Common Errors

Unknown syntactical constructs #

ERROR: encountered unknown syntactical constructs:
HsSpliceE{}

Brittany (as of v0.11.0.0) doesn’t handle Template Haskell (among other things), and generates the above error when it sees it. The solution is to ignore the offending files.

---
- brittany:
    include:
      - "**/*.hs"
      - "!src/MyBadFile.hs"

Alternative, you can disable the offending expression in the Haskell source

-- brittany-disable-next-binding

someFunction =
  [someQuote|
    someText
  |]

-- brittany-disable-next-binding

someOtherFunction =
  $(someOtherQuote "someText")

Note that disable-next-binding on works on top-level bindings. Attractive as it may be, you can’t disable a specific binding within a where or let.

Restyled keeps removing shebangs #

If you edit a “Stack Script” , you will find that Restyled (through Brittany) really wants to strip that shebang.

This is an open issue: https://github.com/lspitzner/brittany/issues/192

Unfortunately, you must exclude such files via .restyled.yaml.

parse error on input … #

If the HLint restyler fails, and a message like the following is visible:

refactor: (RealSrcSpan SrcSpanOneLine "./src/Something.hs" 12 33 34,"parse error on input \8216@\8217")
CallStack (from HasCallStack):
  error, called at src/Refact/Run.hs:190:22 in main:Refact.Run

This is because the module contains TypeApplications , which apply-refact can’t handle.

Unfortunately, the only workaround is to exclude the file from Restyler .

Cannot find module ‘@…’ #

This happens when you import a module from a 3rd party package that provides some plugin or shared rules or configuration. Such plugins are not installed in the environment where Restyled runs prettier. You can find the list of packages we pre-install in the Restyler’s package.json .

For security reasons, Restylers are run in a restricted environment. Part of this restriction is no networking; this means 3rd party tools cannot be installed on demand and anything your project needs must be repository-local or come pre-installed in the Restyler image.

We are happy to accept PRs that add popular, project-agnostic packages to the Restyler image. If you are attempting to use such a package, please open a PR on restyled.io/restylers .

Restyled also supports custom Restyler images , in which you can install whatever software you like.

“prettier-with-tailwindcss”: executable file not found in $PATH #

We recently added a new executable to the prettier restyler to support tailwindcss users. This mean modifying the manifests such that that command is used. Provided you’re using a recent enough restyled/restyler-prettier image, that’s all fine.

However, some users may have configured a specific version of that image, for example:

restylers:
  - prettier:
      image: restyled/restyler-prettier:v1.19.1-2
  - "*"

That will cause the error because the older images don’t have that executable. To workaround this, configure command back to its original value at the time this older image was in use:

restylers:
  - prettier:
      image: restyled/restyler-prettier:v1.19.1-2
      command:
        - prettier
        - --write
  - "*"

Did you intend to specify a full Restyler object… #

TL;DR: you may have incorrect indentation.

restylers values are expected to be a “named override”:

# Exhibit A
restylers:
  - prettier: # <-- key: the name of a known Restyler
      include: # <-- value: an object overriding some of its properties
        - "**/*.jsx"

But we also support fully specifying a Restyler directly:

# Exhibit B
restylers:
  - name: prettier # <-- element: flat, complete Restyler object
    image: restyled/restyler-prettier
    command: [prettier]
    arguments: [--inplace]
    include: [...]
    # more keys...

Normally, this feature is only known to Restyled contributors who may use it to try out custom Restylers or non-default features not directly supported in the named-override syntax. The problem is it’s super easy to accidentally do this:

restylers:
  - prettier:
    include:
      - "**/*.jsx"

Notice how you meant to do Exhibit A, but this will parse like Exhibit B. The error that results could be confusing because it will talk about prettier being an invalid key for a Restyler (it is), when the real problem is that include needs to be shifted over two characters.

The solution is to make sure your indentation is like Exhibit A, assuming that’s what you meant.

Mapping values are not allowed in this context #

This error basically means you’ve started to define an Object (key-values) in a place where that’s not expected or allowed by the Yaml syntax. The most common reason for this is when you take a configuration naming Restylers as String names:

restylers:
  - brittany

And start treating them as the key into a configuration Object,

restylers:
  - brittany
      include:
        - "**/*.hs"
        - "!src/BadFile.hs"

This is invalid because you’ve not changed the String name into a key,

restylers:
  - brittany: # <- missing ":"
      include:
        - "**/*.hs"
        - "!src/BadFile.hs"

If you pay careful attention to the syntax highlighting differences in these two examples, that can help spot such problems.

For more details see the Configuration Reference .

Restyle Error 128 #

This means the configured command is not available as an executable on $PATH within then restyler image.

There are two common reasons for this:

1- We’ve updated the restyler to use a new command not present in older images #

Sometimes we need to create and use new executables as a restyler evolves. We will then update the current version of our “manifest” to indicate using that as the default command. If you’re using an older image that lacks that executable, you will see this error. The solution is to explicitly configure command to what it was before, when that image was in use.

2- You’ve configured an invalid command yourself #

If you’ve configured command for this restyler, that is where the issue is. It is either misspelled or points to a non-existent, or not-on-$PATH executable. Note that command is a list option, to support supplying initial arguments. If not a list, it’s expected to not be setting arguments and is turned into a single-element list.

# This is fine
restylers:
  - prettier:
      command: prettier

# But this is wrong; it's being treated as a single file named `prettier\ --write`
restylers:
  - prettier:
      command: prettier --write

# This is correct
restylers:
  - prettier:
      command:
        - prettier
        - --write

# And so is this
restylers:
  - prettier:
      command: [prettier, --write]

rustfmt may have failed to format #

Restyled can fail with this error:

error: left behind trailing whitespace
    --> /code/src/lib.rs:1058
     |
1058 |         //
     |           ^

warning: rustfmt may have failed to format. See previous 1 errors.

This is an open rustfmt bug: https://github.com/rust-lang/rustfmt/issues/2916 .

Once rustfmt has been fixed, Restyled can update. For now, unfortunately, you have to either edit the code in a way that doesn’t cause this bug, or exclude it from Restyled via .restyled.yaml.

expected one of …, or an operator, found keyword move #

The rustfmt Restyler is built to run the 2015 “edition”*, and constructions only available in the 2018 edition may cause such syntax errors.

The fix is to specify your edition via arguments:

restylers:
  - rustfmt:
      arguments:
        - "--edition"
        - "2018"

Or by creating a rustfmt.toml for the project:

edition = "2018"

FailedToFormat “failed to download” #

       org.scalafmt.cli.FailedToFormat: /code/.scalafmt.conf
       Caused by: org.scalafmt.interfaces.ScalafmtException: [...] failed to download

If the version of scalafmt doesn’t match the version key in .scalafmt.conf, it will dynamically download the correct version. This behavior cannot be disabled. We don’t allow restylers to make network requests, so that attempt fails with the above error.

You can either change your version configuration to match our image, or use a different image that is the correct version through a Restyler Override . You can see what images are available on on Docker Hub .

Restyled keeps removing ViewPatterns #

See jaspervdj/stylish-haskell#75 for details. Most likely, you’ll want to disable the remove_redundant feature in your .stylish-haskell.yaml.