terraform/internal/tfdiags/consolidate_warnings.go

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package tfdiags
import "fmt"
// ConsolidateWarnings checks if there is an unreasonable amount of warnings
// with the same summary in the receiver and, if so, returns a new diagnostics
// with some of those warnings consolidated into a single warning in order
// to reduce the verbosity of the output.
//
// This mechanism is here primarily for diagnostics printed out at the CLI. In
// other contexts it is likely better to just return the warnings directly,
// particularly if they are going to be interpreted by software rather than
// by a human reader.
//
// The returned slice always has a separate backing array from the reciever,
// but some diagnostic values themselves might be shared.
//
// The definition of "unreasonable" is given as the threshold argument. At most
// that many warnings with the same summary will be shown.
func (diags Diagnostics) ConsolidateWarnings(threshold int) Diagnostics {
if len(diags) == 0 {
return nil
}
newDiags := make(Diagnostics, 0, len(diags))
// We'll track how many times we've seen each warning summary so we can
// decide when to start consolidating. Once we _have_ started consolidating,
// we'll also track the object representing the consolidated warning
// so we can continue appending to it.
warningStats := make(map[string]int)
warningGroups := make(map[string]*warningGroup)
for _, diag := range diags {
severity := diag.Severity()
if severity != Warning || diag.Source().Subject == nil {
// Only warnings can get special treatment, and we only
// consolidate warnings that have source locations because
// our primary goal here is to deal with the situation where
// some configuration language feature is producing a warning
// each time it's used across a potentially-large config.
newDiags = newDiags.Append(diag)
continue
}
desc := diag.Description()
summary := desc.Summary
if g, ok := warningGroups[summary]; ok {
// We're already grouping this one, so we'll just continue it.
g.Append(diag)
continue
}
warningStats[summary]++
if warningStats[summary] == threshold {
// Initially creating the group doesn't really change anything
// visibly in the result, since a group with only one warning
// is just a passthrough anyway, but once we do this any additional
// warnings with the same summary will get appended to this group.
g := &warningGroup{}
newDiags = newDiags.Append(g)
warningGroups[summary] = g
g.Append(diag)
continue
}
// If this warning is not consolidating yet then we'll just append
// it directly.
newDiags = newDiags.Append(diag)
}
return newDiags
}
// A warningGroup is one or more warning diagnostics grouped together for
// UI consolidation purposes.
//
// A warningGroup with only one diagnostic in it is just a passthrough for
// that one diagnostic. If it has more than one then it will behave mostly
// like the first one but its detail message will include an additional
// sentence mentioning the consolidation. A warningGroup with no diagnostics
// at all is invalid and will panic when used.
type warningGroup struct {
Warnings Diagnostics
}
var _ Diagnostic = (*warningGroup)(nil)
func (wg *warningGroup) Severity() Severity {
return wg.Warnings[0].Severity()
}
func (wg *warningGroup) Description() Description {
desc := wg.Warnings[0].Description()
if len(wg.Warnings) < 2 {
return desc
}
extraCount := len(wg.Warnings) - 1
var msg string
switch extraCount {
case 1:
msg = "(and one more similar warning elsewhere)"
default:
msg = fmt.Sprintf("(and %d more similar warnings elsewhere)", extraCount)
}
if desc.Detail != "" {
desc.Detail = desc.Detail + "\n\n" + msg
} else {
desc.Detail = msg
}
return desc
}
func (wg *warningGroup) Source() Source {
return wg.Warnings[0].Source()
}
func (wg *warningGroup) FromExpr() *FromExpr {
return wg.Warnings[0].FromExpr()
}
func (wg *warningGroup) Append(diag Diagnostic) {
if diag.Severity() != Warning {
panic("can't append a non-warning diagnostic to a warningGroup")
}
wg.Warnings = append(wg.Warnings, diag)
}
// WarningGroupSourceRanges can be used in conjunction with
// Diagnostics.ConsolidateWarnings to recover the full set of original source
// locations from a consolidated warning.
//
// For convenience, this function accepts any diagnostic and will just return
// the single Source value from any diagnostic that isn't a warning group.
func WarningGroupSourceRanges(diag Diagnostic) []Source {
wg, ok := diag.(*warningGroup)
if !ok {
return []Source{diag.Source()}
}
ret := make([]Source, len(wg.Warnings))
for i, wrappedDiag := range wg.Warnings {
ret[i] = wrappedDiag.Source()
}
return ret
}