internal/export/idna: don't remove leading dots
Dots are still removed for profiles for which this makes sense.
Update golang/go#19821
Change-Id: I3de20bc5ddd943557831d1de998554105d7c07e7
Reviewed-on: https://go-review.googlesource.com/44380
Run-TryBot: Marcel van Lohuizen <mpvl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Nigel Tao <nigeltao@golang.org>
diff --git a/internal/export/idna/idna.go b/internal/export/idna/idna.go
index 3184fbb..4711196 100644
--- a/internal/export/idna/idna.go
+++ b/internal/export/idna/idna.go
@@ -67,6 +67,15 @@
return func(o *options) { o.verifyDNSLength = verify }
}
+// RemoveLeadingDots removes leading label separators. Leading runes that map to
+// dots, such as U+3002 IDEOGRAPHIC FULL STOP, are removed as well.
+//
+// This is the behavior suggested by the UTS #46 and is adopted by some
+// browsers.
+func RemoveLeadingDots(remove bool) Option {
+ return func(o *options) { o.removeLeadingDots = remove }
+}
+
// ValidateLabels sets whether to check the mandatory label validation criteria
// as defined in Section 5.4 of RFC 5891. This includes testing for correct use
// of hyphens ('-'), normalization, validity of runes, and the context rules.
@@ -133,14 +142,16 @@
o.mapping = validateAndMap
StrictDomainName(true)(o)
ValidateLabels(true)(o)
+ RemoveLeadingDots(true)(o)
}
}
type options struct {
- transitional bool
- useSTD3Rules bool
- validateLabels bool
- verifyDNSLength bool
+ transitional bool
+ useSTD3Rules bool
+ validateLabels bool
+ verifyDNSLength bool
+ removeLeadingDots bool
trie *idnaTrie
@@ -240,21 +251,23 @@
punycode = &Profile{}
lookup = &Profile{options{
- transitional: true,
- useSTD3Rules: true,
- validateLabels: true,
- trie: trie,
- fromPuny: validateFromPunycode,
- mapping: validateAndMap,
- bidirule: bidirule.ValidString,
+ transitional: true,
+ useSTD3Rules: true,
+ validateLabels: true,
+ removeLeadingDots: true,
+ trie: trie,
+ fromPuny: validateFromPunycode,
+ mapping: validateAndMap,
+ bidirule: bidirule.ValidString,
}}
display = &Profile{options{
- useSTD3Rules: true,
- validateLabels: true,
- trie: trie,
- fromPuny: validateFromPunycode,
- mapping: validateAndMap,
- bidirule: bidirule.ValidString,
+ useSTD3Rules: true,
+ validateLabels: true,
+ removeLeadingDots: true,
+ trie: trie,
+ fromPuny: validateFromPunycode,
+ mapping: validateAndMap,
+ bidirule: bidirule.ValidString,
}}
registration = &Profile{options{
useSTD3Rules: true,
@@ -293,7 +306,9 @@
s, err = p.mapping(p, s)
}
// Remove leading empty labels.
- for ; len(s) > 0 && s[0] == '.'; s = s[1:] {
+ if p.removeLeadingDots {
+ for ; len(s) > 0 && s[0] == '.'; s = s[1:] {
+ }
}
// It seems like we should only create this error on ToASCII, but the
// UTS 46 conformance tests suggests we should always check this.
diff --git a/internal/export/idna/idna_test.go b/internal/export/idna/idna_test.go
index 01fd50b..82ead03 100644
--- a/internal/export/idna/idna_test.go
+++ b/internal/export/idna/idna_test.go
@@ -117,7 +117,7 @@
f func(string) (string, error)
}
punyA := kind{"PunycodeA", punycode.ToASCII}
- resolve := kind{"ToASCII", Lookup.ToASCII}
+ resolve := kind{"ResolveA", Lookup.ToASCII}
display := kind{"ToUnicode", Display.ToUnicode}
p := New(VerifyDNSLength(true), MapForLookup(), BidiRule())
lengthU := kind{"CheckLengthU", p.ToUnicode}
@@ -145,16 +145,25 @@
{display, "foo.xn--.bar", "foo..bar", ""},
{lengthA, "a..b", "a..b", "A4"},
- // Stripping leading empty labels here but not for "empty" punycode
- // above seems inconsistent, but seems to be applied by both the
- // conformance test and Chrome. Different interpretations would be
- // possible, though.
+ {punyA, ".b", ".b", ""},
+ // For backwards compatibility, the Punycode profile does not map runes.
+ {punyA, "\u3002b", "xn--b-83t", ""},
+ {punyA, "..b", "..b", ""},
+ // Only strip leading empty labels for certain profiles. Stripping
+ // leading empty labels here but not for "empty" punycode above seems
+ // inconsistent, but seems to be applied by both the conformance test
+ // and Chrome. So we turn it off by default, support it as an option,
+ // and enable it in profiles where it seems commonplace.
+ {lengthA, ".b", "b", ""},
+ {lengthA, "\u3002b", "b", ""},
{lengthA, "..b", "b", ""},
- {lengthA, "b..", "b..", ""}, // TODO: remove trailing dots?
+ {lengthA, "b..", "b..", ""},
{resolve, "a..b", "a..b", ""},
+ {resolve, ".b", "b", ""},
+ {resolve, "\u3002b", "b", ""},
{resolve, "..b", "b", ""},
- {resolve, "b..", "b..", ""}, // TODO: remove trailing dots?
+ {resolve, "b..", "b..", ""},
// Raw punycode
{punyA, "", "", ""},
