delve-debug-demo

README

go-delve-debug-sample

Go sample repo for demonstrating TDD and delve debugging.

What you can learn from this repo

1. About VSCode Go extension and delve
2. delve tutorial (Breakpoint, Hit Count, goroutine, Local vars)
3. Go race detector

Explanation

git clone https://github.com/go-zen-chu/delve-debug-demo.git

Understanding problem

1. Explain about main.go and count.go
2. Run go run main.go
3. In count.go, open Command Palette and run Go: generate test for file & Go: generate test for this function
4. Implement count_test.go and run go test -v ./count
5. Open Command Palette and run Go: Toggle Test Coverage
6. Discuss why the test failed.

Answer

1. Create break point on count with Expression 90 < count && count < 100 (break) and 990 < count && count < 1000 (doesn't always break)
2. Set break point in count_debug.go and run Parallel1000countDebug from count_test.go
3. Fix count.go and run test with success.

Appendix

Try, go run --race main.go

==================
WARNING: DATA RACE
Read at 0x00c00013a018 by goroutine 8:
  github.com/go-zen-chu/delve-debug-demo/count.Parallel1000count.func1()
      /Users/amasuda/dev/delve-sample/count/count.go:17 +0x8d

Previous write at 0x00c00013a018 by goroutine 7:
  github.com/go-zen-chu/delve-debug-demo/count.Parallel1000count.func1()
      /Users/amasuda/dev/delve-sample/count/count.go:17 +0xa4

Goroutine 8 (running) created at:
  github.com/go-zen-chu/delve-debug-demo/count.Parallel1000count()
      /Users/amasuda/dev/delve-sample/count/count.go:15 +0x84
  main.main()
      /Users/amasuda/dev/delve-sample/main.go:10 +0x29

Goroutine 7 (finished) created at:
  github.com/go-zen-chu/delve-debug-demo/count.Parallel1000count()
      /Users/amasuda/dev/delve-sample/count/count.go:15 +0x84
  main.main()
      /Users/amasuda/dev/delve-sample/main.go:10 +0x29
==================
1000 にならんわけないやろww
-> 998
なんでや!!
Found 1 data race(s)
exit status 66