Content is not allowed in prolog

[basilevs]

When fetching repository from https://github.com/fabioz/Pydev/releases/download/pydev_10_1_3 P2 is redirected from

https://github.com/fabioz/Pydev/releases/download/pydev_10_1_3/content.jar

to

https://objects.githubusercontent.com/github-production-release-asset-2e65be/7935003/a5422aac-de32-40ef-a51c-5a186359ece6?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAIWNJYAX4CSVEH53A%2F20231019%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20231019T220152Z&X-Amz-Expires=300&X-Amz-Signature=7eb7ccbbd0c4871c6d3337de6de58be22466c44bf4276565a61f839659335df5&X-Amz-SignedHeaders=host&actor_id=0&key_id=0&repo_id=7935003&response-content-disposition=attachment%3B%20filename%3Dcontent.jar&response-content-type=application%2Foctet-stream

it is confused by the complexity of the resulting URL and fails to recognize content as JAR.

Please see eclipse-tycho/tycho#2938 for steps to reproduce.
Happens only in Tycho, PDE seems to work fine.

[basilevs]

I suspect the line

p2/bundles/org.eclipse.equinox.p2.metadata.repository/src/org/eclipse/equinox/internal/p2/metadata/repository/SimpleMetadataRepositoryFactory.java

Line 94 in 413c76a

if (localFile.getAbsolutePath().endsWith(JAR_EXTENSION)) {

is using wrong input to detect the JAR extension - localFile is mangled by injected CacheManager.

[merks]

It also works in the repository explorer

This suggests there is not p2 problem but rather a Tycho problem or a problem in how Tycho uses p2.

[laeubi]

This suggests there is not p2 problem but rather a Tycho problem or a problem in how Tycho uses p2.

Well the problem is that P2 assumes that a file that ends with .jar is a jar file and everything else is an xml file, what works for some but not all cases.

Since we have a buffered stream here, it would be better to look at the magic bytes what would be 50 4B in this case instead of rely on the name of a file.

[basilevs]

Indeed, modern Tycho customizes CacheManager and returns a File with a name that represents final redirect location. A fix on Tycho side could be to copy the from redirected name to original name.
However, SimpleMetadataRepositoryFactory should not rely on cache implementation and use storage location in internal logic. Such strong coupling makes injection of custom CacheManager too hard.

[basilevs]

Changed cache in Tycho master to return original file name.