[m-rev.] for review: document workaround for bug #303

[Peter Wang]

On Fri, 22 Nov 2013 17:25:17 +1100 (EST), Julien Fischer <jfischer at opturion.com> wrote:
> 
> For review by anyone.
> 
> For the 13.05 release I intend to simply document this issue.  In the 
> longer term we should:
> 
> (1) not generate such enourmous Java class names

shorten_long_class_names tries to do this (the filename component
anyway) but could be more conservative.

> @@ -95,6 +95,23 @@ Java compiler, but we haven't tried that yet.
> 
>   -----------------------------------------------------------------------------
> 
> +BUILDING THE JAVA GRADE ON WINDOWS
> +
> +When building the Java grade on Windows it sometimes possible for the fully
> +qualified names of some generated files to exceed the maximum path length.
> +If this occurs the Mercury compiler will abort with a message like:
> +
> +   Uncaught Mercury exception:
> +   Software Error: parse_tree.module_cmds: predicate \
> +   `parse_tree.module_cmds.list_class_files_for_jar'/6: \
> +   Unexpected: io.file_type failed: No such file or directory
> +
> +In this case all that can (currently) be done is to reduce the length of the
> +build path, for example by shifting the build directory closer to the root of
> +the file system.

e.g. c:\m

Looks fine.

Peter