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ceph-csi/vendor/github.com/ansel1/merry/doc.go

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// Package merry provides enriched golang errors, with stacktraces
//
// merry creates errors with stacktraces, and can augment those errors with additional
// information.
//
// When you create a new merry error, or wrap an existing error in a merry error, merry attaches
// a stacktrace to the error:
//
// err := merry.New("an error occurred")
//
// err has a stacktrace attached. Alternately, you can wrap existing errors. merry will
// attach a stacktrace at the point of wrapping:
//
// _, err := ioutil.ReadAll(r)
// if err != nil {
// return merry.Wrap(err)
// }
//
// Capturing the stack can be globally disabled with `SetStackCaptureEnabled(false)`. Wrapping
// is idempotent: Wrap will only attach a stacktrace if the error doesn't already have one.
//
// Wrap() is the simplest way to attach a stacktrace to an error, but other functions can be
// used instead, with both add a stacktrace, and augment or modify the error. For example,
// Prepend() modifies the error's message (and also attaches a stacktrace):
//
// _, err := ioutil.ReadAll(r)
// if err != nil {
// return merry.Prepend(err, "reading from conn failed")
// // err.Error() would read something like "reading from conn failed: timeout"
// }
//
// See the other package functions for other ways to augment or modify errors, such as Append,
// WithUserMessage, WithHTTPCode, WithValue, etc. These functions all return a merry.Error interface, which
// has methods which mirror the package level functions, to allow simple chaining:
//
// return merry.New("object not found").WithHTTPCode(404)
//
// Here
//
// Wrap will not take a new stacktrace if an error already has one attached. Here will create
// a new error which replaces the stacktrace with a new one:
//
// var ErrOverflow = merry.New("overflowed")
//
// func Read() error {
// // ...
// return merry.Here(ErrOverflow)
// }
//
// Is
//
// The go idiom of exporting package-level error variables for comparison to errors returned
// by the package is broken by merry. For example:
//
// _, err := io.ReadAll(r)
// if err == io.EOF {
// // ...
// }
//
// If the error returned was a merry error, the equality comparison would always fail, because merry
// augments errors by wrapping them in layers. To compensate for this, merry has the Is() function.
//
// if merry.Is(err, io.EOF) {
//
// Is() will unwrap the err and compare each layer to the second argument.
//
// Cause
//
// You can add a cause to an error:
//
// if err == io.EOF {
// err = merry.New("reading failed"), err)
// fmt.Println(err.Error()) // reading failed: EOF
// }
//
// Cause(error) will return the cause of the argument. RootCause(error) returns the innermost cause.
// Is(err1, err2) is cause aware, and will return true if err2 is a cause (anywhere in the causal change)
// of err1.
//
// Formatting and printing
//
// To obtain an error's stacktrace, call Stack(). To get other information about the site
// of the error, or print the error's stacktrace, see Location(), SourceLine(), Stacktrace(), and Details().
//
// merry errors also implement the fmt.Formatter interface. errors support the following fmt flags:
//
// %+v print the equivalent of Details(err), which includes the user message, full stacktrace,
// and recursively prints the details of the cause chain.
//
package merry