Prefer itertools.pairwise() over zip() for successive pairs (RUF007) (#3501)

crates/ruff/resources/test/fixtures/ruff/RUF007.py

@@ -0,0 +1,19 @@
+input = [1, 2, 3]
+otherInput = [2, 3, 4]
+
+# OK
+zip(input, otherInput)  # different inputs
+zip(input, otherInput[1:])  # different inputs
+zip(input, input[2:])  # not successive
+zip(input[:-1], input[2:])  # not successive
+list(zip(input, otherInput))  # nested call
+zip(input, input[1::2])  # not successive
+
+# Errors
+zip(input, input[1:])
+zip(input, input[1::1])
+zip(input[:-1], input[1:])
+zip(input[1:], input[2:])
+zip(input[1:-1], input[2:])
+list(zip(input, input[1:]))
+list(zip(input[:-1], input[1:]))

crates/ruff/src/checkers/ast/mod.rs

@@ -2866,6 +2866,12 @@ where
                     flake8_pytest_style::rules::fail_call(self, func, args, keywords);
                 }
 
+                if self.settings.rules.enabled(Rule::PairwiseOverZipped) {
+                    if self.settings.target_version >= PythonVersion::Py310 {
+                        ruff::rules::pairwise_over_zipped(self, func, args);
+                    }
+                }
+
                 // flake8-simplify
                 if self
                     .settings

crates/ruff/src/codes.rs

@@ -661,6 +661,7 @@ pub fn code_to_rule(linter: Linter, code: &str) -> Option<Rule> {
         (Ruff, "003") => Rule::AmbiguousUnicodeCharacterComment,
         (Ruff, "005") => Rule::UnpackInsteadOfConcatenatingToCollectionLiteral,
         (Ruff, "006") => Rule::AsyncioDanglingTask,
+        (Ruff, "007") => Rule::PairwiseOverZipped,
         (Ruff, "100") => Rule::UnusedNOQA,
 
         // flake8-django

crates/ruff/src/registry.rs

@@ -602,6 +602,7 @@ ruff_macros::register_rules!(
     rules::ruff::rules::UnpackInsteadOfConcatenatingToCollectionLiteral,
     rules::ruff::rules::AsyncioDanglingTask,
     rules::ruff::rules::UnusedNOQA,
+    rules::ruff::rules::PairwiseOverZipped,
     // flake8-django
     rules::flake8_django::rules::NullableModelStringField,
     rules::flake8_django::rules::LocalsInRenderFunction,

crates/ruff/src/rules/ruff/mod.rs

@@ -142,4 +142,14 @@ mod tests {
         assert_yaml_snapshot!(diagnostics);
         Ok(())
     }
+
+    #[test]
+    fn ruff_pairwise_over_zipped() -> Result<()> {
+        let diagnostics = test_path(
+            Path::new("ruff/RUF007.py"),
+            &settings::Settings::for_rules(vec![Rule::PairwiseOverZipped]),
+        )?;
+        assert_yaml_snapshot!(diagnostics);
+        Ok(())
+    }
 }

crates/ruff/src/rules/ruff/rules/mod.rs

@@ -1,19 +1,21 @@
+mod ambiguous_unicode_character;
+mod asyncio_dangling_task;
+mod pairwise_over_zipped;
+mod unpack_instead_of_concatenating_to_collection_literal;
+mod unused_noqa;
+
 pub use ambiguous_unicode_character::{
     ambiguous_unicode_character, AmbiguousUnicodeCharacterComment,
     AmbiguousUnicodeCharacterDocstring, AmbiguousUnicodeCharacterString,
 };
 pub use asyncio_dangling_task::{asyncio_dangling_task, AsyncioDanglingTask};
+pub use pairwise_over_zipped::{pairwise_over_zipped, PairwiseOverZipped};
 pub use unpack_instead_of_concatenating_to_collection_literal::{
     unpack_instead_of_concatenating_to_collection_literal,
     UnpackInsteadOfConcatenatingToCollectionLiteral,
 };
 pub use unused_noqa::{UnusedCodes, UnusedNOQA};
 
-mod ambiguous_unicode_character;
-mod asyncio_dangling_task;
-mod unpack_instead_of_concatenating_to_collection_literal;
-mod unused_noqa;
-
 #[derive(Clone, Copy)]
 pub enum Context {
     String,

crates/ruff/src/rules/ruff/rules/pairwise_over_zipped.rs

@@ -0,0 +1,132 @@
+use num_traits::ToPrimitive;
+use rustpython_parser::ast::{Constant, Expr, ExprKind, Unaryop};
+
+use ruff_diagnostics::{Diagnostic, Violation};
+use ruff_macros::{derive_message_formats, violation};
+
+use crate::checkers::ast::Checker;
+use crate::Range;
+
+#[violation]
+pub struct PairwiseOverZipped;
+
+impl Violation for PairwiseOverZipped {
+    #[derive_message_formats]
+    fn message(&self) -> String {
+        format!("Prefer `itertools.pairwise()` over `zip()` when iterating over successive pairs")
+    }
+}
+
+#[derive(Debug)]
+struct SliceInfo {
+    arg_name: String,
+    slice_start: Option<i64>,
+}
+
+impl SliceInfo {
+    pub fn new(arg_name: String, slice_start: Option<i64>) -> Self {
+        Self {
+            arg_name,
+            slice_start,
+        }
+    }
+}
+
+/// Return the argument name, lower bound, and  upper bound for an expression, if it's a slice.
+fn match_slice_info(expr: &Expr) -> Option<SliceInfo> {
+    let ExprKind::Subscript { value, slice, .. } = &expr.node else {
+        return None;
+    };
+
+    let ExprKind::Name { id: arg_id, .. } = &value.node else {
+        return None;
+    };
+
+    let ExprKind::Slice { lower,  step, .. } = &slice.node else {
+        return None;
+    };
+
+    // Avoid false positives for slices with a step.
+    if let Some(step) = step {
+        if let Some(step) = to_bound(step) {
+            if step != 1 {
+                return None;
+            }
+        } else {
+            return None;
+        }
+    }
+
+    Some(SliceInfo::new(
+        arg_id.to_string(),
+        lower.as_ref().and_then(|expr| to_bound(expr)),
+    ))
+}
+
+fn to_bound(expr: &Expr) -> Option<i64> {
+    match &expr.node {
+        ExprKind::Constant {
+            value: Constant::Int(value),
+            ..
+        } => value.to_i64(),
+        ExprKind::UnaryOp {
+            op: Unaryop::USub | Unaryop::Invert,
+            operand,
+        } => {
+            if let ExprKind::Constant {
+                value: Constant::Int(value),
+                ..
+            } = &operand.node
+            {
+                value.to_i64().map(|v| -v)
+            } else {
+                None
+            }
+        }
+        _ => None,
+    }
+}
+
+/// RUF007
+pub fn pairwise_over_zipped(checker: &mut Checker, func: &Expr, args: &[Expr]) {
+    let ExprKind::Name { id, .. } = &func.node else {
+        return;
+    };
+
+    if !(args.len() > 1 && id == "zip" && checker.ctx.is_builtin(id)) {
+        return;
+    };
+
+    // Allow the first argument to be a `Name` or `Subscript`.
+    let Some(first_arg_info) = ({
+        if let ExprKind::Name { id, .. } = &args[0].node {
+            Some(SliceInfo::new(id.to_string(), None))
+        } else {
+            match_slice_info(&args[0])
+        }
+    }) else {
+        return;
+    };
+
+    // Require second argument to be a `Subscript`.
+    let ExprKind::Subscript { .. } = &args[1].node else {
+        return;
+    };
+    let Some(second_arg_info) = match_slice_info(&args[1]) else {
+        return;
+    };
+
+    // Verify that the arguments match the same name.
+    if first_arg_info.arg_name != second_arg_info.arg_name {
+        return;
+    }
+
+    // Verify that the arguments are successive.
+    if second_arg_info.slice_start.unwrap_or(0) - first_arg_info.slice_start.unwrap_or(0) != 1 {
+        return;
+    }
+
+    checker
+        .diagnostics
+        .push(Diagnostic::new(PairwiseOverZipped, Range::from(func)));
+}

crates/ruff/src/rules/ruff/snapshots/ruff__rules__ruff__tests__ruff_pairwise_over_zipped.snap

@@ -0,0 +1,96 @@
+---
+source: crates/ruff/src/rules/ruff/mod.rs
+expression: diagnostics
+---
+- kind:
+    name: PairwiseOverZipped
+    body: "Prefer `itertools.pairwise()` over `zip()` when iterating over successive pairs"
+    suggestion: ~
+    fixable: false
+  location:
+    row: 13
+    column: 0
+  end_location:
+    row: 13
+    column: 3
+  fix: ~
+  parent: ~
+- kind:
+    name: PairwiseOverZipped
+    body: "Prefer `itertools.pairwise()` over `zip()` when iterating over successive pairs"
+    suggestion: ~
+    fixable: false
+  location:
+    row: 14
+    column: 0
+  end_location:
+    row: 14
+    column: 3
+  fix: ~
+  parent: ~
+- kind:
+    name: PairwiseOverZipped
+    body: "Prefer `itertools.pairwise()` over `zip()` when iterating over successive pairs"
+    suggestion: ~
+    fixable: false
+  location:
+    row: 15
+    column: 0
+  end_location:
+    row: 15
+    column: 3
+  fix: ~
+  parent: ~
+- kind:
+    name: PairwiseOverZipped
+    body: "Prefer `itertools.pairwise()` over `zip()` when iterating over successive pairs"
+    suggestion: ~
+    fixable: false
+  location:
+    row: 16
+    column: 0
+  end_location:
+    row: 16
+    column: 3
+  fix: ~
+  parent: ~
+- kind:
+    name: PairwiseOverZipped
+    body: "Prefer `itertools.pairwise()` over `zip()` when iterating over successive pairs"
+    suggestion: ~
+    fixable: false
+  location:
+    row: 17
+    column: 0
+  end_location:
+    row: 17
+    column: 3
+  fix: ~
+  parent: ~
+- kind:
+    name: PairwiseOverZipped
+    body: "Prefer `itertools.pairwise()` over `zip()` when iterating over successive pairs"
+    suggestion: ~
+    fixable: false
+  location:
+    row: 18
+    column: 5
+  end_location:
+    row: 18
+    column: 8
+  fix: ~
+  parent: ~
+- kind:
+    name: PairwiseOverZipped
+    body: "Prefer `itertools.pairwise()` over `zip()` when iterating over successive pairs"
+    suggestion: ~
+    fixable: false
+  location:
+    row: 19
+    column: 5
+  end_location:
+    row: 19
+    column: 8
+  fix: ~
+  parent: ~
+

ruff.schema.json

@@ -2013,6 +2013,7 @@
         "RUF003",
         "RUF005",
         "RUF006",
+        "RUF007",
         "RUF1",
         "RUF10",
         "RUF100",