* Add `--censor` switch for disabling source code display
Related to #1294
This currently only affects parse errors, but can later be extended
to type errors, too
* Fix type blindiness
... as requested by @sjakobi
* Replace `Bool` with `Censor`
* Replace `Maybe FilePath` with `Input`
* Remove most uses of `StandardVersion` from the API
We no longer support multiple versions of the standard, except for
supporting old integrity checks, so this change removes all inessential
uses of `StandardVersion` from the API and command-line interface.
* Fix `dhall-lsp-server` build
* Load imports recursively
This is the big change that enables us to implement 'semi-semantic'
caching.
* Use `throwM` instead of `liftIO . throwIO`
* Fix build with __GHCJS__
* Fix exceptions in Dhall.Import
* Fix dhall-lsp-server
* Revert exception behaviour on typecheck errors
This is one for a separate pull request!
* Make sure loadImportFresh returns alpha-normal expression
As caught by @Gabriel439, `loadImportFresh` violated the invariant that
`ImportSemantics` should be alpha-beta-normal. This fix also means that
we don't have to alpha-normalise again in `loadImportWithSemanticCache`.
* Remove old comment
* Fix regression test for issue 216
Turns out the test was testing the wrong thing, because it was
pretty-printing an import. This worked previously because when importing
uncached expressions we would not alpha-normalise them.
* Restore `dhall freeze` bevhaviour
Newly frozen imports should also be present in the cache.
* Fix misleading comment
* Add `Chained` type to capture fully chained imports
Until now we used `Import` two mean two different things:
- The syntactic construct; e.g. `./a.dhall` corresponds to the following
AST:
```
Embed
(Import
(ImportHashed Nothing (Local Here (Directory ["."]) "a.dhall"))
Code)
```
- The physical location the import is pointing to, computed by
'chaining' the syntactical import with the the 'physical' parent import.
For example the syntactic import `./a.dhall` might actually refer to the
remote file `http://host/directory/a.dhall`.
This commit adds a `Chained` newtype on top of `Import` to make this
distinction explicit at type level.
* Use `HTTPHeaders` alias for binary headers
I claim that `HTTPHeaders` is more readable and informative than the
unfolded type `(CI ByteString, ByteString)`.
* Typecheck and normalise http headers earlier
Previously we would typecheck and normalise http headers in
`exprFromImport`, i.e. while loading the import. This commit adds the
invariant that any headers in 'Chained' imports are already typechecked
and normalised, and moves this step into `loadWith` accordingly.
This causes a subtle difference in behaviour when importing remote files
with headers `as Location`: previously, nonsensical expressions like
`http://a using 0 0 as Location` were valid, while they would now cause
a type error.
* Fix dhall-lsp-server
* Fix Dhall.Import API regarding `Chained` imports
Do not expose the `Chained` constructor; we don't want external code
breaking our invariants! Also further clarifies the comment describing
the `Chained` type.
* Fix dhall-lsp-server
Since we are no longer able to construct `Chained` imports directly we
need to export a few additional helper functions from Dhall.Import.
Furthermore, since VSCode (and presumably the other editors out there
implementing the LSP protocol) does not support opening remote files
anyway we can get rid of some complications by dropping support for
remote files entirely on the back-end.
* Generalise decodeExpression, fixes TODO
* Fix tests
* Fix benchmarks
* Remove Travis cache for `~/.local/bin`
* Fix copy-pasted comment
Thanks to @Gabriel439 for spotting this!
* Add clarifying comment to `toHeaders`
Part of https://github.com/dhall-lang/dhall-lang/issues/563
This flag freezes imports in the same way as the Prelude by providing a
fallback unprotected import without an integrity check. The primary use
case for this is caching imports with a graceful fallback, which is why
the flag is named `--cache`
The motivation behind this change is so that users can freeze remote imports
(like the Prelude) but ignore local imports so that subsequent runs of the
interpreter reflect changes to local files and environment variables.
The reasoning behind this is that there are two primary benefits of integrity
checks:
* Improved security
* Caching
... and one downside which is that updates to those imports are not pulled in
until the integrity check is updated or removed.
However, environment variables and local file paths do not benefit from
improved security or caching, so there is only a downside to freezing them.
Specifically:
* Environment variables and local file paths are both cheap to resolve
... so they don't really benefit from caching.
To be precise, they *could* benefit from caching if the cache expression is
cheaper to parse and normalize compared to the original file. For those
cases there is still an `--all` flag to freeze all imports.
* Environment variables and local file paths are trusted
For example, when a user runs the `dhall` executable they are implicitly
trusting their filesystem which provides that executable. Similarly, when
they run `dhall` without an absolute path they are implicitly trusting that
their `PATH` environment variable has not been compromised to point to a
malicious executable.
Up until now, Dhall's threat model has always been that local imports are
trusted but remote imports are not, so this is consistent with that threat
model.
... so as far as environment variables and local files are concerned there are
only downsides to freezing them and no up-side. This is why this change
no longer freezes them.
This also renames `hashImport` to `freezeImport` for more terminology
consistency.
The motivation for this change is:
* To catch build failures in downstream packages whenever we make a breaking
change to the `dhall` API
* To reduce the amount of work I need in order to cut a release for all of
these packages
* To better share Nix/CI-related logic between the projects
Note that I have not yet migrated `dhall-nix` in. I'm waiting for
https://github.com/dhall-lang/dhall-nix/issues/17 to be fixed since
`dhall-nix` is incompatible with later versions of `megaparsec` due to
`hnix`.
