Feature proposal: "-X exclusions-file" option for mconfig #14
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Packages can use this option to list symbols that shouldn't bring in the corresponding units. For example, Perl need not provide support for BSD index(3) as an alternative to C89 strchr(3), but "index" is the name of a Perl builtin, so that string in the source files is misunderstood by metaconfig as an attempt to use the BSD function. With this change, Perl can deal with this situation by adding "index" (and "rindex") to an exclusion list.
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Don't you think we also need to add support for the same -X in metaxref? Otherwise it would produce misleading output, listing symbols that metaconfig will ignore...
Can you please amend the pull-request to that effect?
I also spotted a minor omission: the usage help for metaconfig is not listing "-X file" (use lower-case). And the current convention is to align all options:
Usage: metaconfig .... [-X file]
....
-X: read symbol exclusions from file
Consistency is important :-)
I'm also wondering whether "packinit" should not be extended to have a "exclusion_file" variable pointing to a relative path under the top. That way, metaconfig could auto-pick the file. I'm really wondering, this is not rhetorical :-).
Because, of course, if you include that in the makefile, you can always say "make Configure" and list the exclusion file on the command line... I don't like things that are too magical and hidden. Yet I want comfort and error-prone / repeatable outcomes...
Anyway, thanks for this useful addition!
This usage has produced a depreaction warning since Perl 5.000, and was finally removed in Perl 5.22.
Otherwise, when mconfig is run with that option, the metaxref would confusingly refer to excluded symbols.
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Hi, Rafael. I've pushed some more commits making the changes you've asked for. I do like your suggestion of having the file named in Please let me know if you have any other concerns, or you'd like me to change anything else. |
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I see two minor points still :-)
In packinit.SH, you refer to "mconfig -X". The "mconfig" script is just an intermediate step, the real program that is installed is "metaconfig".
The usage for -X stipulates FILE and should be file, since the usage says [-X file]. Pesky review, I'm aware. :-D
Good work. Do you have time to fix these now, or do you prefer me to integrate now and let you submit another pull-request later?
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Nice catches :-) I've just pushed two more commits with tweaks for those — again, please let me know if you see anything else you'd like to be changed. |
In particular, this allows the -X option to be named in the .package file (which would have saved some confusion for Tux). This also reduces the amount of divergence from upstream dist, which goes a small way to addressing #43.
This branch pulls in some of the later changes from rmanfredi/dist#14. Raphaël suggested that the `.package` file be permitted to name the file used for the `-X` option, and that `packinit` prompt for it. Those changes have now been applied to our local copy of the (generated) `bin/mconfig` file, and I've regenerated our `.package` file with the relevant setting. Finally, our README no longer recommends the option, as it's no longer needed.
Packages can use this option to list symbols that shouldn't bring in the corresponding units. For example, Perl need not provide support for BSD index(3) as an alternative to C89 strchr(3), but "index" is the name of a Perl builtin, so that string in the source files is misunderstood by metaconfig as an attempt to use the BSD function.
With this change, Perl can deal with this situation by adding "index" (and "rindex") to an exclusion list.
Perl is already using a version of mconfig that includes this new feature:
Perl/metaconfig@c3a1ef2
Perl/perl5@92c878f
Please let me know what you think — thank you!