Make Windows update find PowerShell hosts

src/bin/dosh-client.rs

@@ -4407,15 +4407,8 @@ fn latest_release_tag(repo: &str) -> Result<Option<String>> {
     }
     let latest_url = format!("{web}/releases/latest");
     let output = if cfg!(windows) {
-        Command::new("powershell.exe")
-            .arg("-NoProfile")
-            .arg("-ExecutionPolicy")
-            .arg("Bypass")
-            .arg("-Command")
-            .arg(windows_effective_url_script(&latest_url))
-            .stdin(Stdio::null())
-            .output()
-            .with_context(|| format!("resolve latest release for {web}"))?
+        let script = windows_effective_url_script(&latest_url);
+        windows_powershell_output(&script, &format!("resolve latest release for {web}"))?
     } else {
         Command::new("curl")
             .arg("-fsSL")
@@ -4449,17 +4442,8 @@ fn release_tag_download_url(repo: &str, tag: &str, artifact: &str) -> Option<Str
 
 fn url_reachable(url: &str) -> Result<bool> {
     let status = if cfg!(windows) {
-        Command::new("powershell.exe")
-            .arg("-NoProfile")
-            .arg("-ExecutionPolicy")
-            .arg("Bypass")
-            .arg("-Command")
-            .arg(windows_url_reachable_script(url))
-            .stdin(Stdio::null())
-            .stdout(Stdio::null())
-            .stderr(Stdio::null())
-            .status()
-            .with_context(|| format!("check {url}"))?
+        let script = windows_url_reachable_script(url);
+        windows_powershell_status(&script, &format!("check {url}"))?
     } else {
         Command::new("curl")
             .arg("-fsIL")
@@ -4591,15 +4575,7 @@ fn run_update_installer(
             binary_version,
         );
         let script = windows_deferred_update_script(std::process::id(), &script);
-        Command::new("powershell.exe")
-            .arg("-NoProfile")
-            .arg("-ExecutionPolicy")
-            .arg("Bypass")
-            .arg("-Command")
-            .arg(script)
-            .stdin(Stdio::null())
-            .spawn()
-            .context("start deferred dosh update installer")?;
+        windows_powershell_spawn(&script, "start deferred dosh update installer")?;
         println!("dosh update started; the installer will run after this process exits");
         return Ok(());
     }
@@ -4790,6 +4766,77 @@ fn windows_deferred_update_script(parent_pid: u32, installer_script: &str) -> St
     )
 }
 
+fn windows_powershell_command_candidates() -> &'static [&'static str] {
+    &["powershell.exe", "powershell", "pwsh.exe", "pwsh"]
+}
+
+fn windows_powershell_command(candidate: &str, script: &str) -> Command {
+    let mut command = Command::new(candidate);
+    command
+        .arg("-NoProfile")
+        .arg("-ExecutionPolicy")
+        .arg("Bypass")
+        .arg("-Command")
+        .arg(script)
+        .stdin(Stdio::null());
+    command
+}
+
+fn windows_powershell_output(script: &str, context: &str) -> Result<std::process::Output> {
+    let mut missing = Vec::new();
+    for candidate in windows_powershell_command_candidates() {
+        match windows_powershell_command(candidate, script).output() {
+            Ok(output) => return Ok(output),
+            Err(err) if err.kind() == std::io::ErrorKind::NotFound => {
+                missing.push(*candidate);
+            }
+            Err(err) => return Err(err).with_context(|| format!("{context} using {candidate}")),
+        }
+    }
+    Err(anyhow!(
+        "{context}: no PowerShell executable found; tried {}",
+        missing.join(", ")
+    ))
+}
+
+fn windows_powershell_status(script: &str, context: &str) -> Result<std::process::ExitStatus> {
+    let mut missing = Vec::new();
+    for candidate in windows_powershell_command_candidates() {
+        match windows_powershell_command(candidate, script)
+            .stdout(Stdio::null())
+            .stderr(Stdio::null())
+            .status()
+        {
+            Ok(status) => return Ok(status),
+            Err(err) if err.kind() == std::io::ErrorKind::NotFound => {
+                missing.push(*candidate);
+            }
+            Err(err) => return Err(err).with_context(|| format!("{context} using {candidate}")),
+        }
+    }
+    Err(anyhow!(
+        "{context}: no PowerShell executable found; tried {}",
+        missing.join(", ")
+    ))
+}
+
+fn windows_powershell_spawn(script: &str, context: &str) -> Result<Child> {
+    let mut missing = Vec::new();
+    for candidate in windows_powershell_command_candidates() {
+        match windows_powershell_command(candidate, script).spawn() {
+            Ok(child) => return Ok(child),
+            Err(err) if err.kind() == std::io::ErrorKind::NotFound => {
+                missing.push(*candidate);
+            }
+            Err(err) => return Err(err).with_context(|| format!("{context} using {candidate}")),
+        }
+    }
+    Err(anyhow!(
+        "{context}: no PowerShell executable found; tried {}",
+        missing.join(", ")
+    ))
+}
+
 fn powershell_string(value: &str) -> String {
     format!("'{}'", value.replace('\'', "''"))
 }
@@ -10588,8 +10635,9 @@ mod tests {
         update_binary_version_for_installer, update_installer_url, update_version_status,
         upsert_managed_block, valid_forward_host, vscode_command_candidates, vscode_safe_alias,
         wake_repaint_retry_deadline, windows_command_word, windows_deferred_update_script,
-        windows_effective_url_script, windows_mode_from_readonly, windows_readonly_from_mode,
-        windows_update_script, windows_url_reachable_script, windows_vt_output_mode,
+        windows_effective_url_script, windows_mode_from_readonly,
+        windows_powershell_command_candidates, windows_readonly_from_mode, windows_update_script,
+        windows_url_reachable_script, windows_vt_output_mode,
     };
     use dosh::config::{ClientConfig, CommandExtension, HostConfig};
     use dosh::native::EnvVar;
@@ -12978,6 +13026,14 @@ mod tests {
         assert!(!reachable.contains("curl"));
     }
 
+    #[test]
+    fn windows_update_tries_classic_and_core_powershell_hosts() {
+        assert_eq!(
+            windows_powershell_command_candidates(),
+            &["powershell.exe", "powershell", "pwsh.exe", "pwsh"]
+        );
+    }
+
     #[test]
     fn update_uses_local_tag_when_release_latest_is_older() {
         assert_eq!(