Chrome Debugging Protocol: HeapProfiler.getHeapSnapshot Ignores Callback
google-chrome-devtools, google-chrome-extension, heap-memory, javascript
Solution
It is a bug in DevTools. I've filled an issue in chrome bug tracker.
Fortunately there is a workaround. You have to enable Debugger agent before getting the snapshot.
chrome.debugger.sendCommand(debuggeeId,"Debugger.enable", { }, function() { });
Three other commands were also affected by this bug.
Profiler.start
Profiler.stop
Profiler.getCPUProfile
Problem
I'm working on a testing suite (implemented as a Chrome extension) that programmatically takes and analyzes heap snapshots with Chrome/Chromium's remote debugging protocol. Because `Profiler.*` doesn't seem to be part of the public protocol, I'm using this page for reference. Right now, I'm able to take a heap snapshot by calling `HeapProfiler.takeHeapSnapshot` like in the snippet below. However, when I try calling `HeapProfiler.getHeapSnapshot`, my callback is completely ignored. ``` var debuggerId = {tabId: sender.tab.id}; chrome.debugger.attach(debuggerId, "1.0", function() { var listener = function(source, method, params) { if(source.tabId === debuggerId.tabId) { if(method === "HeapProfiler.addProfileHeader") { var uid = params.header.uid; chrome.debugger.sendCommand(debuggerId, "HeapProfiler.getHeapSnapshot", { uid: uid }, function() { console.log("I never get called!"); }); chrome.debugger.onEvent.removeListener(listener); } } }; chrome.debugger.onEvent.addListener(listener); chrome.debugger.sendCommand(debuggerId, "HeapProfiler.takeHeapSnapshot", { reportProgress: false }, function() { if(chrome.runtime.lastError) { console.error(chrome.runtime.lastError); } }); }); ```