text/template: document redefinition of templates

[icza]

Go home page, Go 1.7.1.

Package text/template and html/template provide the same interface. But the documentation of text/template.Parse() and html/template.Parse() are different.

text/template.Parse() leaves out an important fact that it is an error to redefine a non-empty template. html/template.Parse() contains this important fact. But they work the same way.

I believe when {{block}} action was added in Go 1.6 and redefining of templates got allowed, only the doc of html/template.Parse() was updated but not text/template.Parse().

Example code that triggers this error:

template.Must(template.New("").Parse(`{{block "A" "a"}}a{{end}}{{define "A"}}b{{end}}`))

Playground link with text/template: https://play.golang.org/p/PY3zLcCFiu

Playground link with html/template: https://play.golang.org/p/UeQk4D3tcB

[gopherbot]

CL https://golang.org/cl/31459 mentions this issue.