T16: on Windows a shell named without an extension means its .exe, and one with an extension keeps it; the resolver hands the session its program as UTF-8 text, so a program whose path is not UTF-8 never saves

src/term/shell.rs

@@ -78,11 +78,7 @@ pub fn launch(shell: &str, cwd: PathBuf, dir: &Path) -> anyhow::Result<Launch> {
         default_shell()?
     } else {
         // The settings checked this path; the session runs no other.
-        let found = crate::settings::program_path(shell)
-            .with_context(|| format!("shell integration: {shell:?} names no program"))?;
-        (found.to_str())
-            .with_context(|| format!("shell integration: {} is not UTF-8", found.display()))?
-            .to_string()
+        crate::settings::program_path(shell).context("shell integration")?
     };
     let name = Path::new(&path)
         .file_stem()

src/term/shell/tests.rs

@@ -251,6 +251,7 @@ fn powershell_reports_its_folder_byte_for_byte_and_keeps_the_status() {
 fn a_shell_named_bare_runs_from_its_full_path() {
     let started = launch("sh", PathBuf::from("/"), Path::new("/nonexistent")).expect("a launch");
     let (program, _) = started.program.expect("a program");
+    assert_eq!(program, crate::settings::program_path("sh").expect("sh"));
     assert!(Path::new(&program).is_absolute(), "{program}");
     assert!(launch("no-such-shell", PathBuf::from("/"), Path::new("/")).is_err());
 }