From 9471bc8921054a58685fcc3317da966cae21e4fb Mon Sep 17 00:00:00 2001
From: "James R. Barlow" <jim@purplerock.ca>
Date: Fri, 10 Apr 2020 13:42:33 -0700
Subject: [PATCH] Fix versions with leading v, e.g. v5.0

---
 src/ocrmypdf/exec/__init__.py | 8 ++++++++
 tests/test_validation.py      | 6 ++++++
 2 files changed, 14 insertions(+)

diff --git a/src/ocrmypdf/exec/__init__.py b/src/ocrmypdf/exec/__init__.py
index 1fb3b047..92e4d956 100644
--- a/src/ocrmypdf/exec/__init__.py
+++ b/src/ocrmypdf/exec/__init__.py
@@ -271,6 +271,14 @@ def check_external_program(
             raise MissingDependencyError()
         return
 
+    def remove_leading_v(s):
+        if s.startswith('v'):
+            return s[1:]
+        return s
+
+    found_version = remove_leading_v(found_version)
+    need_version = remove_leading_v(need_version)
+
     if LooseVersion(found_version) < LooseVersion(need_version):
         _error_old_version(program, package, need_version, found_version, required_for)
         if not recommended:
diff --git a/tests/test_validation.py b/tests/test_validation.py
index 9fc5fe39..af1eadea 100644
--- a/tests/test_validation.py
+++ b/tests/test_validation.py
@@ -197,6 +197,12 @@ def test_version_comparison():
         version_checker=lambda: '4.0.0-beta.1',
         need_version='4.0.0',
     )
+    vd.check_external_program(
+        program="tesseract",
+        package="tesseract",
+        version_checker=lambda: 'v5.0.0-alpha.20200201',
+        need_version='4.0.0',
+    )
     with pytest.raises(MissingDependencyError):
         vd.check_external_program(
             program="dummy_fails",