strconv: revert ParseFloat/ParseComplex error on incorrect bitSize
This is a partial revert of https://go-review.googlesource.com/c/go/+/248219
because we found that a non-trivial amount of code erroneously calls
ParseFloat(s, 10) or even ParseFloat(s, 0) and expects it to work --
before that change was merged, ParseFloat accepted a bitSize of
anything other than 32 or 64 to mean 64 (and ParseComplex was similar).
So revert that behavior to avoid breaking people's code, and add tests
for this.
I may add a vet check to flag ParseFloat(s, not_32_or_64) in a later
change.
See #42297 for more details.
Change-Id: I4bc0156bd74f67a39d5561b6e5fde3f2d20bd622
Reviewed-on: https://go-review.googlesource.com/c/go/+/267319
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Robert Griesemer <gri@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
diff --git a/src/strconv/atoc.go b/src/strconv/atoc.go
index 52cb590..85c7baf 100644
--- a/src/strconv/atoc.go
+++ b/src/strconv/atoc.go
@@ -40,10 +40,10 @@
// away from the largest floating point number of the given component's size,
// ParseComplex returns err.Err = ErrRange and c = ±Inf for the respective component.
func ParseComplex(s string, bitSize int) (complex128, error) {
- if bitSize != 64 && bitSize != 128 {
- return 0, bitSizeError(fnParseComplex, s, bitSize)
+ size := 64
+ if bitSize == 64 {
+ size = 32 // complex64 uses float32 parts
}
- size := bitSize >> 1
orig := s
diff --git a/src/strconv/atoc_test.go b/src/strconv/atoc_test.go
index aecc09d..4c1aad0 100644
--- a/src/strconv/atoc_test.go
+++ b/src/strconv/atoc_test.go
@@ -212,13 +212,18 @@
}
}
-func TestParseComplexInvalidBitSize(t *testing.T) {
- _, err := ParseComplex("1+2i", 100)
- const want = `strconv.ParseComplex: parsing "1+2i": invalid bit size 100`
- if err == nil {
- t.Fatalf("got nil error, want %q", want)
- }
- if err.Error() != want {
- t.Fatalf("got error %q, want %q", err, want)
+// Issue 42297: allow ParseComplex(s, not_32_or_64) for legacy reasons
+func TestParseComplexIncorrectBitSize(t *testing.T) {
+ const s = "1.5e308+1.0e307i"
+ const want = 1.5e308 + 1.0e307i
+
+ for _, bitSize := range []int{0, 10, 100, 256} {
+ c, err := ParseComplex(s, bitSize)
+ if err != nil {
+ t.Fatalf("ParseComplex(%q, %d) gave error %s", s, bitSize, err)
+ }
+ if c != want {
+ t.Fatalf("ParseComplex(%q, %d) = %g (expected %g)", s, bitSize, c, want)
+ }
}
}
diff --git a/src/strconv/atof.go b/src/strconv/atof.go
index a04f562..9010a66 100644
--- a/src/strconv/atof.go
+++ b/src/strconv/atof.go
@@ -688,9 +688,6 @@
// ParseFloat recognizes the strings "NaN", and the (possibly signed) strings "Inf" and "Infinity"
// as their respective special floating point values. It ignores case when matching.
func ParseFloat(s string, bitSize int) (float64, error) {
- if bitSize != 32 && bitSize != 64 {
- return 0, bitSizeError(fnParseFloat, s, bitSize)
- }
f, n, err := parseFloatPrefix(s, bitSize)
if err == nil && n != len(s) {
return 0, syntaxError(fnParseFloat, s)
diff --git a/src/strconv/atof_test.go b/src/strconv/atof_test.go
index cf43903..3c058b9 100644
--- a/src/strconv/atof_test.go
+++ b/src/strconv/atof_test.go
@@ -634,14 +634,20 @@
t.Logf("tested %d float32's", count)
}
-func TestParseFloatInvalidBitSize(t *testing.T) {
- _, err := ParseFloat("3.14", 100)
- const want = `strconv.ParseFloat: parsing "3.14": invalid bit size 100`
- if err == nil {
- t.Fatalf("got nil error, want %q", want)
- }
- if err.Error() != want {
- t.Fatalf("got error %q, want %q", err, want)
+// Issue 42297: a lot of code in the wild accidentally calls ParseFloat(s, 10)
+// or ParseFloat(s, 0), so allow bitSize values other than 32 and 64.
+func TestParseFloatIncorrectBitSize(t *testing.T) {
+ const s = "1.5e308"
+ const want = 1.5e308
+
+ for _, bitSize := range []int{0, 10, 100, 128} {
+ f, err := ParseFloat(s, bitSize)
+ if err != nil {
+ t.Fatalf("ParseFloat(%q, %d) gave error %s", s, bitSize, err)
+ }
+ if f != want {
+ t.Fatalf("ParseFloat(%q, %d) = %g (expected %g)", s, bitSize, f, want)
+ }
}
}
