Pkg.jl: Pinning a pinned package should error instead of be a no-op

[fredrikekre]

(v1.1) pkg> st
    Status `~/.julia/environments/v1.1/Project.toml`
  [7876af07] Example v0.5.1

(v1.1) pkg> pin [email protected]
 Resolving package versions...
  Updating `~/.julia/environments/v1.1/Project.toml`
  [7876af07] ↓ Example v0.5.1 ⇒ v0.4.1 ⚲
  Updating `~/.julia/environments/v1.1/Manifest.toml`
  [7876af07] ↓ Example v0.5.1 ⇒ v0.4.1 ⚲
[...]

(v1.1) pkg> pin [email protected]                               <-- This should error ?
 Resolving package versions...
  Updating `~/.julia/environments/v1.1/Project.toml`
 [no changes]
  Updating `~/.julia/environments/v1.1/Manifest.toml`
 [no changes]

[fredrikekre]

Or maybe actually pin to the new version, would mean that pin implicitly frees though.

[StefanKarpinski]

The two sensible behaviors would seem to be:

1. Tell you that it's already pinned and that you have to free and then pin again.
2. Do that for you automatically with a warning.

[00vareladavid]

I vote for an informative warning. If that is insufficient, possibly introduce a --force option to pin?

[00vareladavid]

pin should also not work on packages which have already been deved. It doesn't make sense to pin something which is already considered fixed.