I'm not sure which version of regexp the Maven build is pulling down; will 
check.

--
   /_  Joe Kesselman (he/him/his)
-/ _) My Alexa skill for New Music/New Sounds fans:
   /   https://www.amazon.com/dp/B09WJ3H657/

Caveat: Opinionated old geezer with overcompensated writer's block. May be 
redundant, verbose, prolix, sesquipedalian, didactic, officious, or redundant.
________________________________
From: Jared Davis <jar...@davisprogramming.com>
Sent: Friday, March 29, 2024 11:44:34 AM
To: dev@xalan.apache.org <dev@xalan.apache.org>
Subject: Re: Embedded packages, architectural decision needed

The 1.3 version of regexp is known to be buggy. Old email thread  "Source of 
regular expression jar in Xalan 2.7.3 RC9" Jan - April 2023 suggests removing 
it.



<https://github.com/apache/xalan-java/blob/master/xalan/pom.xml>
[xalan-java.png]
xalan-java/xalan/pom.xml at master · 
apache/xalan-java<https://github.com/apache/xalan-java/blob/master/xalan/pom.xml>
github.com<https://github.com/apache/xalan-java/blob/master/xalan/pom.xml>


    <dependency>
      <groupId>regexp</groupId>
      <artifactId>regexp</artifactId>
      <version>1.3</version>
    </dependency>


<https://jakarta.apache.org/regexp/changes.html>
Jakarta Regexp - Jakarta Regexp History of 
Changes<https://jakarta.apache.org/regexp/changes.html>
jakarta.apache.org<https://jakarta.apache.org/regexp/changes.html>
[favicon.ico]<https://jakarta.apache.org/regexp/changes.html>

1.4 from aug 2005 has a critical fix


  *   Fixed Bug 2121<http://issues.apache.org/bugzilla/show_bug.cgi?id=2121>: 
'.' or '-' in bracket expression gives unexpected results (VG)



On Mar 29, 2024, at 11:07 AM, Joseph Kessselman <kesh...@alum.mit.edu> wrote:

(See https://issues.apache.org/jira/browse/XALANJ-2436)

At the moment, Xalan -- even the Maven build -- is still importing bcel and 
regexp into its jarfiles without renaming/"shading" them.

While XALANJ-2436 expresses the problem in terms of Endorsed Classpath (which 
is no longer needed since Sun shaded their copy of Xalan and the 
javax/JAXP/TrAX interfaces select between implementations via a properties 
setting), it is potentially a general issue. With this setup, if there are 
conflicting implementations available, it may be impossible for a user to 
select both the desired version of Xalan and the desired version of these 
dependencies.


There are only a few clean solutions. Simplest first:

#1) Make these packages external dependencies for Xalan, as are so many other 
packages. Advantage: Free ability to mix and match versions. Disadvantage: It's 
possible to run into incompatibilities as packages are independently upgraded. 
The various version-dependency systems are *supposed* to be able to manage 
this, but don't always.

#2) Shade these packages, renaming Xalan's copy of them (exactly as Sun shades 
Xalan itself to avoid having their possibly-outdated convenience copy conflict 
with ours). Advantage: Xalan always runs with a known version of these tools, 
and user doesn't have to supply them. Disadvantage: If user wants to override 
Xalan's use of that binding, they need to provide a new shaded copy of the 
library; merely putting the standard jarfile earlier on the classpath isn't 
sufficient.

#3) Have Xalan run in an independent classloader, OSGi-style. Advantage: 
Doesn't require renaming, but still isolates Xalan's choice of library version 
from that of the rest of the application. Also, opens the opportunity for OSGi 
demand-loading, which can significantly improve efficiency by not bringing in 
any classes not actually in use. Disadvantage: Complexity, potential user 
confusion when debugging, and major implementation effort to get the full 
benefit.

#Ugh) We *could* leave it as it is. I don't consider that a clean solution, but 
it is a solution. It's no worse than we have been, but no better... and given 
how many other external dependencies we have, I have trouble justifying these 
two being special cases worth embedding.


I think we need to make an architectural decision on this. As I say, I 
currently prefer #1. That *would* mean Xalan users would have to be aware of 
and provide these dependencies, which would be a change from past releases. But 
it's really not different from our dependencies upon Xerces or other external 
packages.

And I don't see a good reason to continue embedding without renaming; this 
feels like a tradition we should break.

--
` /_  Joe Kesselman (he/him/his)
-/ _) My Alexa skill for New Music/New Sounds fans:
 /   https://www.amazon.com/dp/B09WJ3H657/
Caveat: Opinionated old geezer with overcompensated writer's block. May be 
redundant, verbose, prolix, sesquipedalian, didactic, officious, or redundant. 
Feel free to call him on it.
<OpenPGP_0xFFBAFF963D937815.asc>

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