OK)
pandas >=1.1.1                :  None (NOK)
scipy >=0.17.0                :  1.9.3 (OK)
sympy >=0.7.3                 :  None (NOK)
```



Discussion:
Hi @moxon1982 thank you for the feedback! I think this is an issue regarding the update functionality we added for the standalone installers when using it on pip installations. It is not related to git but a process that is launched to check for updates when you have the `Preferences > Application > Advanced settings > Check for updates on startup` enabled.

As a workaround for the moment, you can disabled that option and the error message should not appear when starting Spyder.

Let us know if the info above helps!
I use this now as indication that I need to run
pip install spyder --upgrade

Resolving patch:
diff --git a/spyder/plugins/application/container.py b/spyder/plugins/application/container.py
--- a/spyder/plugins/application/container.py
+++ b/spyder/plugins/application/container.py
@@ -305,6 +305,7 @@ def _check_updates_ready(self):
                 header = _("<b>Spyder {} is available!</b> "
                            "<i>(you have {})</i><br><br>").format(
                     latest_release, __version__)
+                content = ""
                 footer = _(
                     "For more information, visit our "
                     "<a href=\"{}\">installation guide</a>."


Test patch: