From 6f2f4e779671bbd26b2afc203210295e32f97f86 Mon Sep 17 00:00:00 2001
From: Jesse Luehrs <doy@tozt.net>
Date: Tue, 11 Jan 2022 01:16:17 -0500
Subject: move home directory expansion from cd to eval

---
 src/parse/ast.rs           | 49 +++++++++++++++++++++++++++++++++++++
 src/runner/builtins/mod.rs | 61 +++++++++-------------------------------------
 2 files changed, 60 insertions(+), 50 deletions(-)

diff --git a/src/parse/ast.rs b/src/parse/ast.rs
index 6a3ab8e..207a786 100644
--- a/src/parse/ast.rs
+++ b/src/parse/ast.rs
@@ -227,6 +227,9 @@ impl Word {
             let mut s = String::new();
             let mut pat = String::new();
             let mut is_glob = false;
+            let initial_bareword = word
+                .get(0)
+                .map_or(false, |part| matches!(part, WordPart::Bareword(_)));
             for part in word {
                 match part {
                     WordPart::Alternation(_) => unreachable!(),
@@ -247,6 +250,10 @@ impl Word {
                     }
                 }
             }
+            if initial_bareword {
+                s = expand_home(&s)?;
+                pat = expand_home(&pat)?;
+            }
             if is_glob {
                 let mut found = false;
                 for file in glob::glob_with(&pat, opts)? {
@@ -464,6 +471,48 @@ fn parse_fd(s: &str) -> std::os::unix::io::RawFd {
     }
 }
 
+fn expand_home(dir: &str) -> anyhow::Result<String> {
+    if dir.starts_with('~') {
+        let path: std::path::PathBuf = dir.into();
+        if let std::path::Component::Normal(prefix) =
+            path.components().next().unwrap()
+        {
+            let prefix_bytes = prefix.as_bytes();
+            let name = if prefix_bytes == b"~" {
+                None
+            } else {
+                Some(std::ffi::OsStr::from_bytes(&prefix_bytes[1..]))
+            };
+            if let Some(home) = home(name) {
+                Ok(home
+                    .join(path.strip_prefix(prefix).unwrap())
+                    .to_str()
+                    .unwrap()
+                    .to_string())
+            } else {
+                anyhow::bail!(
+                    "no such user: {}",
+                    name.map(std::ffi::OsStr::to_string_lossy)
+                        .as_ref()
+                        .unwrap_or(&std::borrow::Cow::Borrowed("(deleted)"))
+                );
+            }
+        } else {
+            unreachable!()
+        }
+    } else {
+        Ok(dir.to_string())
+    }
+}
+
+fn home(user: Option<&std::ffi::OsStr>) -> Option<std::path::PathBuf> {
+    let user = user.map_or_else(
+        || users::get_user_by_uid(users::get_current_uid()),
+        users::get_user_by_name,
+    );
+    user.map(|user| user.home_dir().to_path_buf())
+}
+
 #[cfg(test)]
 #[path = "test_ast.rs"]
 mod test;
diff --git a/src/runner/builtins/mod.rs b/src/runner/builtins/mod.rs
index 47d2f45..ff03499 100644
--- a/src/runner/builtins/mod.rs
+++ b/src/runner/builtins/mod.rs
@@ -60,55 +60,24 @@ fn cd(
 ) -> anyhow::Result<command::Child> {
     async fn async_cd(
         exe: crate::parse::Exe,
-        _env: &Env,
+        env: &Env,
         cfg: command::Cfg,
     ) -> std::process::ExitStatus {
-        let dir = exe.args().get(0).map_or("", String::as_str);
-        let dir = if dir.is_empty() {
-            if let Some(dir) = home(None) {
-                dir
-            } else {
-                bail!(cfg, exe, "couldn't find current user");
-            }
-        } else if dir.starts_with('~') {
-            let path: std::path::PathBuf = dir.into();
-            if let std::path::Component::Normal(prefix) =
-                path.components().next().unwrap()
-            {
-                let prefix_bytes = prefix.as_bytes();
-                let name = if prefix_bytes == b"~" {
-                    None
-                } else {
-                    Some(std::ffi::OsStr::from_bytes(&prefix_bytes[1..]))
-                };
-                if let Some(home) = home(name) {
-                    home.join(path.strip_prefix(prefix).unwrap())
-                } else {
-                    bail!(
-                        cfg,
-                        exe,
-                        "no such user: {}",
-                        name.map(std::ffi::OsStr::to_string_lossy)
-                            .as_ref()
-                            .unwrap_or(&std::borrow::Cow::Borrowed(
-                                "(deleted)"
-                            ))
-                    );
-                }
+        let dir = if let Some(dir) = exe.args().get(0) {
+            if dir.is_empty() {
+                ".".to_string()
             } else {
-                unreachable!()
+                dir.into()
             }
         } else {
-            dir.into()
+            let dir = env.var("HOME");
+            if dir.is_empty() {
+                bail!(cfg, exe, "could not find home directory");
+            }
+            dir
         };
         if let Err(e) = std::env::set_current_dir(&dir) {
-            bail!(
-                cfg,
-                exe,
-                "{}: {}",
-                crate::format::io_error(&e),
-                dir.display()
-            );
+            bail!(cfg, exe, "{}: {}", crate::format::io_error(&e), dir);
         }
         async_std::process::ExitStatus::from_raw(0)
     }
@@ -308,11 +277,3 @@ fn builtin(
     cfg.setup_command(&mut cmd);
     Ok(command::Child::new_wrapped(cmd.spawn(env)?))
 }
-
-fn home(user: Option<&std::ffi::OsStr>) -> Option<std::path::PathBuf> {
-    let user = user.map_or_else(
-        || users::get_user_by_uid(users::get_current_uid()),
-        users::get_user_by_name,
-    );
-    user.map(|user| user.home_dir().to_path_buf())
-}
-- 
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