remove 'use-after-free'

src/main.zig

@@ -27,8 +27,11 @@ pub fn doRepl(allocator: *std.mem.Allocator, args_it: var) !void {
     const stdout = &stdout_file.outStream().stream;
     const scri_path = try (args_it.next(allocator) orelse @panic("expected scri path"));
 
-    var file_read = try std.fs.File.openRead(scri_path);
-    const total_bytes = try file_read.getEndPos();
+    var file_read_opt: ?std.fs.File = std.fs.File.openRead(scri_path) catch |err| blk: {
+        if (err == error.FileNotFound) break :blk null;
+        return err;
+    };
+    const total_bytes = if (file_read_opt) |file_read| try file_read.getEndPos() else 0;
 
     var cmds = langs.CommandList.init(allocator);
     defer cmds.deinit();
@@ -41,7 +44,7 @@ pub fn doRepl(allocator: *std.mem.Allocator, args_it: var) !void {
         // existing_cmds, and then passed along to cmds),
         // we can't defer them here
         var scri_existing = try allocator.alloc(u8, total_bytes);
-        _ = try file_read.read(scri_existing);
+        _ = try file_read_opt.?.read(scri_existing);
 
         // we can defer this because we copy the Command structs back to cmds
         var existing_cmds = try lang.parse(scri_existing);
@@ -64,7 +67,9 @@ pub fn doRepl(allocator: *std.mem.Allocator, args_it: var) !void {
         });
     }
 
+    if (file_read_opt) |file_read| {
         file_read.close();
+    }
 
     var file = try std.fs.File.openWrite(scri_path);
     defer file.close();
@@ -106,7 +111,7 @@ pub fn doRepl(allocator: *std.mem.Allocator, args_it: var) !void {
         var rd_line = readline.readline(c"> ");
         if (rd_line == null) break;
         readline.add_history(rd_line);
-        defer std.heap.c_allocator.destroy(rd_line);
+        //defer std.heap.c_allocator.destroy(rd_line);
 
         var line = rd_line[0..std.mem.len(u8, rd_line)];