refactor(txt.py): fix exception2text import, improve performance and cleanup

Fix missing traceback import in exception2text() so the fallback path
works instead of being dead code. Replace O(n²) string concatenation
in filter_mltext() with list comprehension. Simplify nested ternary
in extract_str(). Remove unused Python 2 type aliases and outdated
comments.

Author: markuslf

CHANGELOG.md

@@ -25,6 +25,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * base.py: remove unused `collections` import
 * base.py: strip trailing semicolons in `get_perfdata()` output
 * db_sqlite.py: reduce unnecessary dictionary object creation
+* txt.py: improve `filter_mltext()` performance (avoid O(n²) string concatenation)
+* txt.py: improve readability of `extract_str()` fallback logic
+* txt.py: remove unused Python 2 type aliases and outdated comments
 * human.py: pre-compute mappings as module constants
 * powershell.py: `run_ps()` now always returns a dict
 * winrm.py: make `run_cmd()` and `run_ps()` JEA-aware
@@ -34,6 +37,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 * base.py: fix `get_table()` using wrong separator for the second data row when called without a header
 * powershell.py: fix outdated shebang line
+* txt.py: fix `exception2text()` missing `traceback` import (fallback path was dead code)
 * txt.py: fix `sanitize_sensitive_data()` replacing the key name instead of the secret value
 * winrm.py: pass parameters correctly in `run_cmd()` when using pypsrp
 

txt.py

@@ -19,16 +19,14 @@
 
 import codecs
 import re
+import traceback
 try:
     codecs.lookup_error('surrogateescape')
     HAS_SURROGATEESCAPE = True
 except LookupError:
     HAS_SURROGATEESCAPE = False
 import operator
 
-string_types = str
-integer_types = int
-class_types = type
 text_type = str
 binary_type = bytes
 
@@ -196,7 +194,11 @@ def extract_str(s, from_txt, to_txt, include_fromto=False, be_tolerant=True):
     if pos2 != -1:
         end = pos2 + len(to_txt) if include_fromto else pos2
         return s[start:end]
-    return s[pos1:] if be_tolerant and include_fromto else s[pos1 + len(from_txt):] if be_tolerant else ''
+    if not be_tolerant:
+        return ''
+    if include_fromto:
+        return s[pos1:]
+    return s[pos1 + len(from_txt):]
 
 
 def filter_mltext(_input, ignore):
@@ -238,11 +240,11 @@ def filter_mltext(_input, ignore):
     >>> filter_mltext(s, ['ipsum'])
     ''
     """
-    filtered_input = ''
-    for line in _input.splitlines():
-        if not any(i_line in line for i_line in ignore):
-            filtered_input += line + '\n'
-    return filtered_input
+    lines = [
+        line for line in _input.splitlines()
+        if not any(i_line in line for i_line in ignore)
+    ]
+    return '\n'.join(lines) + '\n' if lines else ''
 
 
 def match_regex(regex, string, key=''):
@@ -520,8 +522,7 @@ def to_bytes(obj, encoding='utf-8', errors=None, nonstring='simplerepr'):
     elif nonstring == 'passthru':
         return obj
     elif nonstring == 'empty':
-        # python2.4 doesn't have b''
-        return to_bytes('')
+        return b''
     elif nonstring == 'strict':
         raise TypeError('obj must be a string type')
     else:
@@ -640,4 +641,3 @@ def uniq(string):
 
 
 to_native = to_text
-# PY2: to_native = to_bytes