windows, @responsefile and warnings-as-errors

[vicuna]

Original bug ID: 5312
Reporter: Dmitry Grebeniuk
Assigned to: @gasche
Status: closed (set by @xavierleroy on 2016-12-07T10:49:17Z)
Resolution: fixed
Priority: normal
Severity: minor
Version: 3.12.1+dev
Target version: 4.00.0+dev
Category: ~DO NOT USE (was: OCaml general)
Related to: #6864
Monitored by: @ygrek

Bug description

I have software that uses new syntax of ocamlc command
line, "-w @A" (enable all warnings and treat them as
errors), but function "expand_argument" in
"byterun/win32.c" tries to expand "@A" as a filename:

ocaml -w @A
Cannot open file a

As the @responsefile functionality is not widely used
anymore, I have fixed it locally and have not
experienced any trouble. I don't know whether
this solution is acceptable.

[vicuna]

Comment author: @lefessan

Gabriel, we agreed that it is time to remove responsefile from the runtime. Could you do it ?

[vicuna]

Comment author: @damiendoligez

For the record, you can work around the problem by adding something before the @:

ocamlc -w a@a

[vicuna]

Comment author: @gasche

The feature has now been removed.

This means that OCaml programs will not expand command-line arguments beginning with a "@" as responsefiles on Windows anymore, but instead pass them directly to the program (in Sys.argv as usual). All OCaml programs compiled under Windows are affected.

This is a change of behavior, but a community poll on the mailing-list indicated that basically no one was aware of this feature. Removing it will therefore protect users from a few surprises if they try, as the OCaml compiler authors, to use "@..." as a valid syntax for specific command-line parameters...