Add support for python_version in ... markers

crates/pep508-rs/src/marker/algebra.rs

@@ -168,11 +168,32 @@ impl InternerGuard<'_> {
                 ),
                 Err(node) => return node,
             },
+            MarkerExpression::VersionIn {
+                key: MarkerValueVersion::PythonVersion,
+                versions,
+                negated,
+            } => match Edges::from_python_versions(versions, negated) {
+                Ok(edges) => (
+                    Variable::Version(MarkerValueVersion::PythonFullVersion),
+                    edges,
+                ),
+                Err(node) => return node,
+            },
             // A variable representing the output of a version key. Edges correspond
             // to disjoint version ranges.
             MarkerExpression::Version { key, specifier } => {
                 (Variable::Version(key), Edges::from_specifier(specifier))
             }
+            // A variable representing the output of a version key. Edges correspond
+            // to disjoint version ranges.
+            MarkerExpression::VersionIn {
+                key,
+                versions,
+                negated,
+            } => (
+                Variable::Version(key),
+                Edges::from_versions(&versions, negated),
+            ),
             // The `in` and `contains` operators are a bit different than other operators.
             // In particular, they do not represent a particular value for the corresponding
             // variable, and can overlap. For example, `'nux' in os_name` and `os_name == 'Linux'`
@@ -587,6 +608,50 @@ impl Edges {
         }
     }
 
+    /// Returns an [`Edges`] where values in the given range are `true`.
+    ///
+    /// Only for use when the `key` is a `PythonVersion`. Casts to `PythonFullVersion`.
+    fn from_python_versions(versions: Vec<Version>, negated: bool) -> Result<Edges, NodeId> {
+        let mut range = Range::empty();
+
+        // TODO(zanieb): We need to make sure this is performant, repeated unions like this do not
+        // seem efficient.
+        for version in versions {
+            let specifier = VersionSpecifier::equals_version(version.clone());
+            let specifier = python_version_to_full_version(specifier)?;
+            let pubgrub_specifier =
+                PubGrubSpecifier::from_release_specifier(&normalize_specifier(specifier)).unwrap();
+            range = range.union(&pubgrub_specifier.into());
+        }
+
+        if negated {
+            range = range.complement();
+        }
+
+        Ok(Edges::Version {
+            edges: Edges::from_range(&range),
+        })
+    }
+
+    /// Returns an [`Edges`] where values in the given range are `true`.
+    fn from_versions(versions: &Vec<Version>, negated: bool) -> Edges {
+        let mut range = Range::empty();
+
+        // TODO(zanieb): We need to make sure this is performant, repeated unions like this do not
+        // seem efficient.
+        for version in versions {
+            range = range.union(&Range::singleton(version.clone()));
+        }
+
+        if negated {
+            range = range.complement();
+        }
+
+        Edges::Version {
+            edges: Edges::from_range(&range),
+        }
+    }
+
     /// Returns an [`Edges`] where values in the given range are `true`.
     fn from_range<T>(range: &Range<T>) -> SmallVec<(Range<T>, NodeId)>
     where

crates/pep508-rs/src/marker/parse.rs

@@ -132,7 +132,9 @@ pub(crate) fn parse_marker_key_op_value<T: Pep508Url>(
     // Convert a `<marker_value> <marker_op> <marker_value>` expression into it's
     // typed equivalent.
     let expr = match l_value {
-        // The only sound choice for this is `<version key> <version op> <quoted PEP 440 version>`
+        // Either:
+        // - `<version key> <version op> <quoted PEP 440 version>`
+        // - `<version key> in <list of quoted PEP 440 versions>` and ("not in")
         MarkerValue::MarkerEnvVersion(key) => {
             let MarkerValue::QuotedString(value) = r_value else {
                 reporter.report(
@@ -146,6 +148,12 @@ pub(crate) fn parse_marker_key_op_value<T: Pep508Url>(
                 return Ok(None);
             };
 
+            // Check for `in` and `not in` expressions
+            if let Some(expr) = parse_version_in_expr(key.clone(), operator, &value, reporter) {
+                return Ok(Some(expr));
+            }
+
+            // Otherwise, it's a normal version expression
             parse_version_expr(key.clone(), operator, &value, reporter)
         }
         // The only sound choice for this is `<env key> <op> <string>`
@@ -238,6 +246,72 @@ pub(crate) fn parse_marker_key_op_value<T: Pep508Url>(
     Ok(expr)
 }
 
+/// Creates an instance of [`MarkerExpression::VersionIn`] with the given values.
+///
+/// Some important caveats apply here.
+///
+/// While the specification defines this operation as a substring search, for versions, we use a
+/// version-aware match so we can perform algebra on the expressions. This means that some markers
+/// will not be evaluated according to the specification, but these marker expressions are
+/// relatively rare so the trade-off is acceptable.
+///
+/// The following limited expression is supported:
+///     
+///      [not] in '<version> [additional versions]'
+///
+/// where the version is PEP 440 compliant. Arbitrary whitespace is allowed between versions.
+///
+/// Returns `None` if the [`MarkerOperator`] is not relevant.
+/// Reports a warning if an invalid version is encountered, and returns `None`.
+fn parse_version_in_expr(
+    key: MarkerValueVersion,
+    operator: MarkerOperator,
+    value: &str,
+    reporter: &mut impl Reporter,
+) -> Option<MarkerExpression> {
+    if !matches!(operator, MarkerOperator::In | MarkerOperator::NotIn) {
+        return None;
+    }
+    let negated = matches!(operator, MarkerOperator::NotIn);
+
+    let mut cursor = Cursor::new(value);
+    let mut versions = Vec::new();
+
+    // Parse all of the values in the list as versions
+    loop {
+        // Allow arbitrary whitespace between versions
+        cursor.eat_whitespace();
+
+        let (start, len) = cursor.take_while(|c| !c.is_whitespace());
+        if len == 0 {
+            break;
+        }
+
+        let version = match Version::from_str(cursor.slice(start, len)) {
+            Ok(version) => version,
+            Err(err) => {
+                reporter.report(
+                    MarkerWarningKind::Pep440Error,
+                    format!(
+                        "Expected PEP 440 versions to compare with {key}, found {value},
+                        will be ignored: {err}"
+                    ),
+                );
+
+                return None;
+            }
+        };
+
+        versions.push(version);
+    }
+
+    Some(MarkerExpression::VersionIn {
+        key,
+        versions,
+        negated,
+    })
+}
+
 /// Creates an instance of [`MarkerExpression::Version`] with the given values.
 ///
 /// Reports a warning on failure, and returns `None`.

crates/pep508-rs/src/marker/simplify.rs

@@ -378,6 +378,22 @@ fn is_negation(left: &MarkerExpression, right: &MarkerExpression) -> bool {
                     .negate()
                     .is_some_and(|negated| negated == *specifier2.operator())
         }
+        MarkerExpression::VersionIn {
+            key,
+            versions,
+            negated,
+        } => {
+            let MarkerExpression::VersionIn {
+                key: key2,
+                versions: versions2,
+                negated: negated2,
+            } = right
+            else {
+                return false;
+            };
+
+            key == key2 && versions == versions2 && negated != negated2
+        }
         MarkerExpression::String {
             key,
             operator,

crates/pep508-rs/src/marker/tree.rs

@@ -3,6 +3,7 @@ use std::fmt::{self, Display, Formatter};
 use std::ops::{Bound, Deref};
 use std::str::FromStr;
 
+use itertools::Itertools;
 use pubgrub::Range;
 #[cfg(feature = "pyo3")]
 use pyo3::{basic::CompareOp, pyclass, pymethods};
@@ -436,6 +437,19 @@ pub enum MarkerExpression {
         key: MarkerValueVersion,
         specifier: VersionSpecifier,
     },
+    /// A version in list expression, e.g. `<version key> in <quoted list of PEP 440 versions>`.
+    ///
+    /// A special case of [`MarkerExpression::String`] with the [`MarkerOperator::In`] operator for
+    /// [`MarkerValueVersion`] values.
+    ///
+    /// See [`parse::parse_version_in_expr`] for details on the supported syntax.
+    ///
+    /// Negated expressions, using "not in" are represented using `negated = true`.
+    VersionIn {
+        key: MarkerValueVersion,
+        versions: Vec<Version>,
+        negated: bool,
+    },
     /// An string marker comparison, e.g. `sys_platform == '...'`.
     ///
     /// Inverted string expressions, e.g `'...' == sys_platform`, are also normalized to this form.
@@ -534,6 +548,15 @@ impl Display for MarkerExpression {
                 }
                 write!(f, "{key} {op} '{version}'")
             }
+            MarkerExpression::VersionIn {
+                key,
+                versions,
+                negated,
+            } => {
+                let op = if *negated { "not in" } else { "in" };
+                let versions = versions.iter().map(ToString::to_string).join(" ");
+                write!(f, "{key} {op} '{versions}'")
+            }
             MarkerExpression::String {
                 key,
                 operator,
@@ -1542,6 +1565,69 @@ mod test {
         assert!(!marker3.evaluate(&env37, &[]));
     }
 
+    #[test]
+    fn test_version_in_evaluation() {
+        let env27 = MarkerEnvironment::try_from(MarkerEnvironmentBuilder {
+            implementation_name: "",
+            implementation_version: "2.7",
+            os_name: "linux",
+            platform_machine: "",
+            platform_python_implementation: "",
+            platform_release: "",
+            platform_system: "",
+            platform_version: "",
+            python_full_version: "2.7",
+            python_version: "2.7",
+            sys_platform: "linux",
+        })
+        .unwrap();
+        let env37 = env37();
+
+        let marker = MarkerTree::from_str("python_version in \"2.7 3.2 3.3\"").unwrap();
+        assert!(marker.evaluate(&env27, &[]));
+        assert!(!marker.evaluate(&env37, &[]));
+
+        let marker = MarkerTree::from_str("python_version in \"2.7 3.7\"").unwrap();
+        assert!(marker.evaluate(&env27, &[]));
+        assert!(marker.evaluate(&env37, &[]));
+
+        let marker = MarkerTree::from_str("python_version in \"2.4 3.8 4.0\"").unwrap();
+        assert!(!marker.evaluate(&env27, &[]));
+        assert!(!marker.evaluate(&env37, &[]));
+
+        let marker = MarkerTree::from_str("python_version not in \"2.7 3.2 3.3\"").unwrap();
+        assert!(!marker.evaluate(&env27, &[]));
+        assert!(marker.evaluate(&env37, &[]));
+
+        let marker = MarkerTree::from_str("python_version not in \"2.7 3.7\"").unwrap();
+        assert!(!marker.evaluate(&env27, &[]));
+        assert!(!marker.evaluate(&env37, &[]));
+
+        let marker = MarkerTree::from_str("python_version not in \"2.4 3.8 4.0\"").unwrap();
+        assert!(marker.evaluate(&env27, &[]));
+        assert!(marker.evaluate(&env37, &[]));
+
+        let marker = MarkerTree::from_str("python_full_version in \"2.7\"").unwrap();
+        assert!(marker.evaluate(&env27, &[]));
+        assert!(!marker.evaluate(&env37, &[]));
+
+        let marker = MarkerTree::from_str("implementation_version in \"2.7 3.2 3.3\"").unwrap();
+        assert!(marker.evaluate(&env27, &[]));
+        assert!(!marker.evaluate(&env37, &[]));
+
+        let marker = MarkerTree::from_str("implementation_version in \"2.7 3.7\"").unwrap();
+        assert!(marker.evaluate(&env27, &[]));
+        assert!(marker.evaluate(&env37, &[]));
+
+        let marker = MarkerTree::from_str("implementation_version not in \"2.7 3.7\"").unwrap();
+        assert!(!marker.evaluate(&env27, &[]));
+        assert!(!marker.evaluate(&env37, &[]));
+
+        let marker = MarkerTree::from_str("implementation_version not in \"2.4 3.8 4.0\"").unwrap();
+        assert!(marker.evaluate(&env27, &[]));
+        assert!(marker.evaluate(&env37, &[]));
+    }
+
     #[test]
     #[cfg(feature = "tracing")]
     fn warnings() {
@@ -1808,12 +1894,55 @@ mod test {
         assert_false("python_version == '3.9.0.*'");
         assert_true("python_version != '3.9.1'");
 
+        // Technically these is are valid substring comparisosn, but we do not allow them.
+        // e.g., using a version with patch components with `python_version` is considered
+        // impossible to satisfy since it is truncated at the minor version
+        assert_false("python_version in '3.9.0'");
+        // ... unless there are other versions that could match
+        assert_true("python_version in '3.* 3.9.0'");
+        // e.g., using a version that is not PEP 440 compliant is considered arbitrary
+        assert_true("python_version in 'foo'");
+
         assert_simplifies("python_version == '3.9'", "python_full_version == '3.9.*'");
         assert_simplifies(
             "python_version == '3.9.0'",
             "python_full_version == '3.9.*'",
         );
 
+        // `<version> in`
+        // e.g., when the range is not contiguous
+        assert_simplifies(
+            "python_version in '3.9 3.11'",
+            "python_full_version == '3.9.*' or python_full_version == '3.11.*'",
+        );
+        // e.g., when the range is contiguous
+        assert_simplifies(
+            "python_version in '3.9 3.10 3.11'",
+            "python_full_version >= '3.9' and python_full_version < '3.12'",
+        );
+        // e.g., with `implementation_version` instead of `python_version`
+        assert_simplifies(
+            "implementation_version in '3.9 3.11'",
+            "implementation_version == '3.9' or implementation_version == '3.11'",
+        );
+
+        // '<version> not in'
+        // e.g., when the range is not contiguous
+        assert_simplifies(
+            "python_version not in '3.9 3.11'",
+            "python_full_version < '3.9' or python_full_version == '3.10.*' or python_full_version >= '3.12'",
+        );
+        // e.g, when the range is contiguous
+        assert_simplifies(
+            "python_version not in '3.9 3.10 3.11'",
+            "python_full_version < '3.9' or python_full_version >= '3.12'",
+        );
+        // e.g., with `implementation_version` instead of `python_version`
+        assert_simplifies(
+            "implementation_version not in '3.9 3.11'",
+            "implementation_version != '3.9' and implementation_version != '3.11'",
+        );
+
         assert_simplifies("python_version != '3.9'", "python_full_version != '3.9.*'");
 
         assert_simplifies("python_version >= '3.9.0'", "python_full_version >= '3.9'");