Consider match-case stmts for C901, PLR0912, and PLR0915 (astra…

…l-sh#11521)

Resolves astral-sh#11421

## Summary

Instead of counting match/case as one statement, consider each `case` as
a conditional.

## Test Plan

`cargo test`

crates/ruff_linter/src/rules/mccabe/rules/function_is_too_complex.rs

@@ -96,8 +96,8 @@ fn get_complexity_number(stmts: &[Stmt]) -> usize {
                 complexity += get_complexity_number(orelse);
             }
             Stmt::Match(ast::StmtMatch { cases, .. }) => {
-                complexity += 1;
                 for case in cases {
+                    complexity += 1;
                     complexity += get_complexity_number(&case.body);
                 }
             }
@@ -429,4 +429,19 @@ def with_lock():
         assert_eq!(get_complexity_number(&stmts), 2);
         Ok(())
     }
+
+    #[test]
+    fn match_case() -> Result<()> {
+        let source = r"
+def f():
+    match a:
+        case 30:
+            print('foo')
+        case _:
+            print('bar')
+";
+        let stmts = parse_suite(source)?;
+        assert_eq!(get_complexity_number(&stmts), 3);
+        Ok(())
+    }
 }

crates/ruff_linter/src/rules/pylint/rules/too_many_branches.rs

@@ -176,10 +176,11 @@ fn num_branches(stmts: &[Stmt]) -> usize {
                         .sum::<usize>()
             }
             Stmt::Match(ast::StmtMatch { cases, .. }) => {
-                1 + cases
-                    .iter()
-                    .map(|case| num_branches(&case.body))
-                    .sum::<usize>()
+                cases.len()
+                    + cases
+                        .iter()
+                        .map(|case| num_branches(&case.body))
+                        .sum::<usize>()
             }
             // The `with` statement is not considered a branch but the statements inside the `with` should be counted.
             Stmt::With(ast::StmtWith { body, .. }) => num_branches(body),
@@ -278,6 +279,19 @@ else:
         Ok(())
     }
 
+    #[test]
+    fn match_case() -> Result<()> {
+        let source: &str = r"
+match x: # 2
+    case 0:
+        pass
+    case 1:
+        pass
+";
+        test_helper(source, 2)?;
+        Ok(())
+    }
+
     #[test]
     fn for_else() -> Result<()> {
         let source: &str = r"

crates/ruff_linter/src/rules/pylint/rules/too_many_statements.rs

@@ -90,6 +90,7 @@ fn num_statements(stmts: &[Stmt]) -> usize {
             Stmt::Match(ast::StmtMatch { cases, .. }) => {
                 count += 1;
                 for case in cases {
+                    count += 1;
                     count += num_statements(&case.body);
                 }
             }
@@ -233,6 +234,21 @@ def f():
         Ok(())
     }
 
+    #[test]
+    fn match_case() -> Result<()> {
+        let source: &str = r"
+def f():
+    match x:
+        case 3:
+            pass
+        case _:
+            pass
+";
+        let stmts = parse_suite(source)?;
+        assert_eq!(num_statements(&stmts), 6);
+        Ok(())
+    }
+
     #[test]
     fn many_statements() -> Result<()> {
         let source: &str = r"