From 23f9635d2cb523d63e5d1611dcf55922bcc54a87 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Donny/=EA=B0=95=EB=8F=99=EC=9C=A4?= <kdy1997.dev@gmail.com>
Date: Mon, 11 Mar 2024 15:52:57 +0900
Subject: [PATCH] fix(es/minifier): Do not evaluate `slice` calls with negative
 index (#8726)

**Related issue:**

 - Closes #8715.
---
 .../src/compress/pure/evaluate.rs             | 12 +++++
 .../tests/fixture/issues/8715/config.json     | 47 +++++++++++++++++++
 .../tests/fixture/issues/8715/input.js        |  2 +
 .../tests/fixture/issues/8715/output.js       |  9 ++++
 4 files changed, 70 insertions(+)
 create mode 100644 crates/swc_ecma_minifier/tests/fixture/issues/8715/config.json
 create mode 100644 crates/swc_ecma_minifier/tests/fixture/issues/8715/input.js
 create mode 100644 crates/swc_ecma_minifier/tests/fixture/issues/8715/output.js

diff --git a/crates/swc_ecma_minifier/src/compress/pure/evaluate.rs b/crates/swc_ecma_minifier/src/compress/pure/evaluate.rs
index cd2ac1aea26d..1c29a585a298 100644
--- a/crates/swc_ecma_minifier/src/compress/pure/evaluate.rs
+++ b/crates/swc_ecma_minifier/src/compress/pure/evaluate.rs
@@ -76,6 +76,10 @@ impl Pure<'_> {
                         if let Value::Known(start) =
                             call.args[0].expr.as_pure_number(&self.expr_ctx)
                         {
+                            if start.is_sign_negative() {
+                                return;
+                            }
+
                             let start = start.floor() as usize;
 
                             self.changed = true;
@@ -98,9 +102,17 @@ impl Pure<'_> {
                         let start = call.args[0].expr.as_pure_number(&self.expr_ctx);
                         let end = call.args[1].expr.as_pure_number(&self.expr_ctx);
                         if let Value::Known(start) = start {
+                            if start.is_sign_negative() {
+                                return;
+                            }
+
                             let start = start.floor() as usize;
 
                             if let Value::Known(end) = end {
+                                if end.is_sign_negative() {
+                                    return;
+                                }
+
                                 let end = end.floor() as usize;
                                 let end = end.min(arr.elems.len());
 
diff --git a/crates/swc_ecma_minifier/tests/fixture/issues/8715/config.json b/crates/swc_ecma_minifier/tests/fixture/issues/8715/config.json
new file mode 100644
index 000000000000..7e144b291fa7
--- /dev/null
+++ b/crates/swc_ecma_minifier/tests/fixture/issues/8715/config.json
@@ -0,0 +1,47 @@
+{
+    "defaults": true,
+    "arguments": false,
+    "arrows": true,
+    "booleans": true,
+    "booleans_as_integers": false,
+    "collapse_vars": true,
+    "comparisons": true,
+    "computed_props": true,
+    "conditionals": true,
+    "dead_code": true,
+    "directives": true,
+    "drop_console": false,
+    "drop_debugger": true,
+    "evaluate": true,
+    "expression": false,
+    "hoist_funs": false,
+    "hoist_props": true,
+    "hoist_vars": false,
+    "if_return": true,
+    "join_vars": true,
+    "keep_classnames": false,
+    "keep_fargs": true,
+    "keep_fnames": false,
+    "keep_infinity": false,
+    "loops": true,
+    "negate_iife": true,
+    "properties": true,
+    "reduce_funcs": false,
+    "reduce_vars": false,
+    "side_effects": true,
+    "switches": true,
+    "typeofs": true,
+    "unsafe": false,
+    "unsafe_arrows": false,
+    "unsafe_comps": false,
+    "unsafe_Function": false,
+    "unsafe_math": false,
+    "unsafe_symbols": false,
+    "unsafe_methods": false,
+    "unsafe_proto": false,
+    "unsafe_regexp": false,
+    "unsafe_undefined": false,
+    "unused": true,
+    "const_to_let": true,
+    "pristine_globals": true
+}
diff --git a/crates/swc_ecma_minifier/tests/fixture/issues/8715/input.js b/crates/swc_ecma_minifier/tests/fixture/issues/8715/input.js
new file mode 100644
index 000000000000..60fd274a2540
--- /dev/null
+++ b/crates/swc_ecma_minifier/tests/fixture/issues/8715/input.js
@@ -0,0 +1,2 @@
+console.log([1, 2, 3].slice(-1))
+console.log([1, 2, 3].slice(-1, 0))
diff --git a/crates/swc_ecma_minifier/tests/fixture/issues/8715/output.js b/crates/swc_ecma_minifier/tests/fixture/issues/8715/output.js
new file mode 100644
index 000000000000..823840bb3e2c
--- /dev/null
+++ b/crates/swc_ecma_minifier/tests/fixture/issues/8715/output.js
@@ -0,0 +1,9 @@
+console.log([
+    1,
+    2,
+    3
+].slice(-1)), console.log([
+    1,
+    2,
+    3
+].slice(-1, 0));