RFR: 8294549: configure script should detect unsupported path [v2]

[Mike Duigou]

On Mon, 7 Nov 2022 00:28:13 GMT, Mike Duigou <mduigou at openjdk.org> wrote:

>> The OpenJDK build system does not support building when the source code resides on a path that contains a space. This requirement is documented in the build instructions but not enforced by the configure script.
>> 
>> This change adds an explicit checks to the wrapper `configure` script that fail the build if the source code to be built is located in a directory who's path contains a space character or the build path cannot be determined.
>> 
>> Includes some idiom modernization and shell scripting best practices changes.
>
> Mike Duigou has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains one additional commit since the last revision:
> 
>   8294549: configure script should detect unsupported path
>   
>   The OpenJDK build system does not support building when the source code
>   resides on a path that contains a space. This requirement is documented in the
>   build instructions but not enforced by the configure script.
>   
>   This change adds an explicit checks to the wrapper `configure` script that fail
>   the build if the source code to be built is located in a directory who's path
>   contains a space character or the build path cannot be determined.

I have removed the path checking from the top level configure script but changes are still required in the `configure` wrapper to correctly pass a potentially bad path for the real configure script. I considered adding the path checking to `basic.m4` in `BASIC_SETUP_PATHS` but could not understand why `UTIL_FIXUP_PATH(TOPDIR)` doesn't already reject the bad path like it promises. (I was also reminded just how loathsome autoconf is as a language–all the worst parts of shell with even more cruft and weirdness).

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PR: https://git.openjdk.org/jdk/pull/10477