RFR: 8372787: ModuleReader should throw IOException consistently when using --patch-module and ModuleReader is closed [v2]

[Alan Bateman]

On Mon, 1 Dec 2025 10:28:39 GMT, Jaikiran Pai <jpai at openjdk.org> wrote:

>> Jaikiran Pai has updated the pull request incrementally with two additional commits since the last revision:
>> 
>>  - 8372787: ModuleReader should throw IOException consistently when using --patch-module and ModuleReader is closed
>>  - Revert "8372787: ModulePatcher throws unspecified IllegalStateException upon being invoked after close()"
>>    
>>    This reverts commit 42cfa0aa40926b748c6d7bdf814d85ca1ccd8fed.
>
> src/java.base/share/classes/jdk/internal/module/ModulePatcher.java line 314:
> 
>> 312:          */
>> 313:         public Resource findResource(String name) throws IOException {
>> 314:             ensureOpen();
> 
> Unlike the other methods which have been updated to call the `ensureOpen()`, this `findResource(...)` method isn't part of the `ModuleReader` interface. This only gets called from the `BuiltinClassLoader` when defining a `Class`. I looked up that code in `BuiltinClassLoader` and it already has a catch clause to handle `IOException`, so it felt right to add the `ensureOpen()` check here too.

It would be a serious bug if we could somehow close the ModuleReader under the feet of the built-in class loaders. We could potentially use an assert here.

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PR Review Comment: https://git.openjdk.org/jdk/pull/28569#discussion_r2576544760