fix(venv): make relocatable activation scripts support ksh (#5640)

It transpires that detecting the directory a script was sourced from is
non-trivial across `bash`, `ksh` and `zsh`.

The previous version was a one-liner and supported `bash` and `zsh` but
not `ksh`.

It is possible to keep the one-liner and add `ksh` support, but that is
mutually-exclusive with `zsh`.

Therefore, the only way to square this circle is to add an `if` block. A
silver lining here is that although longer, the script is probably
easier to follow as there is less code-golfing going on.

crates/uv-shell/src/lib.rs

@@ -21,6 +21,8 @@ pub enum Shell {
     Nushell,
     /// C SHell (csh)
     Csh,
+    /// Korn SHell (ksh)
+    Ksh,
 }
 
 impl Shell {
@@ -43,6 +45,8 @@ impl Shell {
             Some(Shell::Bash)
         } else if std::env::var_os("ZSH_VERSION").is_some() {
             Some(Shell::Zsh)
+        } else if std::env::var_os("KSH_VERSION").is_some() {
+            Some(Shell::Ksh)
         } else if let Some(env_shell) = std::env::var_os("SHELL") {
             Shell::from_shell_path(env_shell)
         } else if cfg!(windows) {
@@ -99,6 +103,10 @@ impl Shell {
                     home_dir.join(".bashrc"),
                 ]
             }
+            Shell::Ksh => {
+                // On Ksh it's standard POSIX `.profile` for login shells, and `.kshrc` for non-login.
+                vec![home_dir.join(".profile"), home_dir.join(".kshrc")]
+            }
             Shell::Zsh => {
                 // On Zsh, we only need to update `.zshenv`. This file is sourced for both login and
                 // non-login shells. However, we match rustup's logic for determining _which_
@@ -174,7 +182,7 @@ impl Shell {
     pub fn prepend_path(self, path: &Path) -> Option<String> {
         match self {
             Shell::Nushell => None,
-            Shell::Bash | Shell::Zsh => Some(format!(
+            Shell::Bash | Shell::Zsh | Shell::Ksh => Some(format!(
                 "export PATH=\"{}:$PATH\"",
                 backslash_escape(&path.simplified_display().to_string()),
             )),
@@ -208,6 +216,7 @@ impl std::fmt::Display for Shell {
             Shell::Zsh => write!(f, "Zsh"),
             Shell::Nushell => write!(f, "Nushell"),
             Shell::Csh => write!(f, "Csh"),
+            Shell::Ksh => write!(f, "Ksh"),
         }
     }
 }
@@ -220,6 +229,7 @@ fn parse_shell_from_path(path: &Path) -> Option<Shell> {
         "zsh" => Some(Shell::Zsh),
         "fish" => Some(Shell::Fish),
         "csh" => Some(Shell::Csh),
+        "ksh" => Some(Shell::Ksh),
         "powershell" | "powershell_ise" => Some(Shell::Powershell),
         _ => None,
     }

crates/uv-virtualenv/src/activator/activate

@@ -22,10 +22,18 @@
 # This file must be used with "source bin/activate" *from bash*
 # you cannot run it directly
 
-
-if [ "${BASH_SOURCE-}" = "$0" ]; then
-    echo "You must source this script: \$ source $0" >&2
-    exit 33
+# Get script path (only used if environment is relocatable).
+if [ -n "${BASH_VERSION:+x}" ] ; then
+    SCRIPT_PATH="${BASH_SOURCE[0]}"
+    if [ "$SCRIPT_PATH" = "$0" ]; then
+        # Only bash has a reasonably robust check for source'dness.
+        echo "You must source this script: \$ source $0" >&2
+        exit 33
+    fi
+elif [ -n "${ZSH_VERSION:+x}" ] ; then
+    SCRIPT_PATH="${(%):-%x}"
+elif [ -n "${KSH_VERSION:+x}" ] ; then
+    SCRIPT_PATH="${.sh.file}"
 fi
 
 deactivate () {

crates/uv-virtualenv/src/virtualenv.rs

@@ -298,7 +298,7 @@ pub(crate) fn create(
             (true, "activate") => {
                 // Extremely verbose, but should cover all major POSIX shells,
                 // as well as platforms where `readlink` does not implement `-f`.
-                r#"'"$(dirname -- "$(CDPATH= cd -- "$(dirname -- ${BASH_SOURCE[0]:-${(%):-%x}})" && echo "$PWD")")"'"#
+                r#"'"$(dirname -- "$(CDPATH= cd -- "$(dirname -- "$SCRIPT_PATH")" > /dev/null && echo "$PWD")")"'"#
             }
             (true, "activate.bat") => r"%~dp0..",
             (true, "activate.fish") => {

crates/uv/src/commands/venv.rs

@@ -331,7 +331,7 @@ async fn venv_impl(
     // Determine the appropriate activation command.
     let activation = match Shell::from_env() {
         None => None,
-        Some(Shell::Bash | Shell::Zsh) => Some(format!(
+        Some(Shell::Bash | Shell::Zsh | Shell::Ksh) => Some(format!(
             "source {}",
             shlex_posix(venv.scripts().join("activate"))
         )),

crates/uv/tests/venv.rs

@@ -794,7 +794,7 @@ fn verify_pyvenv_cfg_relocatable() {
 
     let activate_sh = scripts.child("activate");
     activate_sh.assert(predicates::path::is_file());
-    activate_sh.assert(predicates::str::contains(r#"VIRTUAL_ENV=''"$(dirname -- "$(CDPATH= cd -- "$(dirname -- ${BASH_SOURCE[0]:-${(%):-%x}})" && echo "$PWD")")"''"#));
+    activate_sh.assert(predicates::str::contains(r#"VIRTUAL_ENV=''"$(dirname -- "$(CDPATH= cd -- "$(dirname -- "$SCRIPT_PATH")" > /dev/null && echo "$PWD")")"''"#));
 
     let activate_bat = scripts.child("activate.bat");
     activate_bat.assert(predicates::path::is_file());