Panic caused by View.cleanup cleaning up View.buffer too eagerly

[erbridge]

Captured by the comment here.

==================
WARNING: DATA RACE
Read by goroutine 11:
  github.com/limetext/lime/backend.(*WatchedUserFile).Name()
      /home/felix/devel/lime/src/github.com/limetext/lime/backend/watched.go:39 +0x74
  github.com/limetext/lime/backend.(*WatchedUserFile).Reload()
      /home/felix/devel/lime/src/github.com/limetext/lime/backend/watched.go:46 +0x15b
  github.com/limetext/lime/backend.func·004()
      /home/felix/devel/lime/src/github.com/limetext/lime/backend/editor.go:444 +0x17b
  github.com/limetext/lime/backend.(*Editor).observeFiles()
      /home/felix/devel/lime/src/github.com/limetext/lime/backend/editor.go:446 +0x1dc

Previous write by goroutine 64:
  github.com/limetext/lime/backend.(*View).cleanup()
      /home/felix/devel/lime/src/github.com/limetext/lime/backend/view.go:658 +0xc5
  github.com/limetext/lime/backend.(*View).parsethread()
      /home/felix/devel/lime/src/github.com/limetext/lime/backend/view.go:198 +0x2c3

Goroutine 11 (running) created at:
  github.com/limetext/lime/backend.GetEditor()
      /home/felix/devel/lime/src/github.com/limetext/lime/backend/editor.go:148 +0x6d8
  github.com/limetext/lime/backend.init·1()
      /home/felix/devel/lime/src/github.com/limetext/lime/backend/editor.go:24 +0x4b
  github.com/limetext/lime/backend.init()
      /home/felix/devel/lime/src/github.com/limetext/lime/backend/window.go:125 +0xa09
  github.com/limetext/lime/backend/commands.init()
      /home/felix/devel/lime/src/github.com/limetext/lime/backend/commands/window_test.go:52 +0xc5
  main.init()
      github.com/limetext/lime/backend/commands/_test/_testmain.go:134 +0x93

Goroutine 64 (finished) created at:
  github.com/limetext/lime/backend.newView()
      /home/felix/devel/lime/src/github.com/limetext/lime/backend/view.go:69 +0x1fe
  github.com/limetext/lime/backend.(*Window).NewFile()
      /home/felix/devel/lime/src/github.com/limetext/lime/backend/window.go:27 +0xa3
  github.com/limetext/lime/backend.(*Window).OpenFile()
      /home/felix/devel/lime/src/github.com/limetext/lime/backend/window.go:67 +0x45
  github.com/limetext/lime/backend/commands.TestSaveAs()
      /home/felix/devel/lime/src/github.com/limetext/lime/backend/commands/save_test.go:84 +0x34b
  testing.tRunner()
      /home/felix/.gvm/gos/go1.3.1/src/pkg/testing/testing.go:422 +0x10f
==================
panic: runtime error: invalid memory address or nil pointer dereference
[signal 0xb code=0x1 addr=0x40 pc=0x5816af]

goroutine 26 [running]:
runtime.panic(0x7953e0, 0xbb2653)
    /home/felix/.gvm/gos/go1.3.1/src/pkg/runtime/panic.c:279 +0xf5
github.com/limetext/lime/backend.(*WatchedUserFile).Name(0xc2080c00f0, 0x0, 0x0)
    /home/felix/devel/lime/src/github.com/limetext/lime/backend/watched.go:39 +0x9f
github.com/limetext/lime/backend.(*WatchedUserFile).Reload(0xc2080c00f0)
    /home/felix/devel/lime/src/github.com/limetext/lime/backend/watched.go:46 +0x15c
github.com/limetext/lime/backend.func·004()
    /home/felix/devel/lime/src/github.com/limetext/lime/backend/editor.go:444 +0x17c
github.com/limetext/lime/backend.(*Editor).observeFiles(0xc208056000)
    /home/felix/devel/lime/src/github.com/limetext/lime/backend/editor.go:446 +0x1dd
created by github.com/limetext/lime/backend.GetEditor
    /home/felix/devel/lime/src/github.com/limetext/lime/backend/editor.go:148 +0x6d8

goroutine 16 [chan receive]:
testing.RunTests(0x880dd0, 0xbb4060, 0x2c, 0x2c, 0x7f5a7347ee01)
    /home/felix/.gvm/gos/go1.3.1/src/pkg/testing/testing.go:505 +0xbb8
testing.Main(0x880dd0, 0xbb4060, 0x2c, 0x2c, 0xbda660, 0x0, 0x0, 0xbda660, 0x0, 0x0)
    /home/felix/.gvm/gos/go1.3.1/src/pkg/testing/testing.go:435 +0xa3
main.main()
    github.com/limetext/lime/backend/commands/_test/_testmain.go:133 +0xdd

goroutine 19 [finalizer wait]:
runtime.park(0x435b80, 0xbd65b0, 0xbb55a9)
    /home/felix/.gvm/gos/go1.3.1/src/pkg/runtime/proc.c:1369 +0x89
runtime.parkunlock(0xbd65b0, 0xbb55a9)
    /home/felix/.gvm/gos/go1.3.1/src/pkg/runtime/proc.c:1385 +0x3b
runfinq()
    /home/felix/.gvm/gos/go1.3.1/src/pkg/runtime/mgc0.c:2644 +0xcf
runtime.goexit()
    /home/felix/.gvm/gos/go1.3.1/src/pkg/runtime/proc.c:1445

goroutine 21 [chan receive]:
github.com/quarnster/util/text.(*SerializedBuffer).worker(0xc2080240e8)
    /home/felix/devel/lime/src/github.com/quarnster/util/text/serialized_buffer.go:40 +0x89
created by github.com/quarnster/util/text.(*SerializedBuffer).init
    /home/felix/devel/lime/src/github.com/quarnster/util/text/serialized_buffer.go:26 +0xc0

goroutine 22 [runnable]:
github.com/howeyc/fsnotify.(*Watcher).readEvents(0xc20808a120)
    /home/felix/devel/lime/src/github.com/howeyc/fsnotify/fsnotify_linux.go:276 +0xb4a
created by github.com/howeyc/fsnotify.NewWatcher
    /home/felix/devel/lime/src/github.com/howeyc/fsnotify/fsnotify_linux.go:126 +0x372

goroutine 23 [chan send]:
github.com/howeyc/fsnotify.(*Watcher).purgeEvents(0xc20808a120)
    /home/felix/devel/lime/src/github.com/howeyc/fsnotify/fsnotify.go:44 +0x350
created by github.com/howeyc/fsnotify.NewWatcher
    /home/felix/devel/lime/src/github.com/howeyc/fsnotify/fsnotify_linux.go:127 +0x38a

goroutine 24 [chan receive]:
github.com/limetext/lime/backend/logger.(*Logger).handle(0xc208048060)
    /home/felix/devel/lime/src/github.com/limetext/lime/backend/logger/logger.go:32 +0x75
created by github.com/limetext/lime/backend/logger.NewLogger
    /home/felix/devel/lime/src/github.com/limetext/lime/backend/logger/logger.go:27 +0xc4

goroutine 25 [chan receive]:
github.com/limetext/lime/backend.(*Editor).inputthread(0xc208056000)
    /home/felix/devel/lime/src/github.com/limetext/lime/backend/editor.go:364 +0x147
created by github.com/limetext/lime/backend.GetEditor
    /home/felix/devel/lime/src/github.com/limetext/lime/backend/editor.go:147 +0x6ac

goroutine 311 [chan receive]:
github.com/quarnster/util/text.(*SerializedBuffer).worker(0xc2081ac878)
    /home/felix/devel/lime/src/github.com/quarnster/util/text/serialized_buffer.go:40 +0x89
created by github.com/quarnster/util/text.(*SerializedBuffer).init
    /home/felix/devel/lime/src/github.com/quarnster/util/text/serialized_buffer.go:26 +0xc0

goroutine 175 [chan receive]:
github.com/quarnster/util/text.(*SerializedBuffer).worker(0xc2081029d8)
    /home/felix/devel/lime/src/github.com/quarnster/util/text/serialized_buffer.go:40 +0x89
created by github.com/quarnster/util/text.(*SerializedBuffer).init
    /home/felix/devel/lime/src/github.com/quarnster/util/text/serialized_buffer.go:26 +0xc0

goroutine 172 [chan receive]:
github.com/quarnster/util/text.(*SerializedBuffer).worker(0xc208102928)
    /home/felix/devel/lime/src/github.com/quarnster/util/text/serialized_buffer.go:40 +0x89
created by github.com/quarnster/util/text.(*SerializedBuffer).init
    /home/felix/devel/lime/src/github.com/quarnster/util/text/serialized_buffer.go:26 +0xc0

goroutine 306 [chan receive]:
github.com/quarnster/util/text.(*SerializedBuffer).worker(0xc2081ac668)
    /home/felix/devel/lime/src/github.com/quarnster/util/text/serialized_buffer.go:40 +0x89
created by github.com/quarnster/util/text.(*SerializedBuffer).init
    /home/felix/devel/lime/src/github.com/quarnster/util/text/serialized_buffer.go:26 +0xc0

goroutine 225 [syscall]:
runtime.goexit()
    /home/felix/.gvm/gos/go1.3.1/src/pkg/runtime/proc.c:1445

goroutine 307 [chan receive]:
github.com/limetext/lime/backend.(*View).parsethread(0xc2082da400)
    /home/felix/devel/lime/src/github.com/limetext/lime/backend/view.go:190 +0x1a8
created by github.com/limetext/lime/backend.newView
    /home/felix/devel/lime/src/github.com/limetext/lime/backend/view.go:69 +0x1fe

goroutine 310 [chan receive]:
github.com/limetext/lime/backend.(*View).parsethread(0xc2082da600)
    /home/felix/devel/lime/src/github.com/limetext/lime/backend/view.go:190 +0x1a8
created by github.com/limetext/lime/backend.newView
    /home/felix/devel/lime/src/github.com/limetext/lime/backend/view.go:69 +0x1fe

goroutine 308 [chan receive]:
github.com/quarnster/util/text.(*SerializedBuffer).worker(0xc2081ac7c8)
    /home/felix/devel/lime/src/github.com/quarnster/util/text/serialized_buffer.go:40 +0x89
created by github.com/quarnster/util/text.(*SerializedBuffer).init
    /home/felix/devel/lime/src/github.com/quarnster/util/text/serialized_buffer.go:26 +0xc0

goroutine 305 [chan receive]:
github.com/limetext/lime/backend.(*View).parsethread(0xc2082da200)
    /home/felix/devel/lime/src/github.com/limetext/lime/backend/view.go:190 +0x1a8
created by github.com/limetext/lime/backend.newView
    /home/felix/devel/lime/src/github.com/limetext/lime/backend/view.go:69 +0x1fe

goroutine 309 [runnable]:
regexp/syntax.(*Prog).Prefix(0xc2082e6930, 0xa0, 0x0, 0x0)
    /home/felix/.gvm/gos/go1.3.1/src/pkg/regexp/syntax/prog.go:149
regexp.compile(0x7c9370, 0x7, 0xd4, 0x7839b8, 0x0, 0x0)
    /home/felix/.gvm/gos/go1.3.1/src/pkg/regexp/regexp.go:175 +0x314
regexp.Compile(0x7c9370, 0x7, 0x19, 0x0, 0x0)
    /home/felix/.gvm/gos/go1.3.1/src/pkg/regexp/regexp.go:118 +0x5d
regexp.MustCompile(0x7c9370, 0x7, 0x0)
    /home/felix/.gvm/gos/go1.3.1/src/pkg/regexp/regexp.go:219 +0x50
github.com/limetext/lime/backend/util.PascalCaseToSnakeCase(0x7ced10, 0x7, 0x0, 0x0)
    /home/felix/devel/lime/src/github.com/limetext/lime/backend/util/case.go:13 +0x5a
github.com/limetext/lime/backend.(*commandHandler).init(0xc208056058, 0x7a3440, 0xc2080e1520, 0xc2082e68d0, 0x0, 0x0)
    /home/felix/devel/lime/src/github.com/limetext/lime/backend/commandhandler.go:60 +0x345
github.com/limetext/lime/backend.(*commandHandler).RunTextCommand(0xc208056058, 0xc2082da600, 0x7ed090, 0xe, 0xc2082e68d0, 0x0, 0x0)
    /home/felix/devel/lime/src/github.com/limetext/lime/backend/commandhandler.go:113 +0x3c3
github.com/limetext/lime/backend/commands.TestToggleSetting(0xc20821aea0)
    /home/felix/devel/lime/src/github.com/limetext/lime/backend/commands/settings_test.go:28 +0x42b
testing.tRunner(0xc20821aea0, 0xbb4360)
    /home/felix/.gvm/gos/go1.3.1/src/pkg/testing/testing.go:422 +0x110
created by testing.RunTests
    /home/felix/.gvm/gos/go1.3.1/src/pkg/testing/testing.go:504 +0xb46

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