Overhaul version checkers to prefer Version to str

src/ocrmypdf/_exec/ghostscript.py

@@ -70,8 +70,8 @@ log.addFilter(DuplicateFilter(log))
 GS = 'gswin64c' if os.name == 'nt' else 'gs'
 
 
-def version():
-    return get_version(GS)
+def version() -> Version:
+    return Version(get_version(GS))
 
 
 def _gs_error_reported(stream) -> bool:
@@ -216,8 +216,7 @@ def generate_pdfa(
             "-dAutoFilterGrayImages=true",
         ]
 
-    strategy = 'LeaveColorUnchanged'
-    gs_version = Version(version())
+    gs_version = version()
     if gs_version == Version('9.56.0'):
         # 9.56.0 breaks our OCR, should be fixed in 9.56.1
         # https://bugs.ghostscript.com/show_bug.cgi?id=705187

src/ocrmypdf/_exec/jbig2enc.py

@@ -7,12 +7,14 @@ from __future__ import annotations
 
 from subprocess import PIPE
 
+from packaging.version import Version
+
 from ocrmypdf.exceptions import MissingDependencyError
 from ocrmypdf.subprocess import get_version, run
 
 
-def version():
-    return get_version('jbig2', regex=r'jbig2enc (\d+(\.\d+)*).*')
+def version() -> Version:
+    return Version(get_version('jbig2', regex=r'jbig2enc (\d+(\.\d+)*).*'))
 
 
 def available():

src/ocrmypdf/_exec/pngquant.py

@@ -10,14 +10,15 @@ from io import BytesIO
 from pathlib import Path
 from subprocess import PIPE
 
+from packaging.version import Version
 from PIL import Image
 
 from ocrmypdf.exceptions import MissingDependencyError
 from ocrmypdf.subprocess import get_version, run
 
 
-def version():
-    return get_version('pngquant', regex=r'(\d+(\.\d+)*).*')
+def version() -> Version:
+    return Version(get_version('pngquant', regex=r'(\d+(\.\d+)*).*'))
 
 
 def available():

src/ocrmypdf/_exec/tesseract.py

@@ -113,13 +113,13 @@ class TesseractVersion(Version):
     )
 
 
-def version() -> str:
-    return get_version('tesseract', regex=r'tesseract\s(.+)')
+def version() -> Version:
+    return TesseractVersion(get_version('tesseract', regex=r'tesseract\s(.+)'))
 
 
 def has_thresholding() -> bool:
     """Does Tesseract have -c thresholding method capability?"""
-    return version() >= '5.0'
+    return version() >= Version('5.0')
 
 
 def get_languages() -> set[str]:

src/ocrmypdf/_exec/unpaper.py

@@ -15,6 +15,7 @@ from pathlib import Path
 from subprocess import PIPE, STDOUT
 from typing import Iterator, Union
 
+from packaging.version import Version
 from PIL import Image
 
 from ocrmypdf.exceptions import MissingDependencyError, SubprocessOutputError
@@ -67,8 +68,8 @@ class UnpaperImageTooLargeError(Exception):
         super().__init__(self.message)
 
 
-def version() -> str:
-    return get_version('unpaper')
+def version() -> Version:
+    return Version(get_version('unpaper'))
 
 
 SUPPORTED_MODES = {'1', 'L', 'RGB'}

src/ocrmypdf/builtin_plugins/tesseract_ocr.py

@@ -212,7 +212,7 @@ class TesseractOcrEngine(OcrEngine):
 
     @staticmethod
     def version():
-        return tesseract.version()
+        return str(tesseract.version())
 
     @staticmethod
     def creator_tag(options):

src/ocrmypdf/subprocess/__init__.py

@@ -292,16 +292,12 @@ def _error_old_version(
     _error_trailer(**locals())
 
 
-def _remove_leading_v(s: str) -> str:
-    return s.removeprefix('v')
-
-
 def check_external_program(
     *,
     program: str,
     package: str,
-    version_checker: Callable[[], str],
-    need_version: str,
+    version_checker: Callable[[], Version],
+    need_version: str | Version,
     required_for: str | None = None,
     recommended: bool = False,
     version_parser: type[Version] = Version,
@@ -321,6 +317,8 @@ def check_external_program(
         version_parser: A class that should be used to parse and compare version
             numbers. Used when version numbers do not follow standard conventions.
     """
+    if not isinstance(need_version, Version):
+        need_version = version_parser(need_version)
     try:
         found_version = version_checker()
     except (CalledProcessError, FileNotFoundError) as e:
@@ -334,11 +332,10 @@ def check_external_program(
             raise
         return
 
-    found_version = _remove_leading_v(found_version)
-    need_version = _remove_leading_v(need_version)
-
-    if found_version and version_parser(found_version) < version_parser(need_version):
-        _error_old_version(program, package, need_version, found_version, required_for)
+    if found_version and found_version < need_version:
+        _error_old_version(
+            program, package, str(need_version), str(found_version), required_for
+        )
         if not recommended:
             raise MissingDependencyError(program)