[Info-vax] PHP on VMS x86-64 9.2-2

[Stephen Hoffman]

On 2024-03-21 02:40:20 +0000, Lawrence D'Oliveiro said:

> On Wed, 20 Mar 2024 21:36:05 -0400, Arne Vajhøj wrote:
> 
>> On 3/20/2024 9:02 PM, Lawrence D'Oliveiro wrote:
>> 
>>> early days, it never progressed to developing library versioning.
>> 
>> It did.
> 
> It’s supposed to solve problems with linking with incompatible libraries.

Which is exactly what has happened here. An incompatible shareable 
image library was found in the default path, and its activation 
violated the rules the developers provided to the linker, and the 
activation was blocked.

As with myriad other implementation details, implementing 
upward-compatibility is complex and nuanced and interconnected, with 
the choices all having trade-offs.

Solutions range from static linking, to dynamic linking and shareable 
images on OpenVMS and GSMATCH, to a storage-intensive solution such as 
Nix as is used by NixOS and as available on some other platforms, to 
storage-intensive self-contained app bundles.

Adding to the complexity and nuance, various development projects can 
be fond of making incompatible changes whether for technical reasons or 
for expediency or whatever (q.v. The CADT Model, etc), as anyone 
familiar with Linux or OpenSSL or other platforms and packages will 
become well aware. These incompatibilities can arise at API, or ABI, or 
both. OpenVMS has had a few of these breaking changes too, not the 
least of which was with the BACKUP callable API. Which AFAIK never 
really has been fully cleaned up, either.

In the last couple of decades, OpenVMS has gone out of its way to 
effectively disable GSMATCH usage in certain of its own libraries. This 
being a workaround for a mess which arises from weak tooling, and from 
update practices that range from exceedingly cautious to just bad.

And as for API and ABI design consistency goals more generally, not 
breaking compatibility that needs to be broken "for reasons" is 
empirically a poor long-term strategy for success, too.




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