Command Line Quickstart

Sorbet has a wealth of command line options; we’ll only be covering a subset of them here. See the Command Line Reference for the full set of available options, or check the help at the command line:

# to learn about available srb subcommands
❯ srb --help

# for options that Sorbet uses when typechecking
❯ srb tc --help

In this doc, we’ll cover only the command line interface to the srb tc subcommand. For information about tapioca and srb rbi, see RBI files.

Config file

The first time tapioca init runs, it creates a config file that srb tc will read, located at sorbet/config. The config file is actually just a newline-separated list of arguments to pass to srb tc, the same as if they’d been passed at the command line.

--dir
.
# Full-line comment
--ignore
path/to/ignore.rb

Every line in this file acts as if it’s prepended to the argument list of srb tc. So arguments in the config file are always passed first (if it exists), followed by arguments provided on the command line.

For a full description of the config file format, see the output of srb tc --help.

To skip loading the config file (i.e., to create minimal repro examples to report an issue), there’s the --no-config flag:

srb tc --no-config ...

This makes it so that the only args Sorbet reads are those explicitly passed on the command line.

Next we’ll call out some specific flags that are likely to help troubleshoot problems or adapt Sorbet into an existing project.

Including and excluding files

First, some examples:

# All *.rb / *.rbi files in the current folder
srb tc .

# Only the file foo.rb (+ any paths mentioned in sorbet/config)
srb tc foo.rb

# All *.rb / *.rbi files in the current folder,
# minus any file in the vendor folder of the current directory.
srb tc . --ignore=/vendor

srb tc can be given a list of paths (either folder or files) to Ruby files that it should read. By default, sorbet/config is created to contain ., so srb tc will type check every file in the current directory^[1].

Note: Sorbet only checks files that end in *.rb or *.rbi. To check other files, they must be explicitly named on the command line (or in the config file), or given an appropriate file extension.

Sometimes, including an entire folder includes too many files. We can refine the list of files Sorbet reads with the --ignore flag. The syntax is:

--ignore <pattern>

This will ignore input files that contain the given pattern in their paths (relative to the input path passed to Sorbet). Patterns beginning with / match against the prefix of these relative paths; others are substring matches. Matches must be against whole component parts, so foo matches /foo/bar.rb and /bar/foo/baz.rb but not /foo.rb or /foo2/bar.rb.

Accepting autocorrect suggestions

For certain errors, Sorbet suggests autocorrects that can be accepted to automatically fix those errors. For example:

sig {params(xs: T::Array[Integer]).void}
def example(xs)
  xs[0] + 1 # error: Method `+` does not exist on `NilClass` component
end

example([1, 2, 3])

→ View on sorbet.run

In this example, Sorbet does not think that the + method always exists, because xs[0] might be nil if the xs list is empty.

In this example, though, we know that the xs array will always be non-empty. If, as the programmer, we know this invariant will always hold, we can use T.must to fix the problem. Sorbet even suggests that in the error message:

editor.rb:6: Method `+` does not exist on `NilClass` component of `T.nilable(Integer)` https://srb.help/7003
     6 |  xs[0] + 1
                ^
  Got `T.nilable(Integer)` originating from:
    editor.rb:6:
     6 |  xs[0] + 1
          ^^^^^
  Autocorrect: Use `-a` to autocorrect
    editor.rb:6: Replace with `T.must(xs[0])`
     6 |  xs[0] + 1
          ^^^^^
Errors: 1

To accept this suggestion, we can re-run Sorbet with the -a or --autocorrect command line flag:

❯ srb tc --autocorrect

Limiting autocorrect suggestions

By default, Sorbet will apply all autocorrect suggestions when the -a or --autocorrect flag is provided. To only have Sorbet apply some autocorrect suggestions, use the --isolate-error-code flag with a Sorbet error code. For example, using the error code in the above error message:

❯ srb tc --autocorrect --isolate-error-code=7003

The --isolate-error-code option can be repeated with different error codes to have Sorbet apply autocorrects for all the mentioned error codes, but no others.

There is no way to have Sorbet only apply autocorrect suggestions in a given file. Instead, use a version control system to undo autocorrect changes Sorbet makes in files that should not be changed.

Sometimes, Sorbet autocorrects include suggestions to rename a method, for example to fix a supposed typo. Sometimes these “did you mean” suggestions can accidentally change the meaning of a program. To disable these did you mean suggestions, use --did-you-mean=false:

❯ srb tc --autocorrect --did-you-mean=false

Silencing errors in bulk

Sometimes, Sorbet doesn’t know how to fix an error, it only knows how to silence the error. Sorbet does not show these autocorrect suggestions by default, because it does not want to train people, especially new Sorbet users, to blindly silence type errors.

However, there are cases where silencing errors in bulk can be useful (e.g., when doing a large-but-incremental refactor to a core library, or upgrading to a new Sorbet version that introduces many new type errors).

Use the --suggest-unsafe flag to have Sorbet additionally produce autocorrect suggestions that will unconditionally silence certain errors. Use --suggest-unsafe --autocorrect to accept these suggestions. For example, here is a program that Sorbet would not usually suggest an autocorrect for:

sig {params(x: T.any(Integer, String)).void}
def example(x)
  1 + x # error: Expected `Integer` but found `T.any(Integer, String)`
end

example(1)

But if we pass the --suggest-unsafe flag to Sorbet, it will suggest an autocorrect:

❯ srb tc --suggest-unsafe
editor.rb:6: Expected `Integer` but found `T.any(Integer, String)` for argument `arg0` https://srb.help/7002
     6 |  1 + x
              ^
  Expected `Integer` for argument `arg0` of method `Integer#+`:
    https://github.com/sorbet/sorbet/tree/master/rbi/core/integer.rbi#L148:
     148 |        arg0: Integer,
                  ^^^^
  Got `T.any(Integer, String)` originating from:
    editor.rb:5:
     5 |def example(x)
                    ^
  Autocorrect: Use `-a` to autocorrect
    editor.rb:6: Replace with `T.unsafe(x)`
     6 |  1 + x
              ^
Errors: 1

→ View without --suggest-unsafe on sorbet.run
→ View with --suggest-unsafe on sorbet.run

Note how the autocorrect suggestion here suggests adding T.unsafe, but only when the --suggest-unsafe flag was provided.

We recommend using --suggest-unsafe especially when doing Sorbet version upgrades. Usually the reason why a Sorbet version upgrade introduces a new error is because some old behavior was silently hiding a type error that was already present in the codebase. Using T.unsafe to silence the existing errors makes it easy to quickly upgrade to the new version, effectively locking newly-written code from suffering from that Sorbet bug. It’s always possible to audit old usages of T.unsafe. Sorbet gets better with each release, and upgrading Sorbet early and often is usually less work over time.

Sorbet also allows customizing the unsafe suggestions: given --suggest-unsafe=<custom method>, Sorbet will use the <custom method> in place of T.unsafe in all suggestions. For example:

❯ srb tc --suggest-unsafe=XXX.sorbet_0_5_1234 --autocorrect

This would cause case Sorbet to suggest converting x in the example above to XXX.sorbet_0_5_1234(x). It would then be possible to define a module like this:

module XXX
  # Automatically-suppressed error during upgrade to Sorbet version 0.5.1234
  #
  # If you see this method used in a file your team owns, consider removing the
  # call and fixing the resulting error, or replacing it with `T.unsafe` if the
  # error cannot be fixed.
  def self.sorbet_0_5_1234(x); x; end
end

A method named like this sticks out in the codebase as a flag to potential developers that something has been automatically silenced instead of being manually silenced. Placing a comment on the method shows the contextual message when people hover over any call site.

Overriding strictness levels

By default, Sorbet reads each file to determine its strictness level, defaulting to # typed: false if none is provided.

It can be useful, especially when Adopting Sorbet to see what it would be like if certain files were at a different strictness level. There are a handful of flags that do this:

`--typed <level>`

This option forces every file Sorbet reads to # typed: <level>. For example:

❯ srb tc --typed=true

Will report errors in every file as if they’d been declared # typed: true.

`--typed-override filepath.yaml`

This option is similar, except we can provide a YAML file that declares overrides on a file-by-file basis. For example, with this YAML file:

# -- foo.yaml --
true:
  - ./foo.rb

and this Ruby file:

# -- foo.rb --
# typed: false
"string" + :symbol

This will be the output using the --typed-override flag:

❯ srb tc --typed-override=foo.yaml foo.rb
foo.rb:3: Expected `String` but found `Symbol(:"symbol")` for argument `arg0`
...

`--cache-dir`: Caching parse results

Sorbet can cache the result of parsing files. If only a few files change between consecutive runs of Sorbet, Sorbet can skip substantial amounts of work creating abstract syntax trees from files, which speeds up srb tc at the command line and the “Indexing…” operation in editors.

To enable --cache-dir, simply pass --cache-dir=... when invoking srb tc (or add this option to the project’s config file). Replace ... with a path to where Sorbet should write cached data to disk. This ... can either be:

a path to a directory that doesn’t exist (will be created by Sorbet)
a path to an empty directory
a path to a cache directory populated by a previous run of Sorbet

For example:

# Creates or reuses a cache dir at `.sorbet-cache/` in the current dir
srb tc --cache-dir=.sorbet-cache

# Creates or reuses a cache dir at `/tmp/sorbet-cache/`, within the system's
# `/tmp` folder.
srb tc --cache-dir=/tmp/sorbet-cache

Under the hood, Sorbet creates two files in this folder (data.mdb and lock.mdb).

We strongly recommend setting --cache-dir, especially in medium- to large-sized codebases. The parsing and AST rewriting phases of Sorbet are some of the least optimized parts of Sorbet, because historically this caching strategy has been so effective.

What is cached? What is evicted?

The cache is a simple key/value store. The majority of the cache maps keys that look like path/to/file.rb##<CHECKSUM> to a compact binary representation of Sorbet’s internal abstract syntax tree data structure. This means that if srb tc runs twice on a project, but the contents of path/to/file.rb change between the first and second run, there will be two keys in the cache which begin with path/to/file.rb, one for each version of the file. This also means that when checking out an old branch which has already had Sorbet run on it, all tracked and unmodified files will still be in the cache.

This compact binary representation has no stability guarantees, meaning it is not forward nor backward compatible with new versions of Sorbet. Instead, Sorbet completely flushes the cache whenever the Sorbet version string (srb tc --version) changes.

(This version string is only populated correctly for release builds of Sorbet—when using a custom source build of Sorbet which doesn’t build Sorbet in release mode, avoid using --cache-dir.)

Apart from evictions when the Sorbet version changes (e.g. upgrading Sorbet in the Gemfile, or checking out an old commit with an older Sorbet version), Sorbet never evicts data from this cache. It can grow without bound. If disk space is limited, consider Collecting metrics from Sorbet, paying attention to these metrics:

cache.used_bytes
cache.used_percent

(Note that these metrics are only reported when the cache is modified, not when it’s read.)

To simplify Sorbet’s implementation against the underlying key/value store library, the max cache size is fixed when Sorbet starts up. The default max cache size is 4 GiB. The size on disk will only take up as much data as needs to be cached (i., not a fixed 4 GiB). For projects which need more than this, you can use the --max-cache-size-bytes to set a larger cache size. If you find yourself needing to pass this option, please reach out to the Sorbet development team, as your codebase is likely huge (possibly the largest known Sorbet codebase) and we’d like to talk to you.

Is there a way to get errors in JSON format?

There is not, intentionally. If you’re trying to consume Sorbet’s output from a script, we recommend you either consume Sorbet via the LSP protocol, or using standard UNIX tools like sed and awk to extract information from the human-readable output.

Why? Committing to a stable output format is an ongoing maintenance burden for the Sorbet team. We have explicitly chosen only two output formats:

The human-readable error output seen when running srb tc from the CLI directly.
Output conforming to the Language Server Protocol, which drives editor integrations (see the --lsp flag).

The LSP spec is stable, versioned, typed, and easy to test whether Sorbet conforms to it. We don’t want to be in the business of inventing competing editor output formats, so we explicitly only support these two.

This is incidentally why Sorbet does not type check gems: the paths to gems’ source directories are never given to Sorbet. ↩