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Fix negative duration parsing #552

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Fix negative duration parsing #552

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12 changes: 10 additions & 2 deletions pkg/validation/strfmt/duration.go
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Original file line number Diff line number Diff line change
Expand Up @@ -52,7 +52,7 @@ var (
"w": 7 * 24 * time.Hour,
}

durationMatcher = regexp.MustCompile(`((\d+)\s*([A-Za-zµ]+))`)
durationMatcher = regexp.MustCompile(`(((?:-\s?)?\d+)\s*([A-Za-zµ]+))`)
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can you clarify what additional values this allows? it's not clear to me that accepting new internal whitespaces between - and the number is a good idea here

)

// IsDuration returns true if the provided string is a valid duration
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@liggitt liggitt Aug 14, 2025 •
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ParseDuration uses durationMatcher.FindAllStringSubmatch with an unpinned regex, which will skip and ignore any random junk before / between / after matches of the regex.

See https://go.dev/play/p/fCur5WS4zK5 for the type of nonsense IsDuration would accept currently.

To actually address the problem of decimal junk being accepted but ignored, we need the regex to fully define what we allow, and be pinned to the beginning / end of the string. Something like this

singleDurationMatcher = `-?(\d+)\s*([A-Za-zµ]+)`
// I'm not sure what separators we *intend* to allow between the items, whitespace? comma? something else?
multiDuration = `^(`+singleDurationMatcher+`)(\s*`+singleDurationMatcher+`)*$`
durationMatcher = regexp.MustCompile(multiDuration)
...

Expand Down Expand Up @@ -94,10 +94,18 @@ func ParseDuration(cand string) (time.Duration, error) {
ok := false
for _, match := range durationMatcher.FindAllStringSubmatch(cand, -1) {

factor, err := strconv.Atoi(match[2]) // converts string to int
// remove possible leading - and spaces
value, negative := strings.CutPrefix(match[2], "-")

// if the string is a valid duration, parse it
factor, err := strconv.Atoi(strings.TrimSpace(value)) // converts string to int
if err != nil {
return 0, err
}

if negative {
factor = -factor
}
unit := strings.ToLower(strings.TrimSpace(match[3]))

for _, variants := range timeUnits {
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8 changes: 7 additions & 1 deletion pkg/validation/strfmt/duration_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -141,7 +141,13 @@ func TestDurationParser(t *testing.T) {
}

for str, dur := range testcases {
testDurationParser(t, str, dur)
t.Run(str, func(t *testing.T) {
testDurationParser(t, str, dur)

// negative duration
testDurationParser(t, "-"+str, -dur)
testDurationParser(t, "- "+str, -dur)
})
}
}
func TestIsDuration_Caveats(t *testing.T) {
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