From d581183cc6afea171dde2a851d6b5c742b2179a7 Mon Sep 17 00:00:00 2001
From: KtorZ <matthias.benkort@gmail.com>
Date: Sat, 9 Mar 2024 18:59:35 +0100
Subject: [PATCH] Fix formatter discarding nul bytes.

---
 CHANGELOG.md                                         |  3 ++-
 crates/aiken-lang/src/format.rs                      |  1 +
 crates/aiken-lang/src/tests/format.rs                | 12 ++++++++++++
 .../src/tests/snapshots/format_nul_byte.snap         |  9 +++++++++
 4 files changed, 24 insertions(+), 1 deletion(-)
 create mode 100644 crates/aiken-lang/src/tests/snapshots/format_nul_byte.snap

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 03c1ce44..8a710e10 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -16,6 +16,7 @@
 - **aikup**: error message when version is not found. @rvcas
 - **aiken**: support outputting mainnet addresses for validators. @rvcas
 - **aiken-lang**: added serde to CheckedModule to encode modules as cbor. @rvcas
+- **aiken-lang**: Strings can contain a nul byte using the escape sequence `\0`. @KtorZ
 
 ### Fixed
 
@@ -32,7 +33,7 @@
 - **aiken-lang**: disallow `MLResult` in a type definition. @rvcas
 - **aiken-lang**: reversed deserialization of bls types out of data types. @rvcas
 - **aiken-lang**: validator args unexpectedly unbound causing code gen crashes. @rvcas
-- **aiken-lang**: allow implicitly discarded values when right-hand-side unified with `Void`. @KtorZ
+- **aiken-lang**: allow implicitly discarded values when right-hand side unified with `Void`. @KtorZ
 
 ### Changed
 
diff --git a/crates/aiken-lang/src/format.rs b/crates/aiken-lang/src/format.rs
index 25caf3ec..8d0d8ad6 100644
--- a/crates/aiken-lang/src/format.rs
+++ b/crates/aiken-lang/src/format.rs
@@ -2138,6 +2138,7 @@ fn escape(string: &str) -> String {
             '\n' => vec!['\\', 'n'],
             '\r' => vec!['\\', 'r'],
             '\t' => vec!['\\', 't'],
+            '\0' => vec!['\\', '0'],
             '"' => vec!['\\', c],
             '\\' => vec!['\\', c],
             _ => vec![c],
diff --git a/crates/aiken-lang/src/tests/format.rs b/crates/aiken-lang/src/tests/format.rs
index d04dfc30..a26eb58b 100644
--- a/crates/aiken-lang/src/tests/format.rs
+++ b/crates/aiken-lang/src/tests/format.rs
@@ -20,6 +20,18 @@ fn format_simple_module() {
     );
 }
 
+#[test]
+fn format_nul_byte() {
+    assert_format!(
+        r#"
+        fn label(str: String) -> Void {
+          str
+            |> builtin.append_string(@"\0", _)
+            |> builtin.debug(Void)
+        }"#
+    );
+}
+
 #[test]
 fn format_g1_element_constant() {
     assert_format!(
diff --git a/crates/aiken-lang/src/tests/snapshots/format_nul_byte.snap b/crates/aiken-lang/src/tests/snapshots/format_nul_byte.snap
new file mode 100644
index 00000000..b2b84286
--- /dev/null
+++ b/crates/aiken-lang/src/tests/snapshots/format_nul_byte.snap
@@ -0,0 +1,9 @@
+---
+source: crates/aiken-lang/src/tests/format.rs
+description: "Code:\n\nfn label(str: String) -> Void {\n  str\n    |> builtin.append_string(@\"\\0\", _)\n    |> builtin.debug(Void)\n}"
+---
+fn label(str: String) -> Void {
+  str
+    |> builtin.append_string(@"\0", _)
+    |> builtin.debug(Void)
+}