This isn't depot_tools. install-sysroot.py is one of chromium's hooks[1]. So while the complaint that an undocumented dependency on curl exists is valid, it needs to be taken up with the owners[2] of that script. Assigning to sbc@, who seems to be the de-facto owner of it.

[1] https://chromium.googlesource.com/chromium/src/+/9f7c5f271a7c493f3b1fe2c16dedad70686654c6/DEPS#583
[2] https://chromium.googlesource.com/chromium/src/+/9f7c5f271a7c493f3b1fe2c16dedad70686654c6/build/linux/OWNERS
[3] https://chromium.googlesource.com/chromium/src/+blame/9f7c5f271a7c493f3b1fe2c16dedad70686654c6/build/linux/sysroot_scripts/install-sysroot.py

Had this issue as well on a brand new Ubuntu 16.04 install. Stacktrace was extremely unhelpful. Should at least throw some sort of helpful exception.

I think the problem here is that the initial fetch shouldn't run hooks, but the docs (http://dev.chromium.org/developers/how-tos/get-the-code) don't indicate that.

It's expected that there might be dependency issues, hence the instructions to run 'install-build-deps.sh' (which installs curl) right after the first fetch. It seems wrong that those instructions talk about running 'gclient runhooks', which seems to imply that hooks wouldn't already have been run, but it doesn't say to use 'fetch --nohooks', to prevent the (possibly broken) hooks from running in the first place.

Duplicate of  bug 650482 ?