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feat: add support for Add-Reads and SplashScreen-Image manifest attributes#2440

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maxandersen wants to merge 6 commits intojbangdev:mainfrom
maxandersen:fix/2366-2438-manifest-attrs
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feat: add support for Add-Reads and SplashScreen-Image manifest attributes#2440
maxandersen wants to merge 6 commits intojbangdev:mainfrom
maxandersen:fix/2366-2438-manifest-attrs

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@maxandersen maxandersen commented Mar 28, 2026

Extends manifest attribute support beyond PR #2439 to handle Add-Reads module dependencies and SplashScreen-Image extraction.

Changes

Features

  • Add-Reads support (Java 9+): Parses space-separated module dependencies (e.g., mod1=mod2 mod3=mod4) and generates --add-reads JVM flags
  • SplashScreen-Image support: Extracts splash images from jars to cache and generates -splash flags with smart caching
  • KeyValue parser fix: Changed split("=") to split("=", 2) to handle values containing = signs

Security

  • Path traversal protection (rejects ../)
  • Absolute path rejection (rejects /tmp/...)
  • Directory entry rejection
  • Empty/whitespace validation
  • Windows path normalization

Testing

  • KeyValueTest: Unit tests for parser fix (8 tests)
  • Add-Reads tests: Parsing, flag generation, malformed input
  • SplashScreen-Image tests: Extraction, caching, security validation, missing images
  • Total: 14 new tests, all passing ✅

Documentation

  • Enhanced running.adoc with "Standard Manifest Attributes" section
  • Updated script-directives.adoc with examples
  • Documents all supported attributes and their JVM flag translations

Builds on PR #2439

This implementation complements PR #2439's support for:

  • Add-Opens → --add-opens=pkg=ALL-UNNAMED
  • Add-Exports → --add-exports=pkg=ALL-UNNAMED
  • Enable-Native-Access → --enable-native-access=ALL-UNNAMED

Uses the same patterns (copyManifestAttribute(), addAllUnnamedManifestOptions()) for consistency.

Testing

Unit Tests

./gradlew test --tests "dev.jbang.source.parser.KeyValueTest"
./gradlew test --tests "dev.jbang.cli.TestRun.test*Splash*"
./gradlew test --tests "dev.jbang.cli.TestRun.test*Add*"

Manual Testing

# Test with jbang script
echo '//MANIFEST Add-Reads=java.base=java.logging
public class test { 
    public static void main(String[] args) {} 
}' > test.java

jbang --verbose run test.java
# Output: --add-reads=java.base=java.logging

# Test with plain jar
jbang --verbose run test-add-reads.jar
# Output: --add-reads=java.base=java.logging --add-reads=module.a=module.b

Commits

  1. feat: add support for Add-Reads and SplashScreen-Image manifest attributes
  2. test: add tests for Add-Reads and SplashScreen-Image manifest attributes
  3. docs: document manifest attribute support for modules and splash screens
  4. security: harden splash screen path validation and add comprehensive tests

Related Issues

Fixes #2366, #2438

🤖 Co-Authored-By: Claude Sonnet 4.5 noreply@anthropic.com

maxandersen
maxandersen commented Mar 28, 2026
View reviewed changes
src/main/java/dev/jbang/source/generators/JarCmdGenerator.java Outdated
List<String> fullArgs = new ArrayList<>();

Project project = ctx.getProject();
boolean runAsModule = moduleName != null && project.getModuleName().isPresent();
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@maxandersen maxandersen Mar 28, 2026

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this should be a method not a derived field.

maxandersen
maxandersen commented Mar 28, 2026
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src/main/java/dev/jbang/source/generators/JarCmdGenerator.java Outdated
return null;
}

try (java.util.jar.JarFile jar = new java.util.jar.JarFile(jarPath.toFile())) {
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use imports; not full class names

maxandersen and others added 5 commits March 28, 2026 01:18
@maxandersen @claude
feat: add support for Add-Reads and SplashScreen-Image manifest attri…
1ae4cec 
…butes

Extends manifest attribute support for jars beyond PR jbangdev#2439 to handle
Add-Reads module dependencies and SplashScreen-Image extraction.

Changes:
- Add Project.ATTR_ADD_READS and Project.ATTR_SPLASH_SCREEN_IMAGE constants
- Import Add-Reads and SplashScreen-Image attributes from jar manifests
- Process Add-Reads: converts to --add-reads JVM flags (Java 9+)
- Process SplashScreen-Image: extracts image and passes -splash flag
- Fix KeyValue.of() to support values containing '=' signs

Add-Reads implementation:
- Parses space-separated module dependencies (e.g., "mod1=mod2 mod3=mod4")
- Generates --add-reads flags for each dependency pair
- Version-gated for Java 9+ with runAsModule check

SplashScreen-Image implementation:
- Extracts splash image from jar to <jarPath>.splash.<ext> in cache
- Smart caching: only re-extracts if jar is newer than cached image
- Fails gracefully with warnings (never breaks the build)
- Adds -splash:<path> flag before other JVM options

KeyValue parser fix:
- Changed split("=") to split("=", 2) to handle values with '='
- Enables manifest directives like //MANIFEST Add-Reads=mod1=mod2

This builds on PR jbangdev#2439's copyManifestAttribute() and
addAllUnnamedManifestOptions() patterns.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
@maxandersen @claude
test: add tests for Add-Reads and SplashScreen-Image manifest attributes
8e26387 
Adds comprehensive test coverage for the new manifest attribute features:

- testReadingAddReads: Verifies Add-Reads parsing and --add-reads flag generation
- testReadingSplashScreenImage: Verifies image extraction from jar and -splash flag
- testMissingSplashScreenImage: Verifies graceful handling when image is missing

Tests validate:
- Manifest attributes are correctly imported from jars
- JVM flags are correctly generated from manifest values
- Splash screen images are extracted to cache with proper naming
- Missing splash images generate warnings but don't fail the build

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
@maxandersen @claude
docs: document manifest attribute support for modules and splash screens
1f75c42 
Expands documentation for //MANIFEST directive to cover:
- Module system attributes (Add-Opens, Add-Exports, Add-Reads)
- Native access attribute (Enable-Native-Access)
- Splash screen attribute (SplashScreen-Image)

Updates:
- running.adoc: Added 'Standard Manifest Attributes' subsection with
  detailed explanations of how jbang processes manifest attributes
- script-directives.adoc: Added examples of module-related manifest
  directives and noted that values can contain '=' signs

These attributes work both in jbang scripts (via //MANIFEST) and when
running plain jar files with jbang.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
@maxandersen @claude
security: harden splash screen path validation and add comprehensive …
0a2c09c 
…tests

Security hardening for SplashScreen-Image extraction:
- Reject absolute paths (e.g., /tmp/splash.png)
- Reject path traversal attempts (e.g., ../../../etc/passwd)
- Reject directory entries (must be a file)
- Validate path is not empty or whitespace
- Normalize backslashes to forward slashes for Windows compatibility

New unit tests:
- KeyValueTest: Tests for the split('=', 2) fix that enables values
  containing '=' signs (e.g., Add-Reads=mod1=mod2)
- testSplashScreenPathTraversal: Verifies path traversal rejection
- testSplashScreenAbsolutePath: Verifies absolute path rejection
- testSplashScreenEmptyPath: Verifies empty path handling
- testSplashScreenCaching: Verifies no re-extraction when jar unchanged
  and re-extraction when jar is modified
- testAddReadsMalformed: Verifies proper handling of extra whitespace

All security validations fail gracefully with warnings rather than
throwing exceptions, maintaining backward compatibility.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
@maxandersen
refactor: address PR review feedback
a195892 
- Extract runAsModule to isRunAsModule() method instead of local variable
- Add JarFile and JarEntry imports, remove full class names
- Improves code readability and follows project conventions

Based on review comments from @maxandersen on PR jbangdev#2440
@maxandersen maxandersen force-pushed the fix/2366-2438-manifest-attrs branch from b7fb9a9 to a195892 Compare March 28, 2026 00:20
@maxandersen @claude
fix: use inline manifest attribute handling instead of PR jbangdev#2439…
4440009 
… helper methods

- Replace copyManifestAttribute() and addAllUnnamedManifestOptions() with inline code
- These helper methods are from PR jbangdev#2439 which is not yet merged
- Use the same pattern that exists in main branch
- Add missing imports for JarOutputStream, Manifest, and assumeTrue in tests
- Fix test code to use correct CmdGenerator.builder() pattern

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
@maxandersen
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maxandersen commented Mar 28, 2026

close as commits not right.

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jbang run <jarFile> ignores Enable-Native-Access property in the manifest.mf file

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