Review OSError exceptions handling (#1080)

- Replace obsolete `IOError` (Python 2) with `OSError`,
  cf https://docs.python.org/3/library/exceptions.html#OSError.
- Improve `OSError` catches at different places, simplifying
  the code.

httpie/cli/argparser.py

@@ -176,7 +176,7 @@ class HTTPieArgumentParser(argparse.ArgumentParser):
             self.args.output_file.seek(0)
             try:
                 self.args.output_file.truncate()
-            except IOError as e:
+            except OSError as e:
                 if e.errno == errno.EINVAL:
                     # E.g. /dev/null on Linux.
                     pass

httpie/cli/argtypes.py

@@ -180,8 +180,8 @@ def readable_file_arg(filename):
     try:
         with open(filename, 'rb'):
             return filename
-    except IOError as ex:
-        raise argparse.ArgumentTypeError(f'{filename}: {ex.args[1]}')
+    except OSError as ex:
+        raise argparse.ArgumentTypeError(f'{ex.filename}: {ex.strerror}')
 
 
 def parse_format_options(s: str, defaults: Optional[dict]) -> dict:

httpie/cli/requestitems.py

@@ -106,7 +106,7 @@ def process_file_upload_arg(arg: KeyValueArg) -> Tuple[str, IO, str]:
     mime_type = parts[1] if len(parts) > 1 else None
     try:
         f = open(os.path.expanduser(filename), 'rb')
-    except IOError as e:
+    except OSError as e:
         raise ParseError(f'{arg.orig!r}: {e}')
     return (
         os.path.basename(filename),
@@ -139,7 +139,7 @@ def load_text_file(item: KeyValueArg) -> str:
     try:
         with open(os.path.expanduser(path), 'rb') as f:
             return f.read().decode()
-    except IOError as e:
+    except OSError as e:
         raise ParseError(f'{item.orig!r}: {e}')
     except UnicodeDecodeError:
         raise ParseError(

httpie/config.py

@@ -72,11 +72,7 @@ class BaseConfigDict(dict):
         self.path = path
 
     def ensure_directory(self):
-        try:
-            self.path.parent.mkdir(mode=0o700, parents=True)
-        except OSError as e:
-            if e.errno != errno.EEXIST:
-                raise
+        self.path.parent.mkdir(mode=0o700, parents=True, exist_ok=True)
 
     def is_new(self) -> bool:
         return not self.path.exists()
@@ -92,9 +88,10 @@ class BaseConfigDict(dict):
                         f'invalid {config_type} file: {e} [{self.path}]'
                     )
                 self.update(data)
-        except IOError as e:
-            if e.errno != errno.ENOENT:
-                raise ConfigFileError(f'cannot read {config_type} file: {e}')
+        except FileNotFoundError:
+            pass
+        except OSError as e:
+            raise ConfigFileError(f'cannot read {config_type} file: {e}')
 
     def save(self, fail_silently=False):
         self['__meta__'] = {
@@ -116,16 +113,16 @@ class BaseConfigDict(dict):
         )
         try:
             self.path.write_text(json_string + '\n')
-        except IOError:
+        except OSError:
             if not fail_silently:
                 raise
 
     def delete(self):
         try:
+            # TODO: use `missing_ok` kwarg when supporting Python 3.8+ only
             self.path.unlink()
-        except OSError as e:
-            if e.errno != errno.ENOENT:
-                raise
+        except FileNotFoundError:
+            pass
 
 
 class Config(BaseConfigDict):

httpie/downloads.py

@@ -267,7 +267,7 @@ class Downloader:
                 try:
                     self._output_file.seek(0)
                     self._output_file.truncate()
-                except IOError:
+                except OSError:
                     pass  # stdout
 
         self.status.started(

httpie/output/writer.py

@@ -42,7 +42,7 @@ def write_message(
             write_stream_with_colors_win_py3(**write_stream_kwargs)
         else:
             write_stream(**write_stream_kwargs)
-    except IOError as e:
+    except OSError as e:
         show_traceback = args.debug or args.traceback
         if not show_traceback and e.errno == errno.EPIPE:
             # Ignore broken pipes unless --traceback.

tests/test_ssl.py

@@ -76,7 +76,7 @@ class TestClientCert:
                  '--cert', '/__not_found__',
                  tolerate_error_exit_status=True)
         assert r.exit_status == ExitStatus.ERROR
-        assert 'No such file or directory' in r.stderr
+        assert '/__not_found__: No such file or directory' in r.stderr
 
     def test_cert_file_invalid(self, httpbin_secure):
         with pytest.raises(ssl_errors):
@@ -117,8 +117,8 @@ class TestServerCert:
             http(httpbin_secure_untrusted.url + '/get')
 
     def test_verify_custom_ca_bundle_invalid_path(self, httpbin_secure):
-        # since 2.14.0 requests raises IOError
-        with pytest.raises(ssl_errors + (IOError,)):
+        # since 2.14.0 requests raises IOError (an OSError subclass)
+        with pytest.raises(ssl_errors + (OSError,)):
             http(httpbin_secure.url + '/get', '--verify', '/__not_found__')
 
     def test_verify_custom_ca_bundle_invalid_bundle(self, httpbin_secure):