Warn of unknown version range options

conans/model/version_range.py

@@ -95,8 +95,12 @@ def __init__(self, expression):
                 prereleases = True
                 break
             else:
+                t = t.strip()
                 from conan.api.output import ConanOutput
-                ConanOutput().warning(f'Unrecognized version range option "{t}" in "{expression}"')
+                if len(t) == 0 or t[0].isalpha():
+                    ConanOutput().warning(f'Unrecognized version range option "{t}" in "{expression}"')
+                else:
+                    ConanOutput().error(f'"{t}" in version range "{expression}" is not a valid option')
         version_expr = tokens[0]
         self.condition_sets = []
         for alternative in version_expr.split("||"):

conans/test/integration/graph/core/test_version_ranges.py

@@ -418,6 +418,9 @@ def test_different_user_channel_resolved_correctly():
 
 def test_unknown_options():
     c = TestClient()
-    c.save({"conanfile.py": GenConanfile("pkg", "1.0").with_requirement("lib/[>1.2, <1.4]")})
-    c.run("install .", assert_error=True)
-    assert 'Unrecognized version range option " <1.4" in ">1.2, <1.4"' in c.out
+
+    c.run("graph info --requires=lib/[>1.2,<1.4]", assert_error=True)
+    assert 'ERROR: "<1.4" in version range ">1.2,<1.4" is not a valid option' in c.out
+
+    c.run("graph info --requires=lib/[>1.2,unknown_conf]", assert_error=True)
+    assert 'WARN: Unrecognized version range option "unknown_conf" in ">1.2,unknown_conf"' in c.out