fix(expansion): match ?, multi-star and lone * in ${x#pat} and ${x%pat}

crates/bashkit/src/interpreter/expansion.rs

@@ -1836,25 +1836,31 @@ impl Interpreter {
             return value.to_string();
         }
 
-        // Use glob_match for patterns with bracket expressions or extglob
-        if Self::has_unescaped_char(pattern, '[') || self.contains_unescaped_extglob(pattern) {
+        // A lone `*` matches the empty string (shortest) or everything
+        // (longest), on either side: `${x#*}` and `${x%*}` keep `x` whole.
+        if pattern == "*" {
+            return if longest {
+                String::new()
+            } else {
+                value.to_string()
+            };
+        }
+
+        // The literal fast paths below handle one `*`. Anything else (`?`,
+        // brackets, extglob, several stars) goes through glob_match.
+        if Self::has_unescaped_char(pattern, '[')
+            || Self::has_unescaped_char(pattern, '?')
+            || self.contains_unescaped_extglob(pattern)
+            || Self::find_unescaped_char(pattern, '*')
+                .is_some_and(|star| Self::find_unescaped_char(&pattern[star + 1..], '*').is_some())
+        {
             return self.remove_pattern_glob(value, pattern, prefix, longest);
         }
 
         let literal_pattern = Self::unescape_pattern_literal(pattern);
 
         if prefix {
             // Remove from beginning
-            if pattern == "*" {
-                if longest {
-                    return String::new();
-                } else if !value.is_empty() {
-                    return value.chars().skip(1).collect();
-                } else {
-                    return value.to_string();
-                }
-            }
-
             // Check if pattern contains *
             if let Some(star_pos) = Self::find_unescaped_char(pattern, '*') {
                 let prefix_part = &pattern[..star_pos];
@@ -1901,18 +1907,6 @@ impl Interpreter {
             }
         } else {
             // Remove from end (suffix)
-            if pattern == "*" {
-                if longest {
-                    return String::new();
-                } else if !value.is_empty() {
-                    let mut s = value.to_string();
-                    s.pop();
-                    return s;
-                } else {
-                    return value.to_string();
-                }
-            }
-
             // Check if pattern contains *
             if let Some(star_pos) = Self::find_unescaped_char(pattern, '*') {
                 let prefix_part = &pattern[..star_pos];

crates/bashkit/tests/spec_cases/bash/remove-pattern-glob.test.sh

@@ -0,0 +1,31 @@
+# ${x#pat} / ${x%pat} match the full glob grammar: a lone `*` matches the
+# empty string for the shortest forms, `?` matches one character, and several
+# `*` combine.
+
+### remove_lone_star
+x=abc; e=
+echo "${x#*}|${x%*}|${x##*}|${x%%*}|[${e#*}]"
+### expect
+abc|abc|||[]
+### end
+
+### remove_question_mark
+x=abc
+echo "${x#?}|${x%?}|${x#*?}|${x%?*}|${x##?}|${x#??}"
+### expect
+bc|ab|bc|ab|bc|c
+### end
+
+### remove_multi_star
+p=/a/b.c/d.tar.gz
+echo "${p#*/*/}|${p##*.*.}|${p%/*/*}|${p#/?/}|${p%%.*}|${p##*/}"
+### expect
+b.c/d.tar.gz|gz|/a|b.c/d.tar.gz|/a/b|d.tar.gz
+### end
+
+### remove_star_from_variable
+y='a*b'; q='*'
+echo "${y#$q}|${y#"$q"}|${y%$q}"
+### expect
+a*b|a*b|a*b
+### end

knowledge/log.md

@@ -2,6 +2,7 @@
 
 ## 2026-10-07
 
+* **Fix**: `${x#pat}`/`${x%pat}` follow the glob grammar. A lone `*` matches empty for the short forms (`${x#*}` and `${x%*}` keep `x`; they dropped a character), and patterns with `?` or several `*` (`${x%?}`, `${p#*/*/}`, `${p##*.*.}`) now match instead of being compared as literal text. Single-`*` patterns keep their linear fast path.
 * **Fix**: Quoted or escaped glob characters are literal everywhere. `echo a\*`, `a"*"` and `a'?'` no longer glob; `case`/`[[ == ]]` patterns match `"$x"`, `'a*'`, `a\*` and `\[s\]` literally; `"*"zz*` with no match prints `*zz*` (escapes no longer leak); `"$x"zz*` no longer reads `$xzz`; `'a'$x` expands and `'a'*` globs; `a{1,2}"*"` still brace-expands. The lexer escapes quoted glob characters in mixed words (the existing `QuotedGlobWord` convention, now with quote markers); `expand_word` returns unescaped text for non-glob uses; patterns use `expand_pattern_word`. Known gap: data from an unquoted expansion inside such a word loses `\` before glob characters when nothing matches.
 * **Fix**: A backslash outside quotes keeps `$` and `` ` `` literal. `echo \$HOME` printed the home directory; it now prints `$HOME`, as do `a\$x`, `\${x}` and `x=\$y` (the lexer emits the same NUL literal marker as quoted `"\$"`). Found while working gap telemetry.
 * **Fix**: `$'\x1e'` and `$'\x1f'` bytes (record/unit separators) are kept as data. They collided with the lexer's quote-boundary markers and were silently dropped, which broke the common `SEP=$'\x1f'` composite-key idiom for associative arrays (`v["$section"$'\x1f'"$key"]`). Decoded ANSI-C content now NUL-escapes those bytes like `$`. Found by gap telemetry (`config_ini_merge` replay printed nothing).