move tilde expansion functionality to os/homedir

src/config/Config.zig

@@ -4257,33 +4257,24 @@ pub const RepeatablePath = struct {
 
             // Check if the path starts with a tilde and expand it to the home directory on linux/mac
             if (std.mem.startsWith(u8, path, "~/")) {
-                const home_var = try internal_os.home(&buf); // cache this?
-                if (home_var) |home_dir| {
-                    const rest = path[1..]; // Skip the ~
-                    const expanded_len = home_dir.len + rest.len;
-                    if (expanded_len > buf.len) {
-                        try diags.append(alloc, .{
-                            .message = try std.fmt.allocPrintZ(
-                                alloc,
-                                "error resolving file path {s}: path too long after expanding home directory",
-                                .{path},
-                            ),
-                        });
-                        self.value.items[i] = .{ .required = "" };
-                        continue;
-                    }
-
-                    @memcpy(buf[home_dir.len..expanded_len], rest);
-
+                if (try internal_os.expandHome(path, &buf)) |expanded_path| {
                     log.debug(
                         "expanding file path from home directory: path={s}",
-                        .{buf[0..expanded_len]},
+                        .{expanded_path},
                     );
-
                     switch (self.value.items[i]) {
-                        .optional, .required => |*p| p.* = try alloc.dupeZ(u8, buf[0..expanded_len]),
+                        .optional, .required => |*p| p.* = try alloc.dupeZ(u8, expanded_path),
                     }
-
+                    continue;
+                } else {
+                    try diags.append(alloc, .{
+                        .message = try std.fmt.allocPrintZ(
+                            alloc,
+                            "error expanding home path {s}",
+                            .{path},
+                        ),
+                    });
+                    self.value.items[i] = .{ .required = "" };
                     continue;
                 }
             }

src/os/homedir.zig

@@ -110,6 +110,22 @@ fn trimSpace(input: []const u8) []const u8 {
     return std.mem.trim(u8, input, " \n\t");
 }
 
+/// Expands a path that starts with a tilde (~) to the home directory of the user.
+///
+/// Errors if `home` fails or if the size of the expanded path is larger than `buf.len`.
+///
+/// Returns null if the value returned from `home` is null, otherwise returns a slice to the expanded path.
+pub fn expandHome(path: []const u8, buf: []u8) !?[]u8 {
+    const home_dir = try home(buf) orelse return null;
+    const rest = path[1..]; // Skip the ~
+    const expanded_len = home_dir.len + rest.len;
+
+    if (expanded_len > buf.len) return Error.BufferTooSmall;
+    @memcpy(buf[home_dir.len..expanded_len], rest);
+
+    return buf[0..expanded_len];
+}
+
 test {
     const testing = std.testing;
 

src/os/main.zig

@@ -38,6 +38,7 @@ pub const freeTmpDir = file.freeTmpDir;
 pub const isFlatpak = flatpak.isFlatpak;
 pub const FlatpakHostCommand = flatpak.FlatpakHostCommand;
 pub const home = homedir.home;
+pub const expandHome = homedir.expandHome;
 pub const ensureLocale = locale.ensureLocale;
 pub const clickInterval = mouse.clickInterval;
 pub const open = openpkg.open;