@spec blame(:error, any(), stacktrace()) :: {t(), stacktrace()}

@spec blame(non_error_kind(), payload, stacktrace()) :: {payload, stacktrace()}
when payload: var

Attaches information to exceptions for extra debugging.

This operation is potentially expensive, as it reads data from the file system, parses beam files, evaluates code and so on.

If the exception module implements the optional blame/2 callback, it will be invoked to perform the computation.

@spec blame_mfa(module(), function :: atom(), args :: [term()]) ::
  {:ok, :def | :defp | :defmacro | :defmacrop,
   [{args :: [term()], guards :: [term()]}]}
  | :error

Blames the invocation of the given module, function and arguments.

This function will retrieve the available clauses from bytecode and evaluate them against the given arguments. The clauses are returned as a list of {args, guards} pairs where each argument and each top-level condition in a guard separated by and/or is wrapped in a tuple with blame metadata.

This function returns either {:ok, definition, clauses} or :error. Where definition is :def, :defp, :defmacro or :defmacrop.

@spec format(kind(), any(), stacktrace()) :: String.t()

Normalizes and formats throw/errors/exits and stacktraces.

It relies on format_banner/3 and format_stacktrace/1 to generate the final format.

If kind is {:EXIT, pid}, it does not generate a stacktrace, as such exits are retrieved as messages without stacktraces.

@spec format_banner(kind(), any(), stacktrace()) :: String.t()

Normalizes and formats any throw/error/exit.

The message is formatted and displayed in the same format as used by Elixir's CLI.

The third argument is the stacktrace which is used to enrich a normalized error with more information. It is only used when the kind is an error.

@spec format_exit(any()) :: String.t()

Formats an exit. It returns a string.

Often there are errors/exceptions inside exits. Exits are often wrapped by the caller and provide stacktraces too. This function formats exits in a way to nicely show the exit reason, caller and stacktrace.

@spec format_fa((... -> any()), arity()) :: String.t()

Receives an anonymous function and arity and formats it as shown in stacktraces. The arity may also be a list of arguments.

Examples

Exception.format_fa(fn -> nil end, 1)
#=> "#Function<...>/1"

@spec format_file_line(String.t() | nil, non_neg_integer() | nil, String.t()) ::
  String.t()

Formats the given file and line as shown in stacktraces.

If any of the values are nil, they are omitted.

Examples

iex> Exception.format_file_line("foo", 1)
"foo:1:"

iex> Exception.format_file_line("foo", nil)
"foo:"

iex> Exception.format_file_line(nil, nil)
""

@spec format_file_line_column(
  String.t() | nil,
  non_neg_integer() | nil,
  non_neg_integer() | nil,
  String.t()
) :: String.t()

Formats the given file, line, and column as shown in stacktraces.

If any of the values are nil, they are omitted.

Examples

iex> Exception.format_file_line_column("foo", 1, 2)
"foo:1:2:"

iex> Exception.format_file_line_column("foo", 1, nil)
"foo:1:"

iex> Exception.format_file_line_column("foo", nil, nil)
"foo:"

iex> Exception.format_file_line_column("foo", nil, 2)
"foo:"

iex> Exception.format_file_line_column(nil, nil, nil)
""

@spec format_mfa(module(), atom(), arity_or_args()) :: String.t()

Receives a module, fun and arity and formats it as shown in stacktraces. The arity may also be a list of arguments.

Examples

iex> Exception.format_mfa(Foo, :bar, 1)
"Foo.bar/1"

iex> Exception.format_mfa(Foo, :bar, [])
"Foo.bar()"

iex> Exception.format_mfa(nil, :bar, [])
"nil.bar()"

Anonymous functions are reported as -func/arity-anonfn-count-, where func is the name of the enclosing function. Convert to "anonymous fn in func/arity"

@spec format_stacktrace(stacktrace() | nil) :: String.t()

Formats the stacktrace.

A stacktrace must be given as an argument. If not, the stacktrace is retrieved from Process.info/2.

@spec format_stacktrace_entry(stacktrace_entry()) :: String.t()

Receives a stacktrace entry and formats it into a string.

@spec message(t()) :: String.t()

Gets the message for an exception.

@spec normalize(:error, any(), stacktrace()) :: t()

@spec normalize(non_error_kind(), payload, stacktrace()) :: payload when payload: var

Normalizes an exception, converting Erlang exceptions to Elixir exceptions.

It takes the kind spilled by catch as an argument and normalizes only :error, returning the untouched payload for others.

The third argument is the stacktrace which is used to enrich a normalized error with more information. It is only used when the kind is an error.