Support loading version from a file

2 files changed, 30 insertions, 0 deletions

diff --git a/setuptools/config.py b/setuptools/config.py
index 8eddcae8..6343840e 100644
--- a/setuptools/config.py
+++ b/setuptools/config.py
@@ -7,6 +7,7 @@ from functools import partial
 from importlib import import_module
 
 from distutils.errors import DistutilsOptionError, DistutilsFileError
+from setuptools.extern.packaging.version import LegacyVersion, parse
 from setuptools.extern.six import string_types
 
 
@@ -427,6 +428,18 @@ class ConfigMetadataHandler(ConfigHandler):
         :rtype: str
 
         """
+        version = self._parse_file(value)
+
+        if version != value:
+            version = version.strip()
+            # Be strict about versions loaded from file because it's easy to
+            # accidentally include newlines and other unintended content
+            if isinstance(parse(version), LegacyVersion):
+                raise DistutilsOptionError('Version loaded from %s does not comply with PEP 440: %s' % (
+                    value, version
+                ))
+            return version
+
         version = self._parse_attr(value)
 
         if callable(version):
diff --git a/setuptools/tests/test_config.py b/setuptools/tests/test_config.py
index abb953a8..17ac09c8 100644
--- a/setuptools/tests/test_config.py
+++ b/setuptools/tests/test_config.py
@@ -268,6 +268,23 @@ class TestMetadata:
         with get_dist(tmpdir) as dist:
             assert dist.metadata.version == '2016.11.26'
 
+    def test_version_file(self, tmpdir):
+
+        _, config = fake_env(
+            tmpdir,
+            '[metadata]\n'
+            'version = file: fake_package/version.txt\n'
+        )
+        tmpdir.join('fake_package', 'version.txt').write('1.2.3\n')
+
+        with get_dist(tmpdir) as dist:
+            assert dist.metadata.version == '1.2.3'
+
+        tmpdir.join('fake_package', 'version.txt').write('1.2.3\n4.5.6\n')
+        with pytest.raises(DistutilsOptionError):
+            with get_dist(tmpdir) as dist:
+                _ = dist.metadata.version
+
     def test_unknown_meta_item(self, tmpdir):
 
         fake_env(