In dev v285.x had a waitgroup panic

[matt2e]

From the logs:
/home/runner/go/pkg/mod/github.com/!t!b!d54566975/ftl@v0.281.3/internal/modulecontext/module_context.go:206 +0x1c5
created by github.com/TBD54566975/ftl/internal/modulecontext.grpcModuleContextSupplier.Subscribe in goroutine 1
/home/runner/go/pkg/mod/github.com/!t!b!d54566975/ftl@v0.281.3/internal/rpc/rpc.go:252 +0x262
github.com/TBD54566975/ftl/internal/rpc.RetryStreamingServerStream[...]({0x127c930, 0xc00040a550}, {0x0, 0x0, 0x0, 0x0, 0x0}, 0xc0003bc200, 0xc000118648, 0xc00033a4a0, ...)
/home/runner/go/pkg/mod/github.com/!t!b!d54566975/ftl@v0.281.3/internal/modulecontext/module_context.go:242 +0x8f
github.com/TBD54566975/ftl/internal/modulecontext.NewDynamicContext.func2({0x126d180, 0xc0003bd200})
/home/runner/.cache/hermit/pkg/go-1.22.2/src/sync/waitgroup.go:87
sync.(*WaitGroup).Done(...)
/home/runner/.cache/hermit/pkg/go-1.22.2/src/sync/waitgroup.go:62 +0xd8
sync.(*WaitGroup).Add(0x126d180?, 0xc0003bd200?)
goroutine 51 [running]:
{"level":"error","attributes":{"module":"kcc","scope":"kcc","deployment":"dpl-kcc-161a9z4k3cc0kvdv"},"time":"2024-07-12T07:25:17.991920295Z"}
panic: sync: negative WaitGroup counter

I thought this would have been fixed earlier here, but is it still happening?
fix: module context errors should not cause a negative wait group (

cc @alec-brooks

[jonathanj-square]

This issue appears to have been reported against a version that does not include fix: a8bc627

That fix puts both await.Done calls behind ReleaseOnce as a means of guarding against multiple invocations.

Furthermore, the stack notes this call-site as the coordinate for the failure:
/home/runner/go/pkg/mod/github.com/!t!b!d54566975/ftl@v0.281.3/internal/modulecontext/module_context.go:242 +0x8f
github.com/TBD54566975/ftl/internal/modulecontext.NewDynamicContext.func2

The line number noted is 242; however, the new line number for this await.Done call is 244. Prior to this fix the line number was 242.

The nested method name noted is modulecontext.NewDynamicContext.func2; however, the new name is modulecontext.NewDynamicContext.func2.1 given this call to await.Done is now embedded inline of modulecontext.NewDynamicContext.func2 after the fix. Prior to the fix it was contained directly in the body of modulecontext.NewDynamicContext.func2.