Fix cache manifest not saving: open MPQ writable in ProjectConfigBuilder#1176
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Frotty merged 1 commit intowurstscript:masterfrom Apr 1, 2026
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`ProjectConfigBuilder.apply()` opens the target map MPQ to save the updated cache manifest, but passes `readOnly=true` to `getEditor()`. The subsequent `saveManifest()` call tries to insert a file via `mpq.insertFile()`, which calls `JMpqEditor.deleteFile()` internally. JMPQ3 throws `NonWritableChannelException` (with a null message) when the editor is read-only, resulting in: Warning: Could not save manifest to MPQ: null This silently breaks the build caching system introduced in wurstscript#1096 — every build becomes a full rebuild because the manifest is never persisted. Fix: change `readOnly` from `true` to `false` so the manifest can actually be written.
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Summary
ProjectConfigBuilder.apply()opens the target map MPQ withreadOnly=trueto save the updated cache manifest. The subsequentsaveManifest()→mpq.insertFile()call fails because JMPQ3'sJMpqEditor.deleteFile()throwsNonWritableChannelExceptionwhen the editor is read-only.This produces the warning:
The
nullis becauseNonWritableChannelException()has no message by default.This silently breaks the build caching system introduced in #1096 — every build becomes a full rebuild because the manifest is never persisted to the MPQ.
Fix
One-line change:
readOnlyfromtruetofalseatProjectConfigBuilder.java:101so the manifest can actually be written.Call chain
ProjectConfigBuilder.apply()line 101:MpqEditorFactory.getEditor(Optional.of(targetMap), true)— read-onlyImportFile.saveManifest(mpq, manifest)ImportFile.saveManifest()line 224:mpq.insertFile(MANIFEST_MPQ_PATH, data)Jmpq3BasedEditor.insertFile()line 30:getEditor().deleteFile(filenameInMpq)— throws NonWritableChannelExceptionTest plan