Warn when requires-python patch version isn't specified

Warn when requires-python is set to an exact value (==) and doesn't include a patch (so it'll get set to 0)

crates/uv-resolver/src/requires_python.rs

@@ -248,6 +248,18 @@ impl RequiresPython {
         self.range.lower().as_ref() == Bound::Unbounded
     }
 
+    /// Returns `true` if the `Requires-Python` specifier is set to a specific version
+    /// without a patch version. (e.g. `==3.10`)
+    pub fn is_matching_without_patch(&self) -> bool {
+        match self.range.lower().as_ref() {
+            Bound::Included(version) => {
+                version.release().len() == 2
+                    && self.range.upper().as_ref() == Bound::Included(version)
+            }
+            _ => false,
+        }
+    }
+
     /// Returns the [`RequiresPythonBound`] truncated to the major and minor version.
     pub fn bound_major_minor(&self) -> LowerBound {
         match self.range.lower().as_ref() {

crates/uv-resolver/src/requires_python/tests.rs

@@ -114,3 +114,26 @@ fn upper_bound_ordering() {
         }
     }
 }
+
+#[test]
+fn is_matching_without_patch() {
+    let test_cases = [
+        ("==3.12", true),
+        ("==2.7", true),
+        ("==3.10, <3.11", true),
+        ("==3.10, <=3.11", true),
+        ("==3.12.1", false),
+        ("==3.12.*", false),
+        ("==3.*", false),
+        (">=3.10", false),
+        (">3.9", false),
+        ("<4.0", false),
+        (">=3.10, <3.11", false),
+        ("", false),
+    ];
+    for (version, expected) in test_cases {
+        let version_specifiers = VersionSpecifiers::from_str(version).unwrap();
+        let requires_python = RequiresPython::from_specifiers(&version_specifiers).unwrap();
+        assert_eq!(requires_python.is_matching_without_patch(), expected);
+    }
+}

crates/uv/src/commands/project/lock.rs

@@ -336,6 +336,8 @@ async fn do_lock(
             let default =
                 RequiresPython::greater_than_equal_version(&interpreter.python_minor_version());
             warn_user_once!("The workspace `requires-python` value does not contain a lower bound: `{requires_python}`. Set a lower bound to indicate the minimum compatible Python version (e.g., `{default}`).");
+        } else if requires_python.is_matching_without_patch() {
+            warn_user_once!("The workspace `requires-python` value does not have a patch version: `{requires_python}`. It will be interpreted as `{requires_python}.0`. Did you mean `{requires_python}.*`?");
         }
         requires_python
     } else {