From 59d0428eb5bfb5435eb8209ffb415ff0dfc68577 Mon Sep 17 00:00:00 2001
From: Radu Baston <65868820+radu2147@users.noreply.github.com>
Date: Sat, 25 Nov 2023 19:09:50 +0200
Subject: [PATCH] feat(linter): eslint 9.0 no empty static block (#1543)

Related [issue](https://github.com/oxc-project/oxc/issues/1191)

---------

Co-authored-by: Radu Baston <radu.baston@sectorlabs.ro>
---
 crates/oxc_linter/src/rules.rs                |  2 +
 .../src/rules/eslint/no_empty_static_block.rs | 76 +++++++++++++++++++
 .../src/snapshots/no_empty_static_block.snap  | 34 +++++++++
 3 files changed, 112 insertions(+)
 create mode 100644 crates/oxc_linter/src/rules/eslint/no_empty_static_block.rs
 create mode 100644 crates/oxc_linter/src/snapshots/no_empty_static_block.snap

diff --git a/crates/oxc_linter/src/rules.rs b/crates/oxc_linter/src/rules.rs
index 7750b5f7c..873f2a7ad 100644
--- a/crates/oxc_linter/src/rules.rs
+++ b/crates/oxc_linter/src/rules.rs
@@ -54,6 +54,7 @@ mod eslint {
     pub mod no_empty;
     pub mod no_empty_character_class;
     pub mod no_empty_pattern;
+    pub mod no_empty_static_block;
     pub mod no_eval;
     pub mod no_ex_assign;
     pub mod no_extra_boolean_cast;
@@ -249,6 +250,7 @@ oxc_macros::declare_all_lint_rules! {
     eslint::no_empty,
     eslint::no_empty_character_class,
     eslint::no_empty_pattern,
+    eslint::no_empty_static_block,
     eslint::no_eval,
     eslint::no_ex_assign,
     eslint::no_extra_boolean_cast,
diff --git a/crates/oxc_linter/src/rules/eslint/no_empty_static_block.rs b/crates/oxc_linter/src/rules/eslint/no_empty_static_block.rs
new file mode 100644
index 000000000..64ba4df03
--- /dev/null
+++ b/crates/oxc_linter/src/rules/eslint/no_empty_static_block.rs
@@ -0,0 +1,76 @@
+use oxc_ast::AstKind;
+use oxc_diagnostics::{
+    miette::{self, Diagnostic},
+    thiserror::Error,
+};
+use oxc_macros::declare_oxc_lint;
+use oxc_span::Span;
+
+use crate::{context::LintContext, rule::Rule, AstNode};
+
+#[derive(Debug, Error, Diagnostic)]
+#[error("eslint(no-empty-static-block): Disallow empty static blocks")]
+#[diagnostic(severity(warning), help("Unexpected empty static block."))]
+struct NoEmptyStaticBlockDiagnostic(#[label] pub Span);
+
+#[derive(Debug, Default, Clone)]
+pub struct NoEmptyStaticBlock;
+
+declare_oxc_lint!(
+    /// ### What it does
+    /// Disallows the usages of empty static blocks
+    ///
+    /// ### Why is this bad?
+    /// Empty block statements, while not technically errors, usually occur due to refactoring that wasn’t completed.
+    /// They can cause confusion when reading code.
+    ///
+    /// ### Example
+    /// ```javascript
+    ///
+    /// class Foo {
+    ///     static {
+    ///     }
+    /// }
+    ///
+    /// ```
+    NoEmptyStaticBlock,
+    suspicious
+);
+
+impl Rule for NoEmptyStaticBlock {
+    fn run<'a>(&self, node: &AstNode<'a>, ctx: &LintContext<'a>) {
+        if let AstKind::StaticBlock(static_block) = node.kind() {
+            if static_block.body.is_empty() {
+                if ctx.semantic().trivias().has_comments_between(static_block.span) {
+                    return;
+                }
+                ctx.diagnostic(NoEmptyStaticBlockDiagnostic(static_block.span));
+            }
+        }
+    }
+}
+
+#[test]
+fn test() {
+    use crate::tester::Tester;
+
+    let pass = vec![
+        "class Foo { static { bar(); } }",
+        "class Foo { static { /* comments */ } }",
+        "class Foo { static {
+			// comment
+			} }",
+        "class Foo { static { bar(); } static { bar(); } }",
+    ];
+
+    let fail = vec![
+        "class Foo { static {} }",
+        "class Foo { static { } }",
+        "class Foo { static {
+
+			 } }",
+        "class Foo { static { bar(); } static {} }",
+    ];
+
+    Tester::new_without_config(NoEmptyStaticBlock::NAME, pass, fail).test_and_snapshot();
+}
diff --git a/crates/oxc_linter/src/snapshots/no_empty_static_block.snap b/crates/oxc_linter/src/snapshots/no_empty_static_block.snap
new file mode 100644
index 000000000..e98d1afc7
--- /dev/null
+++ b/crates/oxc_linter/src/snapshots/no_empty_static_block.snap
@@ -0,0 +1,34 @@
+---
+source: crates/oxc_linter/src/tester.rs
+expression: no_empty_static_block
+---
+  ⚠ eslint(no-empty-static-block): Disallow empty static blocks
+   ╭─[no_empty_static_block.tsx:1:1]
+ 1 │ class Foo { static {} }
+   ·             ─────────
+   ╰────
+  help: Unexpected empty static block.
+
+  ⚠ eslint(no-empty-static-block): Disallow empty static blocks
+   ╭─[no_empty_static_block.tsx:1:1]
+ 1 │ class Foo { static { } }
+   ·             ──────────
+   ╰────
+  help: Unexpected empty static block.
+
+  ⚠ eslint(no-empty-static-block): Disallow empty static blocks
+   ╭─[no_empty_static_block.tsx:1:1]
+ 1 │ ╭─▶ class Foo { static {
+ 2 │ │   
+ 3 │ ╰─▶              } }
+   ╰────
+  help: Unexpected empty static block.
+
+  ⚠ eslint(no-empty-static-block): Disallow empty static blocks
+   ╭─[no_empty_static_block.tsx:1:1]
+ 1 │ class Foo { static { bar(); } static {} }
+   ·                               ─────────
+   ╰────
+  help: Unexpected empty static block.
+
+