if you install a version of snapcraft via try mode, i.e. `snap try --classic squashfs-root` for an unpacked snapcraft snap, it fails to run because it can't download the snapcraft snap file: ``` 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. Waiting for network to be ready... 2020-08-21T16:56:10Z INFO Waiting for automatic snapd restart... core 16-2.45.3.1 from Canonical✓ installed "core" switched to the "latest/stable" channel core18 20200807 from Canonical✓ installed "core18" switched to the "latest/edge" channel Sorry, an error occurred in Snapcraft: 400 Client Error: Bad Request for url: http+unix://%2Frun%2Fsnapd.socket/v2/snaps/snapcraft/file We would appreciate it if you anonymously reported this issue. No other data than the traceback and the version of snapcraft in use will be sent. Would you like to send this error data? (Yes/No/Always/View) [no]: yes Thank you, sent. You can find the traceback in file '/tmp/tmpn2l6zob_/trace.txt'. ``` Traceback (most recent call last): File "/snap/snapcraft/x1/bin/snapcraft", line 33, in <module> sys.exit(load_entry_point('snapcraft==4.1.5.post12+gitfbd93aaa', 'console_scripts', 'snapcraft')()) File "/snap/snapcraft/x1/lib/python3.6/site-packages/click/core.py", line 829, in __call__ return self.main(*args, **kwargs) File "/snap/snapcraft/x1/lib/python3.6/site-packages/click/core.py", line 782, in main rv = self.invoke(ctx) File "/snap/snapcraft/x1/lib/python3.6/site-packages/click/core.py", line 1236, in invoke return Command.invoke(self, ctx) File "/snap/snapcraft/x1/lib/python3.6/site-packages/click/core.py", line 1066, in invoke return ctx.invoke(self.callback, **ctx.params) File "/snap/snapcraft/x1/lib/python3.6/site-packages/click/core.py", line 610, in invoke return callback(*args, **kwargs) File "/snap/snapcraft/x1/lib/python3.6/site-packages/click/decorators.py", line 21, in new_func return f(get_current_context(), *args, **kwargs) File "/snap/snapcraft/x1/lib/python3.6/site-packages/snapcraft/cli/_runner.py", line 132, in run snap_command.invoke(ctx) File "/snap/snapcraft/x1/lib/python3.6/site-packages/snapcraft/cli/_command.py", line 88, in invoke return super().invoke(ctx) File "/snap/snapcraft/x1/lib/python3.6/site-packages/click/core.py", line 1066, in invoke return ctx.invoke(self.callback, **ctx.params) File "/snap/snapcraft/x1/lib/python3.6/site-packages/click/core.py", line 610, in invoke return callback(*args, **kwargs) File "/snap/snapcraft/x1/lib/python3.6/site-packages/snapcraft/cli/lifecycle.py", line 354, in snap _execute(steps.PRIME, parts=tuple(), pack_project=True, output=output, **kwargs) File "/snap/snapcraft/x1/lib/python3.6/site-packages/snapcraft/cli/lifecycle.py", line 116, in _execute project=project, echoer=echo, build_provider_flags=build_provider_flags File "/snap/snapcraft/x1/lib/python3.6/site-packages/snapcraft/internal/build_providers/_base_provider.py", line 87, in __enter__ self.create() File "/snap/snapcraft/x1/lib/python3.6/site-packages/snapcraft/internal/build_providers/_lxd/_lxd.py", line 284, in create self.launch_instance() File "/snap/snapcraft/x1/lib/python3.6/site-packages/snapcraft/internal/build_providers/_base_provider.py", line 259, in launch_instance self._setup_snapcraft() File "/snap/snapcraft/x1/lib/python3.6/site-packages/snapcraft/internal/build_providers/_lxd/_lxd.py", line 470, in _setup_snapcraft super()._setup_snapcraft() File "/snap/snapcraft/x1/lib/python3.6/site-packages/snapcraft/internal/build_providers/_base_provider.py", line 470, in _setup_snapcraft snap_injector.apply() File "/snap/snapcraft/x1/lib/python3.6/site-packages/snapcraft/internal/build_providers/_snap.py", line 394, in apply snap.push_host_snap(file_pusher=self._file_pusher) File "/snap/snapcraft/x1/lib/python3.6/site-packages/snapcraft/internal/build_providers/_snap.py", line 141, in push_host_snap snap_path=snap_file_path, assertion_path=assertion_file_path File "/snap/snapcraft/x1/lib/python3.6/site-packages/snapcraft/internal/repo/snaps.py", line 198, in local_download snap_file_iter = _get_local_snap_file_iter(self.name, chunk_size=1024) File "/snap/snapcraft/x1/lib/python3.6/site-packages/snapcraft/internal/repo/snaps.py", line 373, in _get_local_snap_file_iter snap_file.raise_for_status() File "/snap/snapcraft/x1/lib/python3.6/site-packages/requests/models.py", line 940, in raise_for_status raise HTTPError(http_error_msg, response=self) requests.exceptions.HTTPError: 400 Client Error: Bad Request for url: http+unix://%2Frun%2Fsnapd.socket/v2/snaps/snapcraft/file This is expected as you cannot download the snap file for a try mode snap: https://github.com/snapcore/snapd/blob/f964a2817cbc0a61aface6104768b6a80c00a2ca/daemon/api_snap_file.go#L63-L65