Crash on `info locals` on OS X

[go-delve]

Crash on `info locals` on OS X

[derekparker]

Thanks, I was just able to reproduce this locally. Looks like an issue with cgo enabled programs (in your example, include net/http enables cgo).

I'll investigate this.

[bforsyth927]

My friend and I hit this issue and debugged through it. At least for all the cases we hit (both for 'info vars' and 'info locals') the underlying issue was always that it was drilling into an array of strings. And it would blow up when one of the strings was nil (length == 0, ptr == 0). The fix or workaround I used in my own copy of Delve is pretty straightforward. Basically just return the empty string "" out of readString, rather than attempting to dereference a null pointer and construct a string struct at that bogus address. I'm happy to generate a pull request if you like. But I'm not (yet) set up to run tests with Delve so it might be a few days before I can get around to it. What would you like me to do?

diff --git a/proctl/variables.go b/proctl/variables.go
index 4554bc4..f0735bf 100644
--- a/proctl/variables.go
+++ b/proctl/variables.go
@@ -693,6 +693,10 @@ func (thread *ThreadContext) readString(addr uintptr) (string, error) {
}
addr = uintptr(binary.LittleEndian.Uint64(val))

•   if addr == 0 {
  

•           return "", err
  

•   }
  

• val, err = thread.readMemory(addr, strlen)
  if err != nil {
          return "", err
  

[derekparker]

@bforsyth927 that looks like a pretty reasonable patch. If you submit a PR I'll merge it in.