Use new Shell::from_env method in clap_complete

Instead of having an fd specific implementation.

Cargo.lock

@@ -129,9 +129,9 @@ dependencies = [
 
 [[package]]
 name = "clap_complete"
-version = "4.0.3"
+version = "4.0.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dfe581a2035db4174cdbdc91265e1aba50f381577f0510d0ad36c7bc59cc84a3"
+checksum = "96b0fba905b035a30d25c1b585bf1171690712fbb0ad3ac47214963aa4acc36c"
 dependencies = [
  "clap",
 ]

Cargo.toml

@@ -50,7 +50,7 @@ normpath = "0.3.2"
 chrono = "0.4"
 once_cell = "1.15.0"
 crossbeam-channel = "0.5.6"
-clap_complete = {version = "4.0", optional = true}
+clap_complete = {version = "4.0.5", optional = true}
 
 [dependencies.clap]
 version = "4.0.12"

src/cli.rs

@@ -673,32 +673,12 @@ impl Opts {
         self.gen_completions
             .map(|maybe_shell| match maybe_shell {
                 Some(sh) => Ok(sh),
-                None => guess_shell(),
+                None => Shell::from_env().ok_or_else(|| anyhow!("Unable to get shell from environment")),
             })
             .transpose()
     }
 }
 
-#[cfg(feature = "completions")]
-fn guess_shell() -> anyhow::Result<Shell> {
-    let env_shell = std::env::var_os("SHELL").map(PathBuf::from);
-    if let Some(shell) = env_shell
-        .as_ref()
-        .and_then(|s| s.file_name())
-        .and_then(|s| s.to_str())
-    {
-        shell
-            .parse::<Shell>()
-            .map_err(|_| anyhow!("Unknown shell {}", shell))
-    } else {
-        // Assume powershell on windows
-        #[cfg(windows)]
-        return Ok(Shell::PowerShell);
-        #[cfg(not(windows))]
-        return Err(anyhow!("Unable to get shell from environment"));
-    }
-}
-
 #[derive(Copy, Clone, PartialEq, Eq, ValueEnum)]
 pub enum FileType {
     #[value(alias = "f")]