fmt: document and fix the handling of precision for strings and byte slices
Previous behavior was undocumented and inconsistent. Now it is documented
and consistent and measures the input size, since that makes more sense
when talking about %q and %x. For %s the change has no effect.
Fixes #8151.
LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/144540044
diff --git a/src/fmt/format.go b/src/fmt/format.go
index 255167c..a92f3c2 100644
--- a/src/fmt/format.go
+++ b/src/fmt/format.go
@@ -340,11 +340,17 @@
// fmt_sx formats a string as a hexadecimal encoding of its bytes.
func (f *fmt) fmt_sx(s, digits string) {
+ if f.precPresent && f.prec < len(s) {
+ s = s[:f.prec]
+ }
f.fmt_sbx(s, nil, digits)
}
// fmt_bx formats a byte slice as a hexadecimal encoding of its bytes.
func (f *fmt) fmt_bx(b []byte, digits string) {
+ if f.precPresent && f.prec < len(b) {
+ b = b[:f.prec]
+ }
f.fmt_sbx("", b, digits)
}
