Blacklist Ghostscript 9.24 due to regressions

As per issue #291. Forced push to remove a copyrighted test file that was
accidentally included.

docs/release_notes.rst

@@ -13,6 +13,12 @@ Note that it is licensed under GPLv3, so scripts that ``import ocrmypdf`` and ar
    find:    [^`]\#([0-9]{1,3})[^0-9]
    replace: `#$1 <https://github.com/jbarlow83/OCRmyPDF/issues/$1>`_
 
+v7.0.6
+------
+
+-   Blacklist Ghostscript 9.24, now that 9.25 is available and fixes many regressions in 9.24.
+
+
 v7.0.5
 ------
 

src/ocrmypdf/__main__.py

@@ -858,6 +858,14 @@ def run_pipeline():
             "security vulnerabilities with certain malformed PDFs. Consider "
             "upgrading to version 7.0.0 or newer.".format(qpdf.version()))
 
+    if ghostscript.version() == '9.24':
+        complain(
+            "Ghostscript 9.24 contains serious regressions and is not "
+            "supported. Please upgrade to Ghostscript 9.25 or use an older "
+            "version."
+        )
+        return ExitCode.missing_dependency
+
     # Any changes to options will not take effect for options that are already
     # bound to function parameters in the pipeline. (For example
     # options.input_file, options.pdf_renderer are already bound.)

src/ocrmypdf/_pipeline.py

@@ -789,8 +789,8 @@ def generate_postscript_stub(
                 v.encode('ascii', errors='strict')
         except UnicodeEncodeError:
             log.warning(
-                "Ghostscript 9.24 does not support Unicode strings in metadata."
-                " These will be converted to ASCII if possible."
+                "Ghostscript 9.24+ does not support Unicode strings in "
+                " metadata. These will be converted to ASCII if possible."
             )
 
     generate_pdfa_ps(output_file, pdfmark, ascii_docinfo=ascii_docinfo)

src/ocrmypdf/exec/ghostscript.py

@@ -42,7 +42,8 @@ def jpeg_passthrough_available():
     https://bugs.ghostscript.com/show_bug.cgi?id=699216
 
     The issue was fixed for 9.24, hence that is the first version we consider
-    the feature available.
+    the feature available. (However, we don't use 9.24 at all, so the first
+    version that allows JPEG passthrough is 9.25.
 
     """
     return version() >= '9.24'