RFR: 8321224: ct.sym for JDK 22 contains references to internal modules [v3]

[Jan Lahoda]

> As part of:
> https://github.com/openjdk/jdk/pull/16505
> 
> there are new symbol files for JDK 22, and @jddarcy noted the content looks weird.
> 
> I was investigating, and found a few problems, some introduced by https://github.com/openjdk/jdk/commit/fc314740e947b2338ab9e4d4fce0c4f52de56c4b, some pre-existing.
> 
> Note that https://github.com/openjdk/jdk/commit/fc314740e947b2338ab9e4d4fce0c4f52de56c4b changed the way we generate `ct.sym` - it now contains `.sig` files also for the current JDK, not only for the past versions. Before this patch, `ct.sym` only contained a list of permitted modules for the current JDK, and the classfiles themselves were read from `lib/modules`.
> 
> The problems (and their solution) I've attempted to tackle here:
>  - since https://github.com/openjdk/jdk/commit/fc314740e947b2338ab9e4d4fce0c4f52de56c4b, the ct.sym accidentally includes all modules for the current release, including non-API/undocumented modules. The proposed solution is to pass the documented modules together with their transitive dependencies as a parameter when constructing ct.sym, then use them to only generate data for these modules.
>  - there are tiny differences between the data that are in `ct.sym` and in the `.sym.txt` historical files, mostly around annotations. The `.sym.txt` files contain references to internal annotations (like `@PreviewFeature`), which are stripped or converted before the `.sig` file is written into `ct.sym`. When generating historical data for JDK N, we run `CreateSymbols` on JDK N, reading the JDK N classfiles, and producing `.sym.txt`. This is done using `--release N`, so that we read the correct span of modules. Sadly, since now `--release N` will always use the `.sig` files, we are loosing a little bit of information esp. around the annotations. The proposal here is to use `--release N` to read the list of modules to cover, and `--source N` to read the actual real classfiles from `lib/modules`. This should basically revert the behavior to the previous state.
>  - this is an existing issue, but one that needs to be fixed. Sealed types are not written and read properly - writing was not storing them, and reading permitted subclasses was happening too late, not on the `header` line. Note that when fixing this, we now must store some of the non-exported elements, which are reachable through the permitted subclasses, so that casting works as expected. Also, since the historical record is incorrect here, I re-run the generator for JDK 17-21 (as sealed c...

Jan Lahoda 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 ten additional commits since the last revision:

 - Removing unneeded exports.
 - Merge branch 'master' into JDK-8321224
 - Reflecting review feedback - keeping CT_TRANSITIVE_MODULES separate from CT_MODULES.
 - Removing trailing whitespace.
 - Ensuring qualified packages are recorded properly.
 - Fixing tests.
 - Adding a way to dump the API.
 - Adding missing file.
 - 8321224: ct.sym for JDK 22 contains references to internal modules

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/16942/files
  - new: https://git.openjdk.org/jdk/pull/16942/files/87927789..ce981117

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=16942&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=16942&range=01-02

  Stats: 56068 lines in 1520 files changed: 31819 ins; 18328 del; 5921 mod
  Patch: https://git.openjdk.org/jdk/pull/16942.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16942/head:pull/16942

PR: https://git.openjdk.org/jdk/pull/16942