x/pkgsite: examples not rendered according to the testing documentation; includes unwanted code

[kortschak]

What is the URL of the page with the issue?

https://pkg.go.dev/gonum.org/v1/gonum/graph/community#example-Profile-Simple

What is your user agent?

Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:84.0) Gecko/20100101 Firefox/84.0

Screenshot

What did you do?

Navigate to the linked example.

What did you expect to see?

According to the testing documentation

The entire test file is presented as the example when it contains a single example function, at least one other function, type, variable, or constant declaration, and no test or benchmark functions.

I expect to see just the body of the example as rendered on godoc.org since there is more than one example in the file.

// Profile calls Modularize which implements the Louvain modularization algorithm.
// Since this is a randomized algorithm we use a defined random source to ensure
// consistency between test runs. In practice, results will not differ greatly
// between runs with different PRNG seeds.
src := rand.NewSource(1)

// Create dumbell graph:
//
//  0       4
//  |\     /|
//  | 2 - 3 |
//  |/     \|
//  1       5
//
g := simple.NewUndirectedGraph()
for u, e := range smallDumbell {
    for v := range e {
        g.SetEdge(simple.Edge{F: simple.Node(u), T: simple.Node(v)})
    }
}

// Get the profile of internal node weight for resolutions
// between 0.1 and 10 using logarithmic bisection.
p, err := community.Profile(
    community.ModularScore(g, community.Weight, 10, src),
    true, 1e-3, 0.1, 10,
)
if err != nil {
    log.Fatal(err)
}

// Print out each step with communities ordered.
for _, d := range p {
    comm := d.Communities()
    for _, c := range comm {
        sort.Sort(ordered.ByID(c))
    }
    sort.Sort(ordered.BySliceIDs(comm))
    fmt.Printf("Low:%.2v High:%.2v Score:%v Communities:%v Q=%.3v\n",
        d.Low, d.High, d.Score, comm, community.Q(g, comm, d.Low))
}

What did you see instead?

Extraneous details also presented (and the imports mangled and helpful comments removed).

package main

import (
	"fmt"
	"golang.org/x/exp/rand"
	"gonum.org/v1/gonum/graph/community"
	"gonum.org/v1/gonum/graph/internal/ordered"
	"gonum.org/v1/gonum/graph/simple"
	"log"
	"sort"
)

func main() {
	// Profile calls Modularize which implements the Louvain modularization algorithm.
	// Since this is a randomized algorithm we use a defined random source to ensure
	// consistency between test runs. In practice, results will not differ greatly
	// between runs with different PRNG seeds.
	src := rand.NewSource(1)

	// Create dumbell graph:
	//
	//  0       4
	//  |\     /|
	//  | 2 - 3 |
	//  |/     \|
	//  1       5
	//
	g := simple.NewUndirectedGraph()
	for u, e := range smallDumbell {
		for v := range e {
			g.SetEdge(simple.Edge{F: simple.Node(u), T: simple.Node(v)})
		}
	}

	// Get the profile of internal node weight for resolutions
	// between 0.1 and 10 using logarithmic bisection.
	p, err := community.Profile(
		community.ModularScore(g, community.Weight, 10, src),
		true, 1e-3, 0.1, 10,
	)
	if err != nil {
		log.Fatal(err)
	}

	// Print out each step with communities ordered.
	for _, d := range p {
		comm := d.Communities()
		for _, c := range comm {
			sort.Sort(ordered.ByID(c))
		}
		sort.Sort(ordered.BySliceIDs(comm))
		fmt.Printf("Low:%.2v High:%.2v Score:%v Communities:%v Q=%.3v\n",
			d.Low, d.High, d.Score, comm, community.Q(g, comm, d.Low))
	}

}

// intset is an integer set.
type intset map[int]struct{}

func linksTo(i ...int) intset {
	if len(i) == 0 {
		return nil
	}
	s := make(intset)
	for _, v := range i {
		s[v] = struct{}{}
	}
	return s
}

var (
	smallDumbell = []intset{
		0: linksTo(1, 2),
		1: linksTo(2),
		2: linksTo(3),
		3: linksTo(4, 5),
		4: linksTo(5),
		5: nil,
	}

	middleEast = struct{ friends, complicated, enemies []intset }{

		friends: []intset{
			0:  nil,
			1:  linksTo(5, 7, 9, 12),
			2:  linksTo(11),
			3:  linksTo(4, 5, 10),
			4:  linksTo(3, 5, 10),
			5:  linksTo(1, 3, 4, 8, 10, 12),
			6:  nil,
			7:  linksTo(1, 12),
			8:  linksTo(5, 9, 11),
			9:  linksTo(1, 8, 12),
			10: linksTo(3, 4, 5),
			11: linksTo(2, 8),
			12: linksTo(1, 5, 7, 9),
		},

		complicated: []intset{
			0:  linksTo(2, 4),
			1:  linksTo(4, 8),
			2:  linksTo(0, 3, 4, 5, 8, 9),
			3:  linksTo(2, 8, 11),
			4:  linksTo(0, 1, 2, 8),
			5:  linksTo(2),
			6:  nil,
			7:  linksTo(9, 11),
			8:  linksTo(1, 2, 3, 4, 10, 12),
			9:  linksTo(2, 7, 11),
			10: linksTo(8),
			11: linksTo(3, 7, 9, 12),
			12: linksTo(8, 11),
		},

		enemies: []intset{
			0:  linksTo(1, 3, 5, 6, 7, 8, 9, 10, 11, 12),
			1:  linksTo(0, 2, 3, 6, 10, 11),
			2:  linksTo(1, 6, 7, 10, 12),
			3:  linksTo(0, 1, 6, 7, 9, 12),
			4:  linksTo(6, 7, 9, 11, 12),
			5:  linksTo(0, 6, 7, 9, 11),
			6:  linksTo(0, 1, 2, 3, 4, 5, 7, 8, 9, 10, 11, 12),
			7:  linksTo(0, 2, 3, 4, 5, 6, 8, 10),
			8:  linksTo(0, 6, 7),
			9:  linksTo(0, 3, 4, 5, 6, 10),
			10: linksTo(0, 1, 2, 6, 7, 9, 11, 12),
			11: linksTo(0, 1, 4, 5, 6, 10),
			12: linksTo(0, 2, 3, 4, 6, 10),
		},
	}
)

The parts included are used by the second example and so entirely unrelated to the first. The choice of including two examples in the file was specifically to prevent these details leaking to the reader since they do not help advance the documentation.