Port FxCop rule CA2000: DisposeObjectsBeforeLosingScope

[ghost]

Title: Dispose Objects Before Losing Scope

Description:

Because an exceptional event might occur that will prevent the finalizer of an object from running, the object should be explicitly disposed before all references to it are out of scope.

Dependency: Dataflow

Notes:

[srivatsn]

Blocked on dataflow analysis

[alaforte]

I would be grateful if you will port this rule. Thank you

[tulandor]

Would be great to have this rule. Is there an update on the status of this?

[gafter]

CA2000 was implemented in the C# compiler as a proof of concept some time ago. We removed it from the compiler as the intent is to expand the scope of what analyzers can do to cover these kinds of use cases:

• dotnet/roslyn@8474c25
• dotnet/roslyn@76911d6

I believe our intent is that the IOperation APIs should eventually be capable of expressing this kind of rule. But we still have a long way to go before that is possible.

[mavasani]

Need to ensure that issues mentioned in #1404 are addressed when this is implemented.

[alaforte]

Sorry, I didn't got the point Thank you 2017-11-27 18:00 GMT+01:00 Manish Vasani <[email protected]>:

…

Need to ensure that issues mentioned in #1404 <#1404> are addressed when this is implemented. — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#476 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ACmksuOfT_YDd-msutmOwCr0uPplD-X_ks5s6uqfgaJpZM4Gm-uB> .

[drauch]

What's the status on this one? : ) Since we've ported our projects to the new format we cannot use FxCop anymore - we still want to get warned when not disposing objects! Is there a workaround so that the compiler outputs a warning? Some kind of analyzer? At least a beta analyzer?

[sharwell]

💡 In the meantime, the DotNetAnalyzers/IDisposableAnalyzers project by @JohanLarsson may provide the desired functionality.

[mavasani]

@drauch We are currently working on preliminary DFA based experimental analyzer for dispose rules. We hope to have a beta package with the experimental DFA rules published in a few weeks.

[drauch]

Thanks @sharwell , it looks really nice at first sight. I'll give it a try!

[mavasani]

A PR for preliminary dataflow analysis based implementation of this rule is out for review: #1583

As mentioned in the PR, following are the TODOs to bring it to parity with original FxCop implementation:

1. Analyze exceptional code paths (Analyze exceptional code paths in CA2000 (dispose objects before losing scope) #1580)
2. Path sensitive analysis (Perform path sensitive analysis for dataflow based dispose rules #1581)
3. Improve preciseness by moving to compiler CFG (Issues in preliminary DFA implementation due to lack of precise CFG #1567)

We hope to address these TODOs soon.

[mavasani]

This rule has been implemented in the experimental DFA package. #1583 (comment) lists the TODO items, each of which are tracked with separate issues. Marking this issue as complete.