tpl: Workaround s390x precision of Atan and Tan

On s390x, math.Atan(1) and math.Tan(1) give values that slightly differ
from other architectures, causing TestTemplateFuncsExamples to fail.

The golang math package states in the overview:
"This package does not guarantee bit-identical results across architectures."

diff --git a/tpl/math/init.go b/tpl/math/init.go
index bb3c02bd6cef5098e656c58fedfa67fa2a1ceed6..e34c892f076529deda210a75e93fd943135b5ac5 100644 (file)
--- a/tpl/math/init.go
+++ b/tpl/math/init.go
@@ -15,6 +15,7 @@ package math
 
 import (
        "context"
+       "runtime"
 
        "github.com/gohugoio/hugo/deps"
        "github.com/gohugoio/hugo/tpl/internal"
@@ -23,6 +24,13 @@ import (
 const name = "math"
 
 func init() {
+       mathAtan1 := "0.7853981633974483"
+       mathTan1 := "1.557407724654902"
+       if runtime.GOARCH == "s390x" {
+               mathAtan1 = "0.7853981633974484"
+               mathTan1 = "1.5574077246549018"
+       }
+
        f := func(d *deps.Deps) *internal.TemplateFuncsNamespace {
                ctx := New(d)
 
@@ -62,7 +70,7 @@ func init() {
                ns.AddMethodMapping(ctx.Atan,
                        nil,
                        [][2]string{
-                               {"{{ math.Atan 1 }}", "0.7853981633974483"},
+                               {"{{ math.Atan 1 }}", mathAtan1},
                        },
                )
 
@@ -202,7 +210,7 @@ func init() {
                ns.AddMethodMapping(ctx.Tan,
                        nil,
                        [][2]string{
-                               {"{{ math.Tan 1 }}", "1.557407724654902"},
+                               {"{{ math.Tan 1 }}", mathTan1},
                        },
                )