fix(assert): prevent stack overflow on cyclic data structures in EqualExportedValues

[AruneshDwivedi]

Problem

assert.EqualExportedValues panics with a stack overflow when comparing structs that contain self-referential pointers (cyclic data structures). The copyExportedFields function recurses infinitely following the cycle until the goroutine stack is exhausted.

Example

type Node struct {
    Self *Node
}

a := &Node{}
a.Self = a
b := &Node{}
b.Self = b
assert.EqualExportedValues(t, a, b) // PANIC: stack overflow

Fix

Added cycle detection to copyExportedFields by tracking visited pointers in a map[uintptr]struct{}. When a pointer is revisited, the function returns nil instead of recursing infinitely.

Changes

• assert/assertions.go: Modified copyExportedFields to accept a seen map for cycle detection
• assert/assertions_test.go: Updated test to use new helper function

Testing

All existing tests pass. The fix prevents stack overflow while maintaining correct behavior for non-cyclic structures.