From c3cf3792f36f7d827ebcce53d39298f44b852eee Mon Sep 17 00:00:00 2001
From: Johannes Altmanninger <aclopte@gmail.com>
Date: Sat, 20 Jul 2024 18:34:46 +0200
Subject: [PATCH] Expand tilde after brace expansion

Fixes #10610
---
 src/common.rs               | 7 ++++++-
 src/expand.rs               | 6 +++---
 tests/checks/expansion.fish | 7 +++++++
 3 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/src/common.rs b/src/common.rs
index ad10e3844..3500bf0e9 100644
--- a/src/common.rs
+++ b/src/common.rs
@@ -514,6 +514,7 @@ fn unescape_string_internal(input: &wstr, flags: UnescapeFlags) -> Option<WStrin
     // We only read braces as expanders if there's a variable expansion or "," in them.
     let mut vars_or_seps = vec![];
     let mut brace_count = 0;
+    let mut potential_word_start = None;
 
     let mut errored = false;
     #[derive(PartialEq, Eq)]
@@ -554,7 +555,9 @@ fn unescape_string_internal(input: &wstr, flags: UnescapeFlags) -> Option<WStrin
                     }
                 }
                 '~' => {
-                    if unescape_special && input_position == 0 {
+                    if unescape_special
+                        && (input_position == 0 || Some(input_position) == potential_word_start)
+                    {
                         to_append_or_none = Some(HOME_DIRECTORY);
                     }
                 }
@@ -605,6 +608,7 @@ fn unescape_string_internal(input: &wstr, flags: UnescapeFlags) -> Option<WStrin
                         to_append_or_none = Some(BRACE_BEGIN);
                         // We need to store where the brace *ends up* in the output.
                         braces.push(result.len());
+                        potential_word_start = Some(input_position + 1);
                     }
                 }
                 '}' => {
@@ -645,6 +649,7 @@ fn unescape_string_internal(input: &wstr, flags: UnescapeFlags) -> Option<WStrin
                     if unescape_special && brace_count > 0 {
                         to_append_or_none = Some(BRACE_SEP);
                         vars_or_seps.push(input_position);
+                        potential_word_start = Some(input_position + 1);
                     }
                 }
                 ' ' => {
diff --git a/src/expand.rs b/src/expand.rs
index 49b44f114..b54766f20 100644
--- a/src/expand.rs
+++ b/src/expand.rs
@@ -1130,7 +1130,9 @@ fn get_home_directory_name<'a>(input: &'a wstr, out_tail_idx: &mut usize) -> &'a
 
 /// Attempts tilde expansion of the string specified, modifying it in place.
 fn expand_home_directory(input: &mut WString, vars: &dyn Environment) {
-    if input.as_char_slice().first() != Some(&HOME_DIRECTORY) {
+    let starts_with_tilde = input.as_char_slice().first() == Some(&HOME_DIRECTORY);
+    *input = input.replace([HOME_DIRECTORY], L!("~"));
+    if !starts_with_tilde {
         return;
     }
 
@@ -1171,8 +1173,6 @@ fn expand_home_directory(input: &mut WString, vars: &dyn Environment) {
 
     if let Some(home) = home {
         input.replace_range(..tail_idx, &normalize_path(&home, true));
-    } else {
-        input.replace_range(0..1, L!("~"));
     }
 }
 
diff --git a/tests/checks/expansion.fish b/tests/checks/expansion.fish
index f646d1937..97546c53b 100644
--- a/tests/checks/expansion.fish
+++ b/tests/checks/expansion.fish
@@ -340,3 +340,10 @@ echo foo | $pager
 #CHECKERR: checks/expansion.fish (line 339): The expanded command is a keyword.
 #CHECKERR: echo foo | $pager
 #CHECKERR:            ^~~~~^
+
+echo {~,asdf}
+# CHECK: /{{.*}} asdf
+echo {asdf,~}
+# CHECK: asdf /{{.*}}
+echo {~}
+# CHECK: {~}