Alternate syntax for cross references (#9116)

* Add support for local vs. remote xrefs

* Add doc for references

* Docs: fix cases not currently supported

* One more doc fix

* Doc: mentions for teams and orgs

* Change !num ref concept, no change in functionality

* Fix test

* Improve table of issue reference types

* Fix paragraph mark

docs/content/doc/usage/linked-references.en-us.md

@@ -0,0 +1,173 @@
+---
+date: "2019-11-21T17:00:00-03:00"
+title: "Usage: Automatically Linked References"
+slug: "automatically-linked-references"
+weight: 15
+toc: true
+draft: false
+menu:
+  sidebar:
+    parent: "usage"
+    name: "Automatically Linked References"
+    weight: 15
+    identifier: "automatically-linked-references"
+---
+
+# Automatically Linked References in Issues, Pull Requests and Commit Messages
+
+When an issue, pull request or comment is posted, the text description is parsed
+in search for references. These references will be shown as links in the Issue View
+and, in some cases, produce certain _actions_.
+
+Likewise, commit messages are parsed when they are listed, and _actions_
+are can be triggered when they are pushed to the main branch.
+
+To prevent the creation of unintended references, there are certain rules
+for them to be recognized. For example, they should not be included inside code
+text. They should also be reasonably cleared from their surrounding text
+(for example, using spaces).
+
+## User, Team and Organization Mentions
+
+When a text in the form `@username` is found and `username` matches the name
+of an existing user, a _mention_ reference is created. This will be shown
+by changing the text into a link to said user's profile, and possibly create
+a notification for the mentioned user depending on whether they have
+the necessary permission to access the contents.
+
+Example:
+
+> [@John](#), can you give this a look?
+
+This is also valid for teams and organizations:
+
+> [@Documenters](#), we need to plan for this.
+
+> [@CoolCompanyInc](#), this issue concerns us all!
+
+Teams will receive mail notifications when appropriate, but whole organizations won't.
+
+Commit messages do not produce user notifications.
+
+## Commits
+
+Commits can be referenced using their SHA1 hash, or a portion of it of
+at least seven characters. They will be shown as a link to the corresponding
+commit.
+
+Example:
+
+> This bug was introduced in [e59ff077](#)
+
+## Issues and Pull Requests
+
+A reference to another issue or pull request can be created using the simple
+notation `#1234`, where _1234_ is the number of an issue or pull request
+in the same repository. These references will be shown as links to the
+referenced content.
+
+The effect of creating this type of reference is that a _notice_ will be
+created in the referenced document, provided the creator of the reference
+has reading permissions on it.
+
+Example:
+
+> This seems related to [#1234](#)
+
+Issues and pull requests in other repositories can be referred to as well
+using the form `owner/repository#1234`:
+
+> This seems related to [mike/compiler#1234](#)
+
+Alternatively, the `!1234` notation can be used as well. Even when in Gitea
+a pull request is a form of issue, the `#1234` form will always link to
+an issue; if the linked entry happens to be a pull request instead, Gitea
+will redirect as appropriate. With the `!1234` notation, a pull request
+link will be created, which will be redirected to an issue if required.
+However, this distinction could be important if an external tracker is
+used, where links to issues and pull requests are not interchangeable.
+
+## Actionable References in Pull Requests and Commit Messages
+
+Sometimes a commit or pull request may fix or bring back a problem documented
+in a particular issue. Gitea supports closing and reopening the referenced
+issues by preceding the reference with a particular _keyword_. Common keywords
+include "closes", "fixes", "reopens", etc. This list can be
+[customized]({{< ref "/doc/advanced/config-cheat-sheet.en-us.md" >}}) by the
+site administrator.
+
+Example:
+
+> This PR _closes_ [#1234](#)
+
+If the actionable reference is accepted, this will create a notice on the
+referenced issue announcing that it will be closed when the referencing PR
+is merged.
+
+For an actionable reference to be accepted, _at least one_ of the following
+conditions must be met:
+
+* The commenter has permissions to close or reopen the issue at the moment
+of creating the reference.
+* The reference is inside a commit message.
+* The reference is posted as part of the pull request description.
+
+In the last case, the issue will be closed or reopened only if the merger
+of the pull request has permissions to do so.
+
+Additionally, only pull requests and commit messages can create an action,
+and only issues can be closed or reopened this way.
+
+The default _keywords_ are:
+
+* **Closing**: close, closes, closed, fix, fixes, fixed, resolve, resolves, resolved
+* **Reopening**: reopen, reopens, reopened
+
+## External Trackers
+
+Gitea supports the use of external issue trackers, and references to issues
+hosted externally can be created in pull requests. However, if the external
+tracker uses numbers to identify issues, they will be indistinguishable from
+the pull requests hosted in Gitea. To address this, Gitea allows the use of
+the `!` marker to identify pull requests. For example:
+
+> This is issue [#1234](#), and links to the external tracker.
+
+> This is pull request [!1234](#), and links to a pull request in Gitea.
+
+The `!` and `#` can be used interchangeably for issues and pull request _except_
+for this case, where a distinction is required.
+
+## Issues and Pull Requests References Summary
+
+This table illustrates the different kinds of cross-reference for issues and pull requests.
+In the examples, `User1/Repo1` refers to the repository where the reference is used, while
+`UserZ/RepoZ` indicates a different repository.
+
+| Reference in User1/Repo1  | Repo1 issues are external | RepoZ issues are external | Should render                    |
+|---------------------------|:-------------------------:|:-------------------------:|----------------------------------|
+| `#1234`                   |     no                    |    N/A                    | A link to issue/pull 1234 in `User1/Repo1` |
+| `!1234`                   |     no                    |    N/A                    | A link to issue/pull 1234 in `User1/Repo1` |
+| `#1234`                   |    yes                    |    N/A                    | A link to _external issue_ 1234 for `User1/Repo1` |
+| `!1234`                   |    yes                    |    N/A                    | A link to _PR_ 1234 for `User1/Repo1` |
+| `User1/Repo1#1234`        |     no                    |    N/A                    | A link to issue/pull 1234 in `User1/Repo1` |
+| `User1/Repo1!1234`        |     no                    |    N/A                    | A link to issue/pull 1234 in `User1/Repo1` |
+| `User1/Repo1#1234`        |    yes                    |    N/A                    | A link to _external issue_ 1234 for `User1/Repo1` |
+| `User1/Repo1!1234`        |    yes                    |    N/A                    | A link to _PR_ 1234 for `User1/Repo1` |
+| `UserZ/RepoZ#1234`        |    N/A                    |     no                    | A link to issue/pull 1234 in `UserZ/RepoZ` |
+| `UserZ/RepoZ!1234`        |    N/A                    |     no                    | A link to issue/pull 1234 in `UserZ/RepoZ` |
+| _Not supported_           |    N/A                    |    yes                    | A link to _external issue_ 1234 for `UserZ/RepoZ` |
+| `UserZ/RepoZ!1234`        |    N/A                    |    yes                    | A link to _PR_ 1234 for `UserZ/RepoZ` |
+| **Alphanumeric issue IDs:** | -                       | -                         | - |
+| `AAA-1234`                |    yes                    |    N/A                    | A link to _external issue_ `AAA-1234` for `User1/Repo1` |
+| `!1234`                   |    yes                    |    N/A                    | A link to _PR_ 1234 for `User1/Repo1` |
+| `User1/Repo1!1234`        |    yes                    |    N/A                    | A link to _PR_ 1234 for `User1/Repo1` |
+| _Not supported_           |    N/A                    |    yes                    | A link to _external issue_ `AAA-1234` for `UserZ/RepoZ` |
+| `UserZ/RepoZ!1234`        |    N/A                    |    yes                    | A link to _PR_ 1234 in `UserZ/RepoZ` |
+
+_The last section is for repositories with external issue trackers that use alphanumeric format._
+
+_**N/A**: not applicable._
+
+Note: automatic references between repositories with different types of issues (external vs. internal) are not fully supported
+and may render invalid links.

modules/markup/html.go

@@ -640,24 +640,42 @@ func issueIndexPatternProcessor(ctx *postProcessCtx, node *html.Node) {
 		ref   *references.RenderizableReference
 	)
 
-	if ctx.metas["style"] == IssueNameStyleAlphanumeric {
-		found, ref = references.FindRenderizableReferenceAlphanumeric(node.Data)
-	} else {
-		found, ref = references.FindRenderizableReferenceNumeric(node.Data)
+	_, exttrack := ctx.metas["format"]
+	alphanum := ctx.metas["style"] == IssueNameStyleAlphanumeric
+
+	// Repos with external issue trackers might still need to reference local PRs
+	// We need to concern with the first one that shows up in the text, whichever it is
+	found, ref = references.FindRenderizableReferenceNumeric(node.Data, exttrack && alphanum)
+	if exttrack && alphanum {
+		if found2, ref2 := references.FindRenderizableReferenceAlphanumeric(node.Data); found2 {
+			if !found || ref2.RefLocation.Start < ref.RefLocation.Start {
+				found = true
+				ref = ref2
+			}
+		}
 	}
 	if !found {
 		return
 	}
 
 	var link *html.Node
 	reftext := node.Data[ref.RefLocation.Start:ref.RefLocation.End]
-	if _, ok := ctx.metas["format"]; ok {
+	if exttrack && !ref.IsPull {
 		ctx.metas["index"] = ref.Issue
 		link = createLink(com.Expand(ctx.metas["format"], ctx.metas), reftext, "issue")
-	} else if ref.Owner == "" {
-		link = createLink(util.URLJoin(setting.AppURL, ctx.metas["user"], ctx.metas["repo"], "issues", ref.Issue), reftext, "issue")
 	} else {
-		link = createLink(util.URLJoin(setting.AppURL, ref.Owner, ref.Name, "issues", ref.Issue), reftext, "issue")
+		// Path determines the type of link that will be rendered. It's unknown at this point whether
+		// the linked item is actually a PR or an issue. Luckily it's of no real consequence because
+		// Gitea will redirect on click as appropriate.
+		path := "issues"
+		if ref.IsPull {
+			path = "pulls"
+		}
+		if ref.Owner == "" {
+			link = createLink(util.URLJoin(setting.AppURL, ctx.metas["user"], ctx.metas["repo"], path, ref.Issue), reftext, "issue")
+		} else {
+			link = createLink(util.URLJoin(setting.AppURL, ref.Owner, ref.Name, path, ref.Issue), reftext, "issue")
+		}
 	}
 
 	if ref.Action == references.XRefActionNone {
@@ -667,7 +685,7 @@ func issueIndexPatternProcessor(ctx *postProcessCtx, node *html.Node) {
 
 	// Decorate action keywords if actionable
 	var keyword *html.Node
-	if references.IsXrefActionable(ref.Action) {
+	if references.IsXrefActionable(ref, exttrack, alphanum) {
 		keyword = createKeyword(node.Data[ref.ActionLocation.Start:ref.ActionLocation.End])
 	} else {
 		keyword = &html.Node{

modules/markup/html_internal_test.go

@@ -25,8 +25,8 @@ func alphanumIssueLink(baseURL, class, name string) string {
 }
 
 // numericLink an HTML to a numeric-style issue
-func numericIssueLink(baseURL, class string, index int) string {
-	return link(util.URLJoin(baseURL, strconv.Itoa(index)), class, fmt.Sprintf("#%d", index))
+func numericIssueLink(baseURL, class string, index int, marker string) string {
+	return link(util.URLJoin(baseURL, strconv.Itoa(index)), class, fmt.Sprintf("%s%d", marker, index))
 }
 
 // link an HTML link
@@ -75,8 +75,12 @@ func TestRender_IssueIndexPattern(t *testing.T) {
 	test("#abcd")
 	test("test#1234")
 	test("#1234test")
-	test(" test #1234test")
+	test("#abcd")
+	test("test!1234")
+	test("!1234test")
+	test(" test !1234test")
 	test("/home/gitea/#1234")
+	test("/home/gitea/!1234")
 
 	// should not render issue mention without leading space
 	test("test#54321 issue")
@@ -90,42 +94,54 @@ func TestRender_IssueIndexPattern2(t *testing.T) {
 	setting.AppSubURL = AppSubURL
 
 	// numeric: render inputs with valid mentions
-	test := func(s, expectedFmt string, indices ...int) {
+	test := func(s, expectedFmt, marker string, indices ...int) {
+		var path, prefix string
+		if marker == "!" {
+			path = "pulls"
+			prefix = "http://localhost:3000/someUser/someRepo/pulls/"
+		} else {
+			path = "issues"
+			prefix = "https://someurl.com/someUser/someRepo/"
+		}
+
 		links := make([]interface{}, len(indices))
 		for i, index := range indices {
-			links[i] = numericIssueLink(util.URLJoin(setting.AppSubURL, "issues"), "issue", index)
+			links[i] = numericIssueLink(util.URLJoin(setting.AppSubURL, path), "issue", index, marker)
 		}
 		expectedNil := fmt.Sprintf(expectedFmt, links...)
 		testRenderIssueIndexPattern(t, s, expectedNil, &postProcessCtx{metas: localMetas})
 
 		for i, index := range indices {
-			links[i] = numericIssueLink("https://someurl.com/someUser/someRepo/", "issue", index)
+			links[i] = numericIssueLink(prefix, "issue", index, marker)
 		}
 		expectedNum := fmt.Sprintf(expectedFmt, links...)
 		testRenderIssueIndexPattern(t, s, expectedNum, &postProcessCtx{metas: numericMetas})
 	}
 
 	// should render freestanding mentions
-	test("#1234 test", "%s test", 1234)
-	test("test #8 issue", "test %s issue", 8)
-	test("test issue #1234", "test issue %s", 1234)
-	test("fixes issue #1234.", "fixes issue %s.", 1234)
+	test("#1234 test", "%s test", "#", 1234)
+	test("test #8 issue", "test %s issue", "#", 8)
+	test("!1234 test", "%s test", "!", 1234)
+	test("test !8 issue", "test %s issue", "!", 8)
+	test("test issue #1234", "test issue %s", "#", 1234)
+	test("fixes issue #1234.", "fixes issue %s.", "#", 1234)
 
 	// should render mentions in parentheses / brackets
-	test("(#54321 issue)", "(%s issue)", 54321)
-	test("[#54321 issue]", "[%s issue]", 54321)
-	test("test (#9801 extra) issue", "test (%s extra) issue", 9801)
-	test("test (#1)", "test (%s)", 1)
+	test("(#54321 issue)", "(%s issue)", "#", 54321)
+	test("[#54321 issue]", "[%s issue]", "#", 54321)
+	test("test (#9801 extra) issue", "test (%s extra) issue", "#", 9801)
+	test("test (!9801 extra) issue", "test (%s extra) issue", "!", 9801)
+	test("test (#1)", "test (%s)", "#", 1)
 
 	// should render multiple issue mentions in the same line
-	test("#54321 #1243", "%s %s", 54321, 1243)
-	test("wow (#54321 #1243)", "wow (%s %s)", 54321, 1243)
-	test("(#4)(#5)", "(%s)(%s)", 4, 5)
-	test("#1 (#4321) test", "%s (%s) test", 1, 4321)
+	test("#54321 #1243", "%s %s", "#", 54321, 1243)
+	test("wow (#54321 #1243)", "wow (%s %s)", "#", 54321, 1243)
+	test("(#4)(#5)", "(%s)(%s)", "#", 4, 5)
+	test("#1 (#4321) test", "%s (%s) test", "#", 1, 4321)
 
 	// should render with :
-	test("#1234: test", "%s: test", 1234)
-	test("wow (#54321: test)", "wow (%s: test)", 54321)
+	test("#1234: test", "%s: test", "#", 1234)
+	test("wow (#54321: test)", "wow (%s: test)", "#", 54321)
 }
 
 func TestRender_IssueIndexPattern3(t *testing.T) {
@@ -201,7 +217,7 @@ func TestRender_AutoLink(t *testing.T) {
 
 	// render valid issue URLs
 	test(util.URLJoin(setting.AppSubURL, "issues", "3333"),
-		numericIssueLink(util.URLJoin(setting.AppSubURL, "issues"), "issue", 3333))
+		numericIssueLink(util.URLJoin(setting.AppSubURL, "issues"), "issue", 3333, "#"))
 
 	// render valid commit URLs
 	tmp := util.URLJoin(AppSubURL, "commit", "d8a994ef243349f321568f9e36d5c3f444b99cae")