Crash in GraphQLQueryWatcher.cancel() and GraphQLQueryWatcher.refetch()

[damian0815]

Summary

When I attempt to call refetch() or cancel() on a GraphQLQueryWatcher i get an EXC_BAD_ACCESS.

• with refetch() it's in GraphQLQueryWatcher.fetch() on the first line ($fetching.mutate {).
  
• with cancel() it's on the first line of the cancel() func fetching.cancellable?.cancel()

Version

1.15.1

Steps to reproduce the behavior

refetch() is being called from the main thread of my app. I have verified that I'm also creating the GraphQLQueryWatcher on the main thread. I've also tried using refetch() in a detached Task (Task.detached), which doesn't help either.

Logs

Backtrace:

Thread 1 Queue : com.apple.main-thread (serial)
#0	0x0000000000000000 in 0x00000000 ()
#1	0x0000000104971580 in GraphQLQueryWatcher.fetch(cachePolicy:) at /Users/damian/Library/Developer/Xcode/DerivedData/XXXX-boiyzzgkimuasqfevhtzbuipxoth/SourcePackages/checkouts/apollo-ios/Sources/Apollo/GraphQLQueryWatcher.swift:72
#2	0x00000001049714dc in GraphQLQueryWatcher.refetch(cachePolicy:) at /Users/damian/Library/Developer/Xcode/DerivedData/XXXX-boiyzzgkimuasqfevhtzbuipxoth/SourcePackages/checkouts/apollo-ios/Sources/Apollo/GraphQLQueryWatcher.swift:68

Anything else?

No response

[damian0815]

Updated - also hitting on .cancel()

[calvincestari]

I was going to ask if you're able to reproduce this in a standalone project that we can debug because we have tests that use both those methods without error.

• refetch test here
• multiple tests in that same file have a teardown block that all call cancel()

But..based on your other comment I wonder if this crash is because of how you're manipulating the cache by deleting the object but not updating the lists that reference that object. So the subsequent fetch is looking for a cache object that isn't there.

Why it's crashing on cancel though I'm not sure. 🤔

[damian0815]

But..based on #3472 (comment) I wonder if this crash is because of how you're manipulating the cache by deleting the object

ahh, that's a good thought but it was crashing before I added that.

[damian0815]

also seeing the issue on v1.15.3. in case it's relevant I am on Xcode 15.4, macOS 14.5, building against Swift 5, targetting macOS 13.1

[calvincestari]

ahh, that's a good thought but it was crashing before I added that.

What happens if you call refetch() with a policy to ignore the cache? Trying to eliminate the cache as a potential factor here.

also seeing the issue on v1.15.3. in case it's relevant I am on Xcode 15.4, macOS 14.5, building against Swift 5, targetting macOS 13.1

We run our unit tests on both Xcode 15.4 and Xcode 16.1 so the tests I referenced earlier are being run on the same platform as you. Shouldn't really matter though.

[damian0815]

I tracked the problem down, it was due to us linking against Apollo libs twice (once in our networking framework and once in the app). Please feel free to close this issue.

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