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package mapr
import (
"testing"
"time"
)
// TestMergeNoblockSemaphoreReleasedOnPanic verifies that MergeNoblock releases
// the semaphore even when g.merge panics (e.g. due to a nil GroupSet).
// Without the fix (using defer), the semaphore would be leaked and subsequent
// calls like NumSets would deadlock forever.
func TestMergeNoblockSemaphoreReleasedOnPanic(t *testing.T) {
g := NewGlobalGroupSet()
// Calling MergeNoblock with a nil *GroupSet causes a nil-pointer dereference
// inside g.merge when it iterates over group.sets. We catch the panic in a
// goroutine and verify that the GlobalGroupSet is still usable afterwards.
done := make(chan struct{})
go func() {
defer func() {
// Recover the expected panic so the goroutine exits cleanly.
if r := recover(); r == nil {
t.Errorf("expected a panic from MergeNoblock with nil GroupSet, got none")
}
close(done)
}()
// This must panic internally; with the bug the semaphore is never released.
//nolint:staticcheck // intentional nil dereference to exercise the panic path
g.MergeNoblock(nil, nil) //nolint:errcheck
}()
// Wait for the goroutine to finish (panic recovered).
select {
case <-done:
case <-time.After(5 * time.Second):
t.Fatal("timed out waiting for MergeNoblock panic to be recovered")
}
// After the panic the semaphore must have been released by the deferred
// release in MergeNoblock. If the bug is present NumSets acquires the same
// 1-slot semaphore and blocks forever, causing the test to time out.
result := make(chan int, 1)
go func() {
result <- g.NumSets()
}()
select {
case n := <-result:
if n != 0 {
t.Errorf("expected 0 sets in empty GlobalGroupSet, got %d", n)
}
case <-time.After(5 * time.Second):
t.Fatal("NumSets deadlocked: semaphore was not released after MergeNoblock panic (bug reproduced)")
}
}
// TestMergeNoblockNormalOperation verifies the non-panic happy path still works
// correctly: a successful merge returns (true, nil) and NumSets reflects the
// merged data.
func TestMergeNoblockNormalOperation(t *testing.T) {
g := NewGlobalGroupSet()
group := NewGroupSet()
// Populate the group set with one entry so there is something to merge.
set := NewAggregateSet()
set.FValues["count"] = 1
group.sets["key1"] = set
// A minimal query is enough; the merge loop only needs query.Select which
// can be empty for this structural test (no select conditions to iterate).
query := &Query{}
merged, err := g.MergeNoblock(query, group)
if err != nil {
t.Errorf("unexpected error from MergeNoblock: %v", err)
}
if !merged {
t.Error("expected MergeNoblock to return merged=true when semaphore is free")
}
// After merging, NumSets must return 1 and must not deadlock.
result := make(chan int, 1)
go func() {
result <- g.NumSets()
}()
select {
case n := <-result:
if n != 1 {
t.Errorf("expected 1 set after merge, got %d", n)
}
case <-time.After(5 * time.Second):
t.Fatal("NumSets deadlocked after normal MergeNoblock (unexpected)")
}
}
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