lib/json: encode floating point numbers with a decimal point
The previous code carelessly used Go's %g operator
when it should have used Starlark's.
Fixes #563
diff --git a/lib/json/json.go b/lib/json/json.go
index 5979b6f..bc67be5 100644
--- a/lib/json/json.go
+++ b/lib/json/json.go
@@ -147,7 +147,8 @@
if !isFinite(float64(x)) {
return fmt.Errorf("cannot encode non-finite float %v", x)
}
- fmt.Fprintf(buf, "%g", x) // always contains a decimal point
+ // Float.String always contains a decimal point. (%g does not!)
+ buf.WriteString(x.String())
case starlark.String:
quote(string(x))
diff --git a/starlark/testdata/json.star b/starlark/testdata/json.star
index 62a457b..1df9dee 100644
--- a/starlark/testdata/json.star
+++ b/starlark/testdata/json.star
@@ -144,8 +144,13 @@
0, 1, -1, +1, 1.23e45, -1.23e-45,
3539537889086624823140625,
float(3539537889086624823140625),
+ float(1.0),
]
-assert.eq(codec(numbers), numbers)
+def number_roundtrip():
+ show = lambda n: (n, type(n))
+ for n in numbers:
+ assert.eq(show(codec(n)), show(n)) # ensure no int/float confusion
+number_roundtrip()
## json.indent
