Strange behavior with invalid snapshot passed to `stack new`

[sjshuck]

Stack version: 3.9.1

I ran

stack new --snapshot lts.24.26 blah

Note that the first . should have been a -. It quietly created a new Stack project without a stack.yaml. After going inside and running stack build, it gave the standard "Perhaps you need to run stack init?" error.

Not sure what the desired behavior is here but it probably shouldn't be that.

[mpilgrem]

@sjshuck, thanks for reporting. On Windows 11, with Stack 3.9.1, in directory D:\Users\mike\Code\Haskell, I have:

❯ stack new --snapshot lts.24.26 blah
Using content of GH_TOKEN environment variable to authenticate GitHub REST
API.
Downloading template new-template to create project blah in directory
blah\...
Downloaded D:\sr\templates\new-template.hsfiles.
Looking for Cabal or package.yaml files to use to initialise Stack's
project-level YAML configuration file.

Using the Cabal packages:
* blah\


Error: [S-775]
       Exception while reading snapshot from lts.24.26:

       YAML exception:
       Yaml file not found: D:\Users\mike\Code\Haskell\lts.24.26
       HasCallStack backtrace:
         collectBacktraces, called at libraries\ghc-internal\src\GHC\Internal\Exception.hs:169:13 in ghc-internal:GHC.Internal.Exception
         toExceptionWithBacktrace, called at libraries\ghc-internal\src\GHC\Internal\IO.hs:260:11 in ghc-internal:GHC.Internal.IO
         throwIO, called at src\Data\Yaml.hs:274:60 in yaml-0.11.11.2-E1frnYWViU6Hr3koaywJTZ:Data.Yaml

The HasCallStack backtrace 'noise' in error S-775 is a GHC 9.10 'glitch' (#6840).

That aside, as lts.24.26 is not in the format of a (a) compiler-only snapshot, (b) convenience synonym, or (c) URL it is interpreted as (d) a local file name. Stack correctly reports that file cannot be found. See:

• https://docs.haskellstack.org/en/stable/topics/snapshot_location/

I think there is scope to improve the online documentation.

[sjshuck]

For some reason I can't reproduce the original behavior I observed. I now have identical output to what you are showing. Originally, I had no output at all; the command succeeded. Perhaps I misreported the issue; it wouldn't be the first time and I suspect it won't be the last either.

In any case thanks for the response.