RFR: 8370976: Review the behavioral changes of core reflection descriptor parsing migration

[Jorn Vernee]

On Fri, 31 Oct 2025 00:00:02 GMT, Chen Liang <liach at openjdk.org> wrote:

> There were a few other holes in the recent migration of BytecodeDescriptor, most notably:
> 
> 1. BytecodeDescriptor is missing checks for `.`, `[` characters, leading, trailing, consecutive `/`, or empty name.
> 2. EnclosingMethod is only validated by hotspot to carry either field or method type. We still need to check for field types
> 
> I have written up the behavioral changes in the CSR. In addition, I have added a few more tests to ensure the failure case behaviors of the migrated use sites.

src/java.base/share/classes/sun/invoke/util/BytecodeDescriptor.java line 160:

> 158:             | (1L << ('/' - CHECK_OFFSET))
> 159:             | (1L << (';' - CHECK_OFFSET))
> 160:             | (1L << ('[' - CHECK_OFFSET));

Are we sure that these are the only 4 non-identifier chars we can see in the string?

src/java.base/share/classes/sun/invoke/util/BytecodeDescriptor.java line 166:

> 164:             int check = str.charAt(index) - CHECK_OFFSET;
> 165:             if ((check & -Long.SIZE) == 0 && (NON_IDENTIFIER_MASK & (1L << check)) != 0) {
> 166:                 break;

Maybe this is a little clearer:
Suggestion:

            if (check < 64 && (NON_IDENTIFIER_MASK & (1L << check)) != 0) {
                break;

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PR Review Comment: https://git.openjdk.org/jdk/pull/28079#discussion_r2546556027
PR Review Comment: https://git.openjdk.org/jdk/pull/28079#discussion_r2546501723