From be3faf0552d60c996aeb51016f93ef64a3dd2d6f Mon Sep 17 00:00:00 2001
From: Jonas Maier <jonas@x77.dev>
Date: Mon, 4 May 2026 23:57:57 +0200
Subject: escape test

---
 src/parse/mod.rs  | 22 +++++++++++--
 src/parse/test.rs | 98 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 117 insertions(+), 3 deletions(-)

diff --git a/src/parse/mod.rs b/src/parse/mod.rs
index 02012dc..efef937 100644
--- a/src/parse/mod.rs
+++ b/src/parse/mod.rs
@@ -717,12 +717,12 @@ impl StringDelimiter {
             let first = s[0];
             match self {
                 StringDelimiter::None => {
-                    if matches!(first, b' ' | b'$' | b'\\' | b'\'' | b'"') {
+                    if matches!(first, b' ' | b'$' | b'\\' | b'\'' | b'"' | b'|' | b'{' | b'}') {
                         out.push(b'\\');
                     }
                 }
                 StringDelimiter::Interp | StringDelimiter::InterpCustom(_) => {
-                    if matches!(first, b'$' | b'\\' | b'"') {
+                    if matches!(first, b'$' | b'\\' | b'"' | b'|') {
                         out.push(b'\\');
                     }
                 }
@@ -750,6 +750,22 @@ impl StringDelimiter {
         }
     }
 
+    pub fn write_opening_delimiter(&self, out: &mut BString) {
+        match self {
+            StringDelimiter::None => (),
+            StringDelimiter::Interp => out.push(b'"'),
+            StringDelimiter::Strict => out.push(b'\''),
+            StringDelimiter::InterpCustom(delim) => {
+                out.push_all(&delim);
+                out.push_all(b"\"\"\"");
+            }
+            StringDelimiter::StrictCustom(delim) => {
+                out.push_all(&delim);
+                out.push_all(b"'''");
+            }
+        }
+    }
+
     pub fn write_closing_delimiter(&self, out: &mut BString) {
         match self {
             StringDelimiter::None => (),
@@ -841,7 +857,7 @@ impl Parse for ExpString {
 
                 let x = b.adv();
 
-                if x == b'\\' {
+                if x == b'\\' && !delim.is_strict() {
                     if let Some(x) = parse_escape_code(b)? {
                         add_char(p, x);
                     }
diff --git a/src/parse/test.rs b/src/parse/test.rs
index dd6fbca..01dea5d 100644
--- a/src/parse/test.rs
+++ b/src/parse/test.rs
@@ -342,3 +342,101 @@ fn backslash_joins_lines() {
         pipes([cmd([estr(b"echo"), estr(b"foobar")]),])
     )
 }
+
+fn combinations(choices: &[&[u8]], n: usize) -> impl Iterator<Item = Vec<u8>> {
+    struct CombinationGenerator<'a> {
+        choices: &'a [&'a [u8]],
+        indices: Vec<usize>,
+        done: bool,
+    }
+
+    impl<'a> Iterator for CombinationGenerator<'a> {
+        type Item = Vec<u8>;
+
+        fn next(&mut self) -> Option<Self::Item> {
+            if self.done {
+                return None;
+            }
+
+            // Build current combination
+            let mut out = Vec::new();
+            for &i in &self.indices {
+                out.extend_from_slice(self.choices[i]);
+            }
+
+            // Increment like a base-N counter
+            for pos in (0..self.indices.len()).rev() {
+                if self.indices[pos] + 1 < self.choices.len() {
+                    self.indices[pos] += 1;
+                    for j in pos + 1..self.indices.len() {
+                        self.indices[j] = 0;
+                    }
+                    return Some(out);
+                }
+            }
+
+            // Last combination reached
+            self.done = true;
+            Some(out)
+        }
+    }
+
+    CombinationGenerator {
+        choices,
+        indices: vec![0; n],
+        done: n == 0 && choices.is_empty(),
+    }
+}
+
+fn coerce<T>(t: T) -> T {
+    t
+}
+
+#[test]
+fn test_escape_bruteforce() {
+    let words = [
+        coerce::<&'static [u8]>(b"\""),
+        b"'",
+        b"x",
+        b"y",
+        b"z",
+        b"\\",
+        b"|",
+        b"$",
+        b"{",
+        b"}",
+        b"'''",
+        b"\"\"\"",
+    ];
+
+    let quotes = [
+        StringDelimiter::None,
+        StringDelimiter::Interp,
+        StringDelimiter::Strict,
+        StringDelimiter::InterpCustom(b"x".into()),
+        StringDelimiter::StrictCustom(b"x".into()),
+    ];
+
+    for quote in quotes {
+        for phrase in combinations(&words[..], 5) {
+            let mut x = Vec::new();
+            quote.write_opening_delimiter(&mut x);
+            quote.escape(&phrase, &mut x);
+            quote.write_closing_delimiter(&mut x);
+            let s = ExpString::parse(&mut Cursor::new(&x, ParseMode::Command))
+                .map_err(|e| format!("{quote:?} escape {} failed: {e:?}", x.escape_ascii()))
+                .unwrap();
+            assert_eq!(s.parts.len(), 1, "{}", x.escape_ascii());
+            let s = s.parts[0].clone();
+            let s = s.unwrap_boring();
+
+            let x = String::from_utf8(x).unwrap();
+            let s = String::from_utf8(s).unwrap();
+            let phrase = String::from_utf8(phrase).unwrap();
+            assert_eq!(
+                phrase, s,
+                "escape/parse roundtrip in StringDelimiter::{quote:?} failed: {phrase} -> {x} -> {s}"
+            );
+        }
+    }
+}
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