time: fix panic with time.Parse(time.StampNano, ... )

Fixes #4502.

R=rsc
CC=golang-dev
https://golang.org/cl/6949058

diff --git a/src/pkg/time/format.go b/src/pkg/time/format.go
index aab4a4d6b6093db5a8ae2af829f5b4cd4acdce6f..417e8f8d7a80a7f5ead3158fe9c8f2035d1d98bb 100644 (file)
--- a/src/pkg/time/format.go
+++ b/src/pkg/time/format.go
@@ -854,9 +854,15 @@ func Parse(layout, value string) (Time, error) {
                        zoneName = p
 
                case stdFracSecond0:
-                       ndigit := std >> stdArgShift
-                       nsec, rangeErrString, err = parseNanoseconds(value, 1+ndigit)
-                       value = value[1+ndigit:]
+                       // stdFracSecond0 requires the exact number of digits as specified in
+                       // the layout.
+                       ndigit := 1 + (std >> stdArgShift)
+                       if len(value) < ndigit {
+                               err = errBad
+                               break
+                       }
+                       nsec, rangeErrString, err = parseNanoseconds(value, ndigit)
+                       value = value[ndigit:]
 
                case stdFracSecond9:
                        if len(value) < 2 || value[0] != '.' || value[1] < '0' || '9' < value[1] {
@@ -934,8 +940,7 @@ func parseNanoseconds(value string, nbytes int) (ns int, rangeErrString string,
                err = errBad
                return
        }
-       ns, err = atoi(value[1:nbytes])
-       if err != nil {
+       if ns, err = atoi(value[1:nbytes]); err != nil {
                return
        }
        if ns < 0 || 1e9 <= ns {

diff --git a/src/pkg/time/time_test.go b/src/pkg/time/time_test.go
index 1fd575b0956e6f857e0de0b420d082784e6cedd7..0224fed4bdfcb88355051fc9e10551ba8536701b 100644 (file)
--- a/src/pkg/time/time_test.go
+++ b/src/pkg/time/time_test.go
@@ -469,7 +469,7 @@ type ParseTest struct {
        value      string
        hasTZ      bool // contains a time zone
        hasWD      bool // contains a weekday
-       yearSign   int  // sign of year
+       yearSign   int  // sign of year, -1 indicates the year is not present in the format
        fracDigits int  // number of digits of fractional second
 }
 
@@ -514,6 +514,13 @@ var parseTests = []ParseTest{
        {"", "2006-01-02 15:04:05.999999999 -0700 MST", "2010-02-04 21:00:57.0123 -0800 PST", true, false, 1, 4},
        {"", "2006-01-02 15:04:05.9999 -0700 MST", "2010-02-04 21:00:57.012345678 -0800 PST", true, false, 1, 9},
        {"", "2006-01-02 15:04:05.999999999 -0700 MST", "2010-02-04 21:00:57.012345678 -0800 PST", true, false, 1, 9},
+
+       // issue 4502.
+       {"", StampNano, "Feb  4 21:00:57.012345678", false, false, -1, 9},
+       {"", "Jan _2 15:04:05.999", "Feb  4 21:00:57.012300000", false, false, -1, 4},
+       {"", "Jan _2 15:04:05.999", "Feb  4 21:00:57.012345678", false, false, -1, 9},
+       {"", "Jan _2 15:04:05.999999999", "Feb  4 21:00:57.0123", false, false, -1, 4},
+       {"", "Jan _2 15:04:05.999999999", "Feb  4 21:00:57.012345678", false, false, -1, 9},
 }
 
 func TestParse(t *testing.T) {
@@ -549,7 +556,7 @@ func TestRubyParse(t *testing.T) {
 
 func checkTime(time Time, test *ParseTest, t *testing.T) {
        // The time should be Thu Feb  4 21:00:57 PST 2010
-       if test.yearSign*time.Year() != 2010 {
+       if test.yearSign >= 0 && test.yearSign*time.Year() != 2010 {
                t.Errorf("%s: bad year: %d not %d", test.name, time.Year(), 2010)
        }
        if time.Month() != February {
@@ -630,6 +637,9 @@ var parseErrorTests = []ParseErrorTest{
        {"Mon Jan _2 15:04:05.000 2006", "Thu Feb  4 23:00:59x01 2010", "cannot parse"},
        {"Mon Jan _2 15:04:05.000 2006", "Thu Feb  4 23:00:59.xxx 2010", "cannot parse"},
        {"Mon Jan _2 15:04:05.000 2006", "Thu Feb  4 23:00:59.-123 2010", "fractional second out of range"},
+       // issue 4502. StampNano requires exactly 9 digits of precision.
+       {StampNano, "Dec  7 11:22:01.000000", `cannot parse ".000000" as ".000000000"`},
+       {StampNano, "Dec  7 11:22:01.0000000000", "extra text: 0"},
 }
 
 func TestParseErrors(t *testing.T) {