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coresmart / persistencejs

persistence.js is an asynchronous Javascript database mapper library. You can use it in the browser, as well on the server (and you can share data models between them).
http://persistencejs.org
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Improper clearing of objects in race conditions #104

Closed ograycode closed 11 years ago

ograycode commented 11 years ago

Problem

When doing multiple queries back-to-back, persistence will return the wrong object when using the .list(tx, callback) function. I fist discussed in the google group earlier today, https://groups.google.com/forum/?fromgroups=#!topic/persistencejs/wChS50a1JRY.

Fix

Call persistence.clean() before making the query to ensure proper clearing of objects and returning to the user what is expected.

Test

The test for this fix is housed inside of https://gist.github.com/3656872. With index.html containing existing code that demonstrates the problem, and index_fixed.html pointing to my cloned repo which demonstrates the fix. The console outputs the object._type.

Before Fix: The console output : https://gist.github.com/3656872#file_console_output.txt. Here, you can clearly see that the wrong objects are being returned.

After Fix: The console output: https://gist.github.com/3656872#file_console_output_fixed.txt. After the fix, you can see that the correct objects are being returned.

Git Commit Message

This fix is to ensure that PersistenceJS always returns only those objects that it has just queried, no matter how fast the queries are happening. By calling persistence.clean(); after we ensure we have a transaction, the following objects are cleared: this.trackedObjects this.objectsToRemove this.objectsRemoved this.globalPropertyListeners this.queryCollectionCache

ograycode commented 11 years ago

Closing this pull request because the diff shows the whole file as changing. Will resubmit.