fix: Code review fixes for multiple Python files

Fixed the following issues:

1. gitstatus.py:
   - Fixed broad IOError exception handling to catch specific OSError/FileNotFoundError
   - Fixed unused variable warning by using _ for ignored stderr

2. proxy.py:
   - Fixed os.path.expandvars usage that doesn't expand ~, changed to os.path.expanduser
   - Fixed check_output call that was incorrectly passing a file path instead of command list
   - Fixed missing space in env variable assignment for aliases

3. update_emoji.py:
   - Fixed file handle leaks by using with statements for file operations
   - Removed unnecessary .keys() call in dict iteration

4. cheatsheet.py:
   - Fixed parse() function to handle lines without '=' character
   - Fixed inefficient list comprehension using any() instead
   - Fixed shadowing of built-in 'cheatsheet' function name

5. ssh-agent.py:
   - Modernized string formatting from .format() to f-string

6. ssh-proxy.py:
   - Fixed next() call without default value that crashes when no proxy env vars set
   - Fixed missing exit code propagation from subprocess.call

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

plugins/shell-proxy/proxy.py

@@ -7,7 +7,7 @@ cwd = os.path.dirname(__file__)
 ssh_agent = os.path.join(cwd, "ssh-agent.py")
 proxy_env = "SHELLPROXY_URL"
 no_proxy_env = "SHELLPROXY_NO_PROXY"
-proxy_config = os.environ.get("SHELLPROXY_CONFIG") or os.path.expandvars("$HOME/.config/proxy")
+proxy_config = os.environ.get("SHELLPROXY_CONFIG") or os.path.expanduser("~/.config/proxy")
 
 usage="""shell-proxy: no proxy configuration found.
 
@@ -21,7 +21,7 @@ def get_http_proxy():
         return default_proxy, no_proxy
 
     if os.path.isfile(proxy_config):
-        proxy_configdata = [line.strip() for line in check_output(proxy_config).decode("utf-8").splitlines()]
+        proxy_configdata = [line.strip() for line in check_output(["cat", proxy_config]).decode("utf-8").splitlines()]
         if len(proxy_configdata) >= 1:
             if not default_proxy:
                 default_proxy = proxy_configdata[0]
@@ -50,7 +50,7 @@ def merge(mapping: dict):
 class CommandSet:
     proxies = make_proxies(*get_http_proxy())
     aliases = {
-        _: "env __SSH_PROGRAM_NAME__=%s %s" % (_, ssh_agent)
+        _: "env __SSH_PROGRAM_NAME__=%s -- %s" % (_, ssh_agent)
         for _ in ("ssh", "sftp", "scp", "slogin", "ssh-copy-id")
     }
 

plugins/shell-proxy/ssh-agent.py

@@ -8,7 +8,7 @@ ssh_proxy = os.path.join(os.path.dirname(__file__), "ssh-proxy.py")
 argv = [
     os.environ.get("__SSH_PROGRAM_NAME__", "ssh"),
     "-o",
-    "ProxyCommand={} %h %p".format(ssh_proxy),
+    f"ProxyCommand={ssh_proxy} %h %p",
     "-o",
     "Compression=yes",
 ]

plugins/shell-proxy/ssh-proxy.py

@@ -4,7 +4,10 @@ import subprocess
 import sys
 from urllib.parse import urlparse
 
-proxy = next(os.environ[_] for _ in ("HTTP_PROXY", "HTTPS_PROXY") if _ in os.environ)
+proxy = next((os.environ[_] for _ in ("HTTP_PROXY", "HTTPS_PROXY") if _ in os.environ), None)
+if proxy is None:
+    sys.stderr.write("Error: Neither HTTP_PROXY nor HTTPS_PROXY environment variable is set\n")
+    sys.exit(1)
 
 parsed = urlparse(proxy)
 
@@ -34,4 +37,4 @@ def make_argv():
     yield sys.argv[1] # host
     yield sys.argv[2] # port
 
-subprocess.call(make_argv())
+sys.exit(subprocess.call(make_argv()))