bug: ComponentScript rendered even when 'if condition' fails

[luxxxoor]

Describe the bug
RenderScriptItems is called everytime even though the ComponentScript is incapsulated in an if condition.

To Reproduce
A small, self-container, complete reproduction, uploaded to a Github repo, containing the minimum amount of files required to reproduce the behaviour, along with a list of commands that need to be run. Keep it simple.

templ button(title string, action *templ.ComponentScript) {
	<button>
	        if action != nil {
			onclick={ action }
		}
               { title }
	</button>
}

Expected behaviour
I expect passing a nil action to not break rendering of the button.

Screenshots
N/A

Logs

panic: runtime error: invalid memory address or nil pointer dereference
 
 -> project/view/components/button.Model.Render.component.func1
 ->   /Users/user/Development/project/view/components/button/button_templ.go:34

    project/view/components/button.Model.Render.component.GeneratedTemplate.func2
      /Users/user/go/1.22.0/pkg/mod/github.com/a-h/[email protected]/runtime/runtime.go:19
    github.com/a-h/templ.ComponentFunc.Render
      /Users/user/go/1.22.0/pkg/mod/github.com/a-h/[email protected]/runtime.go:40
    project/components/experiences.HandleNavExperiences.Experiences.func1
      /Users/user/Development/project/view/experiences/experiences_templ.go:223
    project/components/experiences.HandleNavExperiences.Experiences.GeneratedTemplate.func2
      /Users/user/go/1.22.0/pkg/mod/github.com/a-h/[email protected]/runtime/runtime.go:19
    github.com/a-h/templ.ComponentFunc.Render
      /Users/user/go/1.22.0/pkg/mod/github.com/a-h/[email protected]/runtime.go:40
    project/http_ext.(*ComponentHandler).Render.func1
      /Users/user/Development/project/http_ext/component_handler.go:35
    net/http.HandlerFunc.ServeHTTP
      /Users/user/.goenv/versions/1.22.0/src/net/http/server.go:2166
    main.redirectToLogin.func1
      /Users/user/Development/project/middlewares.go:76
    net/http.HandlerFunc.ServeHTTP
      /Users/user/.goenv/versions/1.22.0/src/net/http/server.go:2166
    github.com/go-chi/chi/v5.(*ChainHandler).ServeHTTP
      /Users/user/go/1.22.0/pkg/mod/github.com/go-chi/chi/[email protected]/chain.go:31
    github.com/go-chi/chi/v5.(*Mux).routeHTTP
      /Users/user/go/1.22.0/pkg/mod/github.com/go-chi/chi/[email protected]/mux.go:459
    net/http.HandlerFunc.ServeHTTP
      /Users/user/.goenv/versions/1.22.0/src/net/http/server.go:2166
    main.main.connectionPool.func5.1
      /Users/user/Development/project/middlewares.go:55
    net/http.HandlerFunc.ServeHTTP
      /Users/user/.goenv/versions/1.22.0/src/net/http/server.go:2166
    main.userSettings.func1
      /Users/user/Development/project/middlewares.go:47
    net/http.HandlerFunc.ServeHTTP
      /Users/user/.goenv/versions/1.22.0/src/net/http/server.go:2166
    main.main.Verifier.Verify.func7.1
      /Users/user/go/1.22.0/pkg/mod/github.com/go-chi/jwtauth/[email protected]/jwtauth.go:78
    net/http.HandlerFunc.ServeHTTP
      /Users/user/.goenv/versions/1.22.0/src/net/http/server.go:2166
    main.main.Timeout.func4.1
      /Users/user/go/1.22.0/pkg/mod/github.com/go-chi/chi/[email protected]/middleware/timeout.go:44
    net/http.HandlerFunc.ServeHTTP
      /Users/user/.goenv/versions/1.22.0/src/net/http/server.go:2166
    github.com/go-chi/chi/v5/middleware.RedirectSlashes.func1
      /Users/user/go/1.22.0/pkg/mod/github.com/go-chi/chi/[email protected]/middleware/strip.go:59
    net/http.HandlerFunc.ServeHTTP
      /Users/user/.goenv/versions/1.22.0/src/net/http/server.go:2166
    github.com/go-chi/chi/v5/middleware.Recoverer.func1
      /Users/user/go/1.22.0/pkg/mod/github.com/go-chi/chi/[email protected]/middleware/recoverer.go:45
    net/http.HandlerFunc.ServeHTTP
      /Users/user/.goenv/versions/1.22.0/src/net/http/server.go:2166
    github.com/go-chi/chi/v5/middleware.init.0.RequestLogger.func1.1
      /Users/user/go/1.22.0/pkg/mod/github.com/go-chi/chi/[email protected]/middleware/logger.go:55
    net/http.HandlerFunc.ServeHTTP
      /Users/user/.goenv/versions/1.22.0/src/net/http/server.go:2166
    github.com/go-chi/chi/v5/middleware.RealIP.func1
      /Users/user/go/1.22.0/pkg/mod/github.com/go-chi/chi/[email protected]/middleware/realip.go:36
    net/http.HandlerFunc.ServeHTTP
      /Users/user/.goenv/versions/1.22.0/src/net/http/server.go:2166
    github.com/go-chi/chi/v5/middleware.RequestID.func1
      /Users/user/go/1.22.0/pkg/mod/github.com/go-chi/chi/[email protected]/middleware/request_id.go:76
    net/http.HandlerFunc.ServeHTTP
      /Users/user/.goenv/versions/1.22.0/src/net/http/server.go:2166
    github.com/go-chi/chi/v5.(*Mux).ServeHTTP
      /Users/user/go/1.22.0/pkg/mod/github.com/go-chi/chi/[email protected]/mux.go:90
    net/http.serverHandler.ServeHTTP
      /Users/user/.goenv/versions/1.22.0/src/net/http/server.go:3137
    net/http.(*conn).serve
      /Users/user/.goenv/versions/1.22.0/src/net/http/server.go:2039
    created by net/http.(*Server).Serve in goroutine 1
      /Users/user/.goenv/versions/1.22.0/src/net/http/server.go:3285

templ info output
Run templ info and include the output.

(✓) os [ goos=darwin goarch=arm64 ]
(✓) go [ location=/Users/user/.goenv/versions/1.22.0/bin/go version=go version go1.22.0 darwin/arm64 ]
(✓) gopls [ location=/Users/user/go/1.22.0/bin/gopls version=golang.org/x/tools/gopls v0.16.1 ]
(✓) templ [ location=/Users/user/go/1.22.0/bin/templ version=v0.2.771 ]

Desktop (please complete the following information):

• OS: MacOS
• templ CLI version (templ version): v0.2.771
• Go version (go version): go version go1.22.0 darwin/arm64
• gopls version (gopls version): golang.org/x/tools/gopls v0.16.1

Additional context
I suppose ComponentScript needs to be rendered before its used, however it does not accept nil values.

I imagine the solution would be to accept nil ComponentScript but ignore them.

[joerdav]

Thanks for raising! I agree that this is unexpected behaviour. And the reasoning is because the order of operations is:

• Render all scripts referenced by the elements attributes (if not already rendered)
• Render <div open tag
• Render attributes coditionally

So I think the solution needs to be that we modify the generated code so that the conditional is evaluated earlier and used to inform both the rendering of scripts and the rendering of attributes.