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Several VM and native operations diverge from HotSpot: failed bootstraps run again, exception handlers can catch unrelated same-named classes, and open-file attributes can describe the wrong file after unlink. Fix these paths and the other confirmed audit defects in their shared implementations.
Cache failed invokedynamic linkage and share resolved dynamic constants between ldc and bootstrap arguments, including primitive constants.
Resolve exception catch types through the defining loader, allowing loading to suspend without re-executing the throwing instruction. A failed catch-type load restarts dispatch at that handler's bytecode position. Cover interpreted, compiled and hidden classes.
Apply and report host POSIX permissions, preserving host errno and the existing no-op for virtual backends without permission bits. Preserve descriptor size, mode and inode identity after rename/unlink, and return the native error for invalid descriptors.
Follow host symlinks before .. for reads and mutations, preserving terminal symlinks and virtual mount selection.
Reject dictionaries while a wrapped deflater is active, preserving zero-length output, finish and reset behavior.
Exclude private static methods from overload selection while preserving the package-private and protected helpers used by native callbacks.
Validation: failing-before/passing-after HotSpot comparisons for the confirmed defects; DeflaterState, ZipStreams, LinkageCaching, LoaderCatch, FstatAfterUnlink, OpenFileInodes, PosixPermissions, and host symlink operations pass. The native-callback, library and JS-proxy suites, VFS regressions and TypeScript typecheck pass. CI also runs the new permission-error, catch-resolution-failure and reference-exit regressions, plus broader verification.
Additional review at a28620f covered the files skipped by the review bot: test/paths/SymlinkDotDot.java and the full test/programs.test.ts diff. No findings. Coverage included read/create/move/delete paths, terminal-symlink target preservation, the reference exit assertion, temporary-file cleanup, Windows skip, and ONLY / test-name selection.
Noticed, not fixed
The support docs now state the existing stored-block compression limitation and explain why browser fetch cannot expose manual redirects. Java long results keep the established JS-number conversion; the browser guide documents its precision limit and exact string/array alternatives.
Filesystem metadata now includes permission bits, and file descriptors retain correct inode and attribute information after files are renamed or removed.
Path resolution better reflects symlinks and .. segments on supported host filesystems.
File permission changes now report errors for missing files, invalid descriptors, and read-only filesystems.
Bug Fixes
Static and instance method lookups now consistently expose only public methods.
Improved handling of Java exceptions, dynamic constants, and linkage failures.
Deflater now handles empty output buffers and dictionary updates more consistently.
Documentation
Clarified Java long conversions, compression behavior, and browser redirect handling.
This pull request updates filesystem path resolution and POSIX file metadata, JVM linkage and exception handling, Java library method visibility, and Deflater behavior. It also adds regression tests and updates browser and runtime documentation.
VFS.resolvePath delegates eligible paths to a backend resolver. NodeBackend resolves paths for the root backend, and tests compare symlink paths containing .. with HotSpot behavior.
POSIX metadata and open files
Layer / File(s)
Summary
File metadata and shared inode tracking src/fs.ts, src/node.ts, src/natives/io.ts, src/natives/nio.ts
Stat includes mode bits, and host stat reports them. File operations and NIO use shared inode tracking for attributes and file keys.
Detached file operations and permissions src/natives/io.ts, src/natives/nio.ts, test/java/FstatAfterUnlink.java, test/java/PosixPermissions.java
Rename and removal preserve metadata for affected open files. NIO reports detached-file attributes and implements chmod0 and fchmod0; Java tests cover permissions and file descriptors after unlink.
JVM linkage and exception handling
Layer / File(s)
Summary
Dynamic constant and call-site caching src/indy.ts, src/jvm.ts, src/jit.ts, test/java/LinkageCaching.java
Dynamic constants use the constant-pool cache. Linkage failures of type LinkageError are cached, and JIT execution falls back for cached PendingThrow sites.
Exception handling resolves unloaded catch classes through a native frame. Tests exercise catch behavior across class-loader boundaries.
Library method visibility
Layer / File(s)
Summary
Public method lookup src/library.ts, test/library/Lib.java, test/library.test.ts, docs/browser.md
Static and instance method lookup excludes non-public methods. Tests cover static overload selection and hidden methods; documentation describes public method exposure.
Deflater behavior
Layer / File(s)
Summary
Deflater state handling src/natives/zip.ts, test/java/DeflaterState.java, docs/support.md
Deflater rejects dictionary changes after wrapped output begins and returns immediately for an empty output buffer. The documentation describes its output and compression behavior.
Browser interoperability documentation
Layer / File(s)
Summary
Numeric conversion and HTTP behavior docs/browser.md, docs/support.md
The documentation describes Java long conversion and precision limits, as well as browser fetch redirect handling and complete response-body reads.
Project516/java-web#8: Adds the Backend.chmod contract and host permission changes, which connect to this pull request’s filesystem permission updates.
Merge Risk: Moderate · up to acc62
Setting file permissions on a writable in-memory mount, or after a host chmod failure, can now fail with a read-only-filesystem error where it previously succeeded silently. Fix the error mapping before merging. The symlink HotSpot comparison test should also assert that the reference run succeeds.
Pre-merge checks: 4 · 1
Failed checks: 1 warning
Check name
Status
Explanation
Resolution
Docstring Coverage
Docstring coverage is 17.39% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff with cyclomatic complexity of at least 2. Documenta…
Write docstrings for the functions missing them to satisfy the coverage threshold.
Passed checks: 4 passed
Check name
Status
Explanation
Title check
The title clearly summarizes the pull request’s main purpose: fixing remaining compatibility defects identified by the audit.
Linked Issues check
Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check
Check skipped because no linked issues were found for this pull request.
Description check
The pull request description directly covers the VM, native filesystem, symlink, deflater, library, documentation, and test changes in the changeset.
Full details: Docstring Coverage
Explanation
Docstring coverage is 17.39% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff with cyclomatic complexity of at least 2. Documentation-only edits and deletions within surviving functions are included; unchanged diff context and fully deleted functions are excluded. Analyzed 23 functions across 20 files. (2 skipped: 2 unsupported.)
Resolution
Write docstrings for the functions missing them to satisfy the coverage threshold.
Finishing Touches
Generate docstrings
Commit to this branch
Create a new PR
Simplify code
Commit to this branch
Create a new PR
Autofix · Keep fixing CodeRabbit findings and required CI, and resolving merge conflicts
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I’m a rabbit checking files by moonlit light, I follow each link where .. turns right. Long values hop past numbers’ safe fence, Cached calls remember their last consequence. I nibble stored blocks, then bound away, With open-file metadata tucked safe for the day.
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Recent review info
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Plan: Advanced
Run ID: 2590a748-2b55-436b-80fd-800220e14a14
Commits
Reviewing files that changed from the base of the PR and between 608479d and acc624b.
Files selected for processing: 22
docs/browser.md
docs/support.md
src/fs.ts
src/indy.ts
src/interp.ts
src/jit.ts
src/jvm.ts
src/library.ts
src/natives/io.ts
src/natives/nio.ts
src/natives/zip.ts
src/node.ts
test/fs.test.ts
test/java/DeflaterState.java
test/java/FstatAfterUnlink.java
test/java/LinkageCaching.java
test/java/LoaderCatch.java
test/java/PosixPermissions.java
test/library.test.ts
test/library/Lib.java
test/paths/SymlinkDotDot.java
test/programs.test.ts
Included review availability: This review used your included allowance. Your plan provides up to 1 included review per hour; 0 remain after this review.
Recent review details
Context from checks skipped due to timeout: 6
GitHub Check: jtreg / run (3)
GitHub Check: jtreg / run (1)
GitHub Check: jtreg / run (4)
GitHub Check: jtreg / run (2)
GitHub Check: CodeRabbit
GitHub Check: test
Additional context used
Learnings: 2
Learning: 2026-11-01T20:52:55.551Z
Learnt from: CR
Repo: Project516/java-web PR: 0
File: AGENTS.md:0-0
Timestamp: 2026-11-01T20:52:55.551Z
Learning: Source excerpt:
# java-web
## Direction
- Prove it with tests: programs whose output must match HotSpot exactly, and
OpenJDK's own regression tests where they can run.
Applied to files:
test/programs.test.ts
Learning: 2026-11-01T20:52:55.551Z
Learnt from: CR
Repo: Project516/java-web PR: 0
File: AGENTS.md:0-0
Timestamp: 2026-11-01T20:52:55.551Z
Learning: Source excerpt:
# java-web
## Direction
- Compatibility first. Run JDK classes unmodified and implement what HotSpot
does for them (natives, VM upcalls, init order). Do not patch or replace JDK
classes. When behavior differs from HotSpot, HotSpot is right.
Applied to files:
src/jvm.ts
ast-grep (0.51.1)
test/java/PosixPermissions.java
[warning] 14-14: Temporary file not deleted
Context: Files.createTempFile("java-web-mode", ".tmp")
Note: [CWE-377] Insecure Temporary File. Security best practice.
(tempfile-delete)
test/java/FstatAfterUnlink.java
[warning] 25-25: Temporary file not deleted
Context: Files.createTempFile("fstat-unlink", ".tmp")
Note: [CWE-377] Insecure Temporary File. Security best practice.
[Medium] 24-24: AvoidUsingOctalValues (Error Prone): Avoid integer literals that start with zero (interpreted as octal), remove the leading 0 to get a decimal literal (or use explicit 0x, 0b prefixes)
(AvoidUsingOctalValues (Error Prone))
[Medium] 28-28: AvoidUsingOctalValues (Error Prone): Avoid integer literals that start with zero (interpreted as octal), remove the leading 0 to get a decimal literal (or use explicit 0x, 0b prefixes)
(AvoidUsingOctalValues (Error Prone))
test/java/FstatAfterUnlink.java
[Medium] 40-40: AvoidUsingOctalValues (Error Prone): Avoid integer literals that start with zero (interpreted as octal), remove the leading 0 to get a decimal literal (or use explicit 0x, 0b prefixes)
(AvoidUsingOctalValues (Error Prone))
[Medium] 48-48: AvoidUsingOctalValues (Error Prone): Avoid integer literals that start with zero (interpreted as octal), remove the leading 0 to get a decimal literal (or use explicit 0x, 0b prefixes)
Although openFile does not initially set ino, removePath calls detachFile first, and detachFile stores the inode before the path entry is deleted. The detached fstat0 path therefore uses the stored inode. Assigning ino inside openFile is not required for this case.
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This PR fixes multiple HotSpot audit compatibility defects: invokedynamic bootstrap caching (including failed bootstraps and primitive dynamic constants), exception catch type resolution through defining loaders, file inode/permission preservation after rename/unlink, host symlink resolution before '..', Deflater dictionary rejection during active compression, and library call restriction to public methods. Tests validate each fix against HotSpot behavior. However, the exception handler resolution in src/interp.ts has a defect: when catch type resolution fails (e.g., NoClassDefFoundError), the code catches the error and continues to subsequent handlers instead of throwing immediately, violating the JVM spec which requires the linkage error to be thrown at the point of the failing catch clause.
review-bot, model nvidia/nemotron-3-ultra-550b-a55b:free, verdict request_changes
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This PR fixes several audit compatibility defects: invokedynamic linkage caching, exception catch type resolution, file inode/permission preservation after unlink/rename, host symlink resolution before '..', Deflater dictionary rejection, and private static method exclusion. However, there are clear defects in the exception handling logic (interp.ts), primitive dynamic constant caching (indy.ts), NodeBackend symlink resolution for non-root mounts (node.ts), and unsafe Map iteration during rename (io.ts).
Not approved: 1 earlier point is still open in the threads.
review-bot, model nvidia/nemotron-3-ultra-550b-a55b:free, verdict comment
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This PR fixes multiple audit compatibility defects: invokedynamic linkage caching for failed bootstraps and primitive dynamic constants; exception catch-type resolution through defining loader with restart-on-failure semantics; POSIX permission reporting with host errno preservation; inode identity preservation after rename/unlink; symlink resolution before '..' components; Deflater dictionary rejection during active compression; and private static method exclusion from JS overload selection. A clear bug exists in src/natives/io.ts where a Map is modified during keys() iteration. The exception handler restart logic in src/interp.ts was flagged in earlier review as diverging from JVM spec (restarts from handler 0 instead of failing handler), though PR claims HotSpot parity.
Not approved: the diff of test/paths/SymlinkDotDot.java, test/programs.test.ts was too large to read.
review-bot, model nvidia/nemotron-3-ultra-550b-a55b:free, verdict comment
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Several VM and native operations diverge from HotSpot: failed bootstraps run again, exception handlers can catch unrelated same-named classes, and open-file attributes can describe the wrong file after unlink. Fix these paths and the other confirmed audit defects in their shared implementations.
ldcand bootstrap arguments, including primitive constants...for reads and mutations, preserving terminal symlinks and virtual mount selection.Validation: failing-before/passing-after HotSpot comparisons for the confirmed defects;
DeflaterState,ZipStreams,LinkageCaching,LoaderCatch,FstatAfterUnlink,OpenFileInodes,PosixPermissions, and host symlink operations pass. The native-callback, library and JS-proxy suites, VFS regressions and TypeScript typecheck pass. CI also runs the new permission-error, catch-resolution-failure and reference-exit regressions, plus broader verification.Additional review at
a28620fcovered the files skipped by the review bot:test/paths/SymlinkDotDot.javaand the fulltest/programs.test.tsdiff. No findings. Coverage included read/create/move/delete paths, terminal-symlink target preservation, the reference exit assertion, temporary-file cleanup, Windows skip, andONLY/ test-name selection.Noticed, not fixed
The support docs now state the existing stored-block compression limitation and explain why browser fetch cannot expose manual redirects. Java
longresults keep the established JS-number conversion; the browser guide documents its precision limit and exact string/array alternatives.