It sounds like you would likely be able to troubleshoot the issue faster by reaching out to the React community.
If you are not planning on referencing the variable you could always use a const and that way it shouldn't be able to be set to `null` without throwing an error. If you are using React/Redux I would suggest looking at your reducers. I experienced slimier issues in the past. On Thursday, October 4, 2018 at 5:33:28 AM UTC-7, eloy.d...@gmail.com wrote: > > Hmm, that makes sense. Is there an internal object reference I can use > that does stay stable? > > And sorry if this wasn't clear from my message, but as I know nothing yet > of v8 do you have any pointers to the source where assignment occurs? > > On Thursday, October 4, 2018 at 2:28:42 PM UTC+2, Yang Guo wrote: >> >> Unfortunately this won't work 100% of the time. V8's GC may move objects, >> so the address you would need to watch is not fixed. >> >> Yang >> >> On Thu, Oct 4, 2018 at 2:25 PM <eloy.d...@gmail.com> wrote: >> >>> Hi, >>> >>> I’m completely new to v8, so bare with me. Because the node debugging >>> facility lacks the ability to define watchpoints (i.e. break when a >>> variable changes), I was thinking that maybe I could do so at the VM level >>> using lldb/gdb. >>> >>> The code I’m trying to debug tries to access a global variable, which >>> somewhere during execution gets set to `null`. A pseudo example looks like: >>> >>> ``` >>> var doc = document >>> debugger // <- here the object is a non-null value as expected >>> // Enzyme (a React testing utility) renders an async React tree and >>> somewhere during that period `document` gets set to `null` >>> mount(<SomeComponentThatDoesAsyncRendering />) // <- an exception is >>> raised because `document` is `null` >>> ``` >>> >>> My thinking is: >>> >>> 1. I use node/v8’s JS debugger to hit a breakpoint where I know the >>> variable is what I expect it to be >>> 2. break using lldb/gdb, find the JS variable >>> 3. set a native watchpoint or a conditional breakpoint on the VM code >>> that assigns variables for the address of the JS variable >>> 4. when the native breakpoint hits, get a JS execution stack trace to >>> find the location that is assigning the new (`null`) value >>> >>> Does this make any sense? >>> >>> Cheers, >>> Eloy >>> >>> -- >>> -- >>> v8-dev mailing list >>> v8-...@googlegroups.com >>> http://groups.google.com/group/v8-dev >>> --- >>> You received this message because you are subscribed to the Google >>> Groups "v8-dev" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to v8-dev+un...@googlegroups.com. >>> For more options, visit https://groups.google.com/d/optout. >>> >> -- -- v8-dev mailing list v8-dev@googlegroups.com http://groups.google.com/group/v8-dev --- You received this message because you are subscribed to the Google Groups "v8-dev" group. To unsubscribe from this group and stop receiving emails from it, send an email to v8-dev+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
