Fix for when 'trailer' is indented (#535)

* Fix for when trailer is indented

* Store stripped line

* This commit breaks things...

* Or maybe this one breaks things?

* Remove commented code because no longer used.

* Add CHANGELOG.md

* Add poetry venv management files to gitignore since I started using poetry to manage the python envs for this project

Co-authored-by: Pieter Marsman <pietermarsman@gmail.com>

.gitignore

@@ -17,5 +17,9 @@ tests/*.xml
 tests/*.txt
 .idea/
 .tox/
+
+# python venv management tools
 Pipfile
-Pipfile.lock
+Pipfile.lock
+pyproject.toml
+poetry.lock

CHANGELOG.md

@@ -8,6 +8,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 ### Fixed
 - Fix issue of TypeError: cannot unpack non-iterable PDFObjRef object, when unpacking the value of 'DW2' ([#529](https://github.com/pdfminer/pdfminer.six/pull/529))
 - `PermissionError` when creating temporary filepaths on windows when running tests ([#469](https://github.com/pdfminer/pdfminer.six/issues/469))
+- Detecting trailer correctly when surrounded with needless whitespace ([#535](https://github.com/pdfminer/pdfminer.six/pull/535))
 - Fix `.paint_path` logic for handling single line segments and extracting point-on-curve positions of Beziér path commands ([#530](https://github.com/pdfminer/pdfminer.six/pull/530))
 
 ## Removed

pdfminer/pdfdocument.py

@@ -93,16 +93,15 @@ class PDFXRef(PDFBaseXRef):
         while True:
             try:
                 (pos, line) = parser.nextline()
-                if not line.strip():
+                line = line.strip()
+                if not line:
                     continue
             except PSEOF:
                 raise PDFNoValidXRef('Unexpected EOF - file corrupted?')
-            if not line:
-                raise PDFNoValidXRef('Premature eof: %r' % parser)
             if line.startswith(b'trailer'):
                 parser.seek(pos)
                 break
-            f = line.strip().split(b' ')
+            f = line.split(b' ')
             if len(f) != 2:
                 error_msg = 'Trailer not found: {!r}: line={!r}'\
                     .format(parser, line)
@@ -116,9 +115,10 @@ class PDFXRef(PDFBaseXRef):
             for objid in range(start, start+nobjs):
                 try:
                     (_, line) = parser.nextline()
+                    line = line.strip()
                 except PSEOF:
                     raise PDFNoValidXRef('Unexpected EOF - file corrupted?')
-                f = line.strip().split(b' ')
+                f = line.split(b' ')
                 if len(f) != 3:
                     error_msg = 'Invalid XRef format: {!r}, line={!r}'\
                         .format(parser, line)