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When I build this package with the mtl-2.3 release I get this failure:

src/Data/Aeson/Commit.hs:64:40: error:
    Not in scope: type constructor or class ‘ExceptT’
   |
64 | newtype Commit a = Commit {unCommit :: ExceptT [Parser Void] Parser a}
   |                                        ^^^^^^^

This build failure is due to haskell/mtl#117 which will be fixed in a follow-up release of mtl.

Building with a version of mtl that includes a fix to that issue, I'm getting

src/Data/Aeson/Commit.hs:73:3: error:
    Variable not in scope:
      lift :: Parser b -> ExceptT [Parser Void] Parser b
   |
73 |   lift $ post a
   |   ^^^^

• fix cabal category
• add source repo links
• there was some issue in a doc that I forgot about
• add to stack
• sensible export order, the actual definition of Commit doesn't really matter

Now that we require newer Aeson versions, aeson-commit doesn't build cleanly on nix. Add nix code to handle getting the correct versions of Aeson and its dependencies

The aeson library has the concept of a JSONPath that is shown on parse errors like

Error in $.posts[0].comments[2]: <error text>

These JSONPaths are discarded when parsing using Commit, so while the backtracking is limited to output the error message at the relevant point, the error messages are still quite uninformative if the source JSON is large.

The tests are out of phase with the code