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link GH- reference
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@rhysd
rhysd committed Oct 5, 2024
1 parent 0df350a commit 249bbd1
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Showing 2 changed files with 101 additions and 12 deletions.
82 changes: 70 additions & 12 deletions reflink.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,7 @@ import (
"fmt"
"net/url"
"regexp"
"sort"
"strings"

"github.com/yuin/goldmark"
Expand All @@ -21,6 +22,12 @@ type refLink struct {
text string
}

type byStart []refLink

func (l byStart) Len() int { return len(l) }
func (l byStart) Swap(i, j int) { l[i], l[j] = l[j], l[i] }
func (l byStart) Less(i, j int) bool { return l[i].start < l[j].start }

// Note: '_' is actually not boundary. But it's hard to check if the '_' is a part of italic/bold
// syntax.
// For example, _#123_ should be linked because '_'s are part of italic syntax. But _#123 and #123_
Expand All @@ -42,11 +49,18 @@ func isUserNameChar(b byte) bool {
return '0' <= b && b <= '9' || 'a' <= b && b <= 'z' || 'A' <= b && b <= 'Z' || b == '-'
}

type extRef struct {
prefix string
pat *regexp.Regexp
url string
}

// Reflinker detects all references in markdown text and replaces them with links.
type Reflinker struct {
repo string
home string
src []byte
ext []extRef
links []refLink
}

Expand All @@ -59,12 +73,14 @@ func NewReflinker(repoURL string, src []byte) *Reflinker {
}
u.Path = ""

return &Reflinker{
l := &Reflinker{
repo: repoURL,
home: u.String(),
src: src,
links: nil,
}
l.AddExtRef("GH-", repoURL+"/issues/<num>", false)
return l
}

func (l *Reflinker) isBoundaryAt(idx int) bool {
Expand Down Expand Up @@ -97,7 +113,7 @@ func (l *Reflinker) lastIndexIssueRef(begin, end int) int {
return end // The text ends with issue number
}

func (l *Reflinker) linkIssue(begin, end int) int {
func (l *Reflinker) linkIssueRef(begin, end int) int {
e := l.lastIndexIssueRef(begin, end)
if e < 0 {
return begin + 1
Expand All @@ -107,7 +123,8 @@ func (l *Reflinker) linkIssue(begin, end int) int {
l.links = append(l.links, refLink{
start: begin,
end: e,
text: fmt.Sprintf("[%s](%s/issues/%s)", r, l.repo, r[1:]),
// Note: The link may be for PR, but GitHub can redirect this issue link to the PR
text: fmt.Sprintf("[%s](%s/issues/%s)", r, l.repo, r[1:]),
})

return e
Expand Down Expand Up @@ -149,7 +166,7 @@ func (l *Reflinker) lastIndexUserRef(begin, end int) int {
return end
}

func (l *Reflinker) linkUser(begin, end int) int {
func (l *Reflinker) linkUserRef(begin, end int) int {
e := l.lastIndexUserRef(begin, end)
if e < 0 {
return begin + 1
Expand Down Expand Up @@ -200,18 +217,57 @@ func (l *Reflinker) linkGitHubRefs(t *ast.Text) {
if i < 0 || len(s)-1 <= i {
return
}

switch s[i] {
case '#':
o = l.linkIssue(o+i, t.Segment.Stop)
o = l.linkIssueRef(o+i, t.Segment.Stop)
case '@':
o = l.linkUser(o+i, t.Segment.Stop)
o = l.linkUserRef(o+i, t.Segment.Stop)
default:
// hex character [0-9a-f]
o = l.linkCommitSHA(o+i, t.Segment.Stop)
}
}
}

// Parameters are corresponding to the API:
// https://docs.github.com/en/rest/repos/autolinks?apiVersion=2022-11-28
func (l *Reflinker) AddExtRef(prefix, url string, alphanumeric bool) {
var r *regexp.Regexp
if alphanumeric {
r = regexp.MustCompile(`\b` + prefix + `[a-zA-Z0-9_]+`)
} else {
r = regexp.MustCompile(`\b` + prefix + `\d+\b`)
}
l.ext = append(l.ext, extRef{prefix, r, url})
}

func (l *Reflinker) linkExtRef(start, end int) int {
src := l.src[start:end]
for _, ext := range l.ext {
if r := ext.pat.FindIndex(src); r != nil {
s, e := r[0], r[1]
ref := src[s:e]
num := ref[len(ext.prefix):]
url := strings.ReplaceAll(ext.url, "<num>", string(num))
l.links = append(l.links, refLink{
start: start + s,
end: start + e,
text: fmt.Sprintf("[%s](%s)", ref, url),
})
return start + e
}
}
return end // Not found
}

func (l *Reflinker) linkExtRefs(t *ast.Text) {
o := t.Segment.Start
for o < t.Segment.Stop-1 {
o = l.linkExtRef(o, t.Segment.Stop)
}
}

// Commit URL with fragment should not be converted to a reference link.
// e.g. https://github.com/rhysd/changelog-from-release/commit/096c8152092281371e88265dd43b1b7d23a88453#diff-ced928ba39db1f56ef7862baebfe0314ed06f433a71defdc60a2b12e67011453L226
var reGitHubCommitPath = regexp.MustCompile(`^/([^/]+/[^/]+)/commit/([[:xdigit:]]{7,})$`)
Expand Down Expand Up @@ -271,7 +327,7 @@ func (l *Reflinker) linkIssueURL(m [][]byte, url []byte, start, end int) {
})
}

func (l *Reflinker) linkURL(n *ast.AutoLink, src []byte) {
func (l *Reflinker) linkURL(n *ast.AutoLink) {
start := 0
if p := n.PreviousSibling(); p != nil {
t := p.(*ast.Text)
Expand All @@ -282,27 +338,27 @@ func (l *Reflinker) linkURL(n *ast.AutoLink, src []byte) {
}

home := []byte(l.home)
url := n.URL(src)
url := n.URL(l.src)
if !bytes.HasPrefix(url, home) {
return
}

// Search the offset of the start of the URL. When the text is a child of some other node, URL
// may not appear just after the previous node. The example is **https://...** where URL appers
// after the first **.
offset := bytes.Index(src[start:], url)
offset := bytes.Index(l.src[start:], url)
if offset < 0 {
return
}
start += offset

end := start + len(url)
if start >= len(src) || end > len(src) {
if start >= len(l.src) || end > len(l.src) {
return
}

// Note: `end` is the index of the character just after the URL
if start > 0 && src[start-1] == '<' && end < len(src) && src[end] == '>' {
if start > 0 && l.src[start-1] == '<' && end < len(l.src) && l.src[end] == '>' {
return
}

Expand All @@ -320,6 +376,7 @@ func (l *Reflinker) BuildLinkedText() string {
if len(l.links) == 0 {
return string(l.src)
}
sort.Sort(byStart(l.links))

var b strings.Builder
i := 0
Expand Down Expand Up @@ -353,10 +410,11 @@ func LinkRefs(input string, repoURL string) string {
case *ast.CodeSpan, *ast.Link:
return ast.WalkSkipChildren, nil
case *ast.AutoLink:
l.linkURL(n, src)
l.linkURL(n)
return ast.WalkSkipChildren, nil
case *ast.Text:
l.linkGitHubRefs(n)
l.linkExtRefs(n)
return ast.WalkContinue, nil
default:
return ast.WalkContinue, nil
Expand Down
31 changes: 31 additions & 0 deletions reflink_test.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -531,6 +531,37 @@ func TestLinkRefs(t *testing.T) {
input: "the PR review is https://github.com/u/r/pull/123#pullrequestreview-1212591132",
want: "the PR review is [#123 (review)](https://github.com/u/r/pull/123#pullrequestreview-1212591132)",
},
{
what: "GitHub external reference in text",
input: "This is GH-123 link",
want: "This is [GH-123](https://github.com/u/r/issues/123) link",
},
{
what: "GitHub external reference only",
input: "GH-123",
want: "[GH-123](https://github.com/u/r/issues/123)",
},
{
what: "GitHub external reference inside URL",
input: "https://example.com/GH-123/foo",
want: "https://example.com/GH-123/foo",
},
{
what: "alphabets following GitHub external reference",
input: "This is GH-123abc",
want: "This is GH-123abc",
},
{
what: "alphabets in GitHub external reference",
input: "This is GH-abc",
want: "This is GH-abc",
},
{
what: "GHE external reference",
input: "This is GH-123 link",
want: "This is [GH-123](https://github.company.com/a/b/issues/123) link",
repoURL: "https://github.company.com/a/b",
},
}

for _, tc := range tests {
Expand Down

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