mirror of
https://github.com/go-sylixos/elvish.git
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1e0885310e
When attempting to update a read-only var return an error struct rather
than a simple string (i.e., a Go `error` type). This makes it possible
to include the var name in the error message. This builds on commit
a33ecb2d that highlights the offending var name in the stack trace but
does not include the var name in the error message. With this change the
error message includes the offending var name.
Related #255
78 lines
1.9 KiB
Go
78 lines
1.9 KiB
Go
// Package errs declares Elvish error types that are not simple strings (i.e., the Go `error` type).
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package errs
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import (
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"fmt"
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"strconv"
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)
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// OutOfRange encodes an error where a value is out of its valid range.
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type OutOfRange struct {
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What string
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ValidLow string
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ValidHigh string
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Actual string
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}
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func (e OutOfRange) Error() string {
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if e.ValidHigh < e.ValidLow {
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return fmt.Sprintf(
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"out of range: %v has no valid value, but is %v", e.What, e.Actual)
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}
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return fmt.Sprintf(
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"out of range: %s must be from %s to %s, but is %s",
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e.What, e.ValidLow, e.ValidHigh, e.Actual)
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}
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// BadValue encodes an error where the value does not meet a requirement. For
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// out-of-range erros, use OutOfRange.
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type BadValue struct {
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What string
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Valid string
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Actual string
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}
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func (e BadValue) Error() string {
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return fmt.Sprintf(
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"bad value: %v must be %v, but is %v", e.What, e.Valid, e.Actual)
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}
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// ArityMismatch encodes an error where the expected number of values is out of
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// the valid range.
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type ArityMismatch struct {
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What string
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ValidLow int
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ValidHigh int
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Actual int
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}
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func (e ArityMismatch) Error() string {
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switch {
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case e.ValidHigh == e.ValidLow:
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return fmt.Sprintf("arity mismatch: %v must be %v, but is %v",
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e.What, nValues(e.ValidLow), nValues(e.Actual))
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case e.ValidHigh == -1:
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return fmt.Sprintf("arity mismatch: %v must be %v or more values, but is %v",
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e.What, e.ValidLow, nValues(e.Actual))
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default:
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return fmt.Sprintf("arity mismatch: %v must be %v to %v values, but is %v",
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e.What, e.ValidLow, e.ValidHigh, nValues(e.Actual))
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}
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}
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func nValues(n int) string {
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if n == 1 {
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return "1 value"
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}
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return strconv.Itoa(n) + " values"
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}
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// SetReadOnlyVar is returned by the Set method of a read-only variable.
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type SetReadOnlyVar struct {
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VarName string
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}
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func (e SetReadOnlyVar) Error() string {
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return fmt.Sprintf("cannot set read-only variable %q", e.VarName)
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}
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