This patch remembers the paths of expanded scope items (including sub-objects) in the debugger's reducer and uses those to re-expand the same paths after unpausing and pausing somewhere else. The main limitation of this is that when stepping from one scope to another the paths will be collapsed again, even for variables that are still in scope. This could be improved some more but seems a good place to work from for now. Unfortunately this patch isn't ready for review because changes are needed to the Tree and ObjectInspector components of the devtools-reps repo, which is hosted on github instead of m-c.

Hmm, the devtools-reps repo no longer exists (and the README in m-c is out of date). ObjectInspector is in the firefox-devtools component but Tree does not seem to be. I don't know how to get these changes landed.

(In reply to Brian Hackett (:bhackett) from comment #6)

changes are needed to the Tree and ObjectInspector components of the devtools-reps repo, which is hosted on github instead of m-c.

I think you can just land the changes in m-c and darkwing will export the changes to github.

But you shouldn't edit devtools/client/shared/components/reps/reps.js directly, instead change devtools/client/debugger/packages/devtools-components/src/tree.js and devtools/client/debugger/packages/devtools-reps/src/object-inspector/components/ObjectInspector.js.

Then use cd devtools/client/debugger && npm install && node bin/bundle.js to generate the reps.js

Yep - i second oriol's advice. I also second your approach, this is exactly what I was planning on doing.

Thanks for the help Oriol, the patch above modifies the package files and includes the corresponding reps.js changes as well.

Backed out 3 changesets (bug 1556847, bug 1556858, bug 1405402) for eslint failures at /actors/replay/debugger.js on a CLOSED TREE.

Backout link: https://hg.mozilla.org/integration/mozilla-inbound/rev/756e8d09a98ff8869a8065337e1f2d2f9816e126

Pushes with failures:
https://treeherder.mozilla.org/#/jobs?repo=mozilla-inbound&resultStatus=testfailed%2Cbusted%2Cexception&revision=1bf0b6a8dd1309ee22bd5b3593ca150172b644a9&selectedJob=257596995

https://treeherder.mozilla.org/#/jobs?repo=mozilla-inbound&resultStatus=testfailed%2Cbusted%2Cexception&revision=099de68d4716a2c7ba843c5cfcf053bd25fcf91c&selectedJob=257597102

https://treeherder.mozilla.org/#/jobs?repo=mozilla-inbound&resultStatus=testfailed%2Cbusted%2Cexception&revision=03df8624c36c9434ab73dcd8c118563310e81c85&selectedJob=257597123

Log link: https://treeherder.mozilla.org/logviewer.html#/jobs?job_id=257596995&repo=mozilla-inbound&lineNumber=290

Log snippet:
[task 2019-07-21T18:16:52.027Z] copying build/lib.linux-x86_64-2.7/psutil/_psutil_linux.so -> psutil
[task 2019-07-21T18:16:52.027Z] copying build/lib.linux-x86_64-2.7/psutil/_psutil_posix.so -> psutil
[task 2019-07-21T18:16:52.027Z]
[task 2019-07-21T18:16:52.027Z] Error processing command. Ignoring because optional. (optional:packages.txt:comm/build/virtualenv_packages.txt)
[task 2019-07-21T18:33:27.238Z] TEST-UNEXPECTED-ERROR | /builds/worker/checkouts/gecko/devtools/server/actors/replay/debugger.js:548:28 | Insert ??????? (prettier/prettier)
[task 2019-07-21T18:33:27.238Z] TEST-UNEXPECTED-ERROR | /builds/worker/checkouts/gecko/devtools/server/actors/replay/debugger.js:549:7 | Replace type:?"getSource", with ??type:?"getSource",???????? (prettier/prettier)
[task 2019-07-21T18:33:27.238Z] TEST-UNEXPECTED-ERROR | /builds/worker/checkouts/gecko/devtools/server/actors/replay/debugger.js:550:1 | Replace ????}) with ??????})????? (prettier/prettier)
[taskcluster 2019-07-21 18:33:27.578Z] === Task Finished ===
[taskcluster 2019-07-21 18:33:28.586Z] Unsuccessful task run with exit code: 1 completed in 1368.153 seconds

https://hg.mozilla.org/mozilla-central/rev/46499a50b778