From 822c67b3e0f86a89a1391b448dcce509baff7a6f Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <mitchell.hashimoto@gmail.com>
Date: Tue, 14 Nov 2023 16:58:27 -0800
Subject: [PATCH] termio/exec: fall back to default command if specified
 command not found

Fixes #880

If a command is specified but it can't be found, then we try to fallback
to a default command like "sh" and log the issue. This prevents Ghostty
from simply exiting.
---
 src/termio/Exec.zig | 25 ++++++++++++++++++++-----
 1 file changed, 20 insertions(+), 5 deletions(-)

diff --git a/src/termio/Exec.zig b/src/termio/Exec.zig
index 85513ba91..fa85c53d4 100644
--- a/src/termio/Exec.zig
+++ b/src/termio/Exec.zig
@@ -722,13 +722,28 @@ const Subprocess = struct {
         const alloc = arena.allocator();
 
         // Determine the path to the binary we're executing
+        const default_path = switch (builtin.os.tag) {
+            .windows => "cmd.exe",
+            else => "sh",
+        };
         const path = try Command.expandPath(
             alloc,
-            opts.full_config.command orelse switch (builtin.os.tag) {
-                .windows => "cmd.exe",
-                else => "sh",
-            },
-        ) orelse return error.CommandNotFound;
+            opts.full_config.command orelse default_path,
+        ) orelse path: {
+            // If we had a command specified, try to at least fall
+            // back to a default value like "sh" so that Ghostty
+            // launches.
+            if (opts.full_config.command) |command| {
+                log.warn("unable to find command, fallbacking back to default command={s}", .{command});
+                if (try Command.expandPath(
+                    alloc,
+                    default_path,
+                )) |path| break :path path;
+            }
+
+            log.warn("unable to find default command to launch, exiting", .{});
+            return error.CommandNotFound;
+        };
 
         // On macOS, we launch the program as a login shell. This is a Mac-specific
         // behavior (see other terminals). Terminals in general should NOT be