A database modified in Linux fails to open in Windows?

[aaclayton]

We have been working with classic-level as the data backend for an application that supports Windows/Mac/Linux. The data stored by the application needs to be portable. We had not encountered problems with this, but I have today encountered a scary problem where a database most recently updated in a Linux environment can no longer be opened in Windows:

Context

• The database was loaded and modified in Amazon Linux 2 using Node v16.19.0
• The database is then attempted to be opened in Windows 11 using Node v18.13.0
• Both environments using classic-level 1.2.0

Error

When attempting to call await db.open():

ModuleError: Failed to connect to database "actors": Database is not open
    at maybeOpened (C:\Users\aaclayton\Documents\Foundry\foundryvtt\node_modules\abstract-level\abstract-level.js:133:18)
    at C:\Users\aaclayton\Documents\Foundry\foundryvtt\node_modules\abstract-level\abstract-level.js:160:13
    at process.processTicksAndRejections (node:internal/process/task_queues:77:11) {
  code: 'LEVEL_DATABASE_NOT_OPEN',
: The filename, directory name, or volume label syntax is incorrect. C:\Users\aaclayton\Documents\Foundry\FoundryData\Data\worlds\ember-dev\data\actors/MANIFEST-000021
  ] {
    code: 'LEVEL_IO_ERROR'
  }
}

Contents of the database folder are as follows:

The CURRENT file does reference MANIFEST-000021.

This error is very alarming, because we had been operating under the expectation that the databases created and modified by LevelDB (and therefore classic-level) are portable. Is this expectation wrong? Are there any troubleshooting steps or further details that I can provide to help diagnose the problem?

The absolute path (location) which I'm providing to the ClassicLevel constructor is C:\Users\aaclayton\Documents\Foundry\FoundryData\Data\worlds\ember-dev\data\actors. Something internal to ClassicLevel (or LevelDB) is appending the manifest file to this path but using a / separator rather than a windows path separator. I don't know whether this is part of the issue or innocuous.

This error is not reproducible with every DB I create in a Linux environment and transfer to windows. I have had success moving databases around before (in either direction). I have not encountered this error before but it is highly troubling. Thank you very much for your guidance.

[aaclayton]

An update to anyone who comes searching and finds this issue. The root cause of the problem was line ending conversion behavior of git on Windows that, when the data was pulled was attempting to change line endings in the the LevelDB binary files which caused them to become corrupted.

There are two solutions that we found worked. We could solve the problem by doing either of the following:

1. Git config core.autocrlf set to input to avoid changing line endings when pulling code. (https://git-scm.com/book/en/v2/Customizing-Git-Git-Configuration)
2. Add .gitattributes to the project with a data/** binary rule targetting all the files generated by LevelDB (https://docs.github.com/en/get-started/getting-started-with-git/configuring-git-to-handle-line-endings)

I think the exact issue is that since the MANIFEST-* file is binary, but does not use a file extension that is recognizable as such, git on Windows was trying to do line ending conversion in that file.