On Mon, 15 Sep 2025 05:43:43 GMT, Chen Liang <[email protected]> wrote:
> John Rose suggests in > https://github.com/openjdk/jdk/pull/26802#issuecomment-3201402304 that > ClassFile API should validate Utf8Entry length eagerly upon construction. > Currently we validate upon writing to bytes, which avoids validation > overhead. However, given that most class file utf8 data are shorter than 1/3 > of the max length, which is always an encodable length, the performance > impact should be low. > > Preventing the creation of unrepresentable UTF8 entries can prevent passing > such invalid instances around, making such problems easier to debug than a > failure at building. > > Tier 1-3 seems clear. The performance impact to jdk.classfile.Write or any of > the regularly run transformation benchmarks seems neutral, less than 5% > perturbations. > > I will update docs to reflect this change, given how widespread this is > across JDK - it seems the only exempt classes are Signature, ClassSignature, > and MethodSignature. This pull request has now been integrated. Changeset: 3b1eb762 Author: Chen Liang <[email protected]> URL: https://git.openjdk.org/jdk/commit/3b1eb7623180ac1b1d69622481589c43749dbbfc Stats: 380 lines in 10 files changed: 210 ins; 53 del; 117 mod 8367585: Prevent creation of unrepresentable Utf8Entry Reviewed-by: asotona ------------- PR: https://git.openjdk.org/jdk/pull/27281
