Add codeowners feature (#24910)

Hello.
This PR adds a github like configuration for the CODEOWNERS file.

Resolves: #10161

1 files changed, 221 insertions, 0 deletions

diff --git a/models/issues/pull.go b/models/issues/pull.go
index 3f37d8d243..63bc258d2f 100644
--- a/models/issues/pull.go
+++ b/models/issues/pull.go
@@ -8,11 +8,13 @@ import (
 	"context"
 	"fmt"
 	"io"
+	"regexp"
 	"strconv"
 	"strings"
 
 	"code.gitea.io/gitea/models/db"
 	git_model "code.gitea.io/gitea/models/git"
+	org_model "code.gitea.io/gitea/models/organization"
 	pull_model "code.gitea.io/gitea/models/pull"
 	repo_model "code.gitea.io/gitea/models/repo"
 	user_model "code.gitea.io/gitea/models/user"
@@ -887,3 +889,222 @@ func MergeBlockedByOfficialReviewRequests(ctx context.Context, protectBranch *gi
 func MergeBlockedByOutdatedBranch(protectBranch *git_model.ProtectedBranch, pr *PullRequest) bool {
 	return protectBranch.BlockOnOutdatedBranch && pr.CommitsBehind > 0
 }
+
+func PullRequestCodeOwnersReview(ctx context.Context, pull *Issue, pr *PullRequest) error {
+	files := []string{"CODEOWNERS", "docs/CODEOWNERS", ".gitea/CODEOWNERS"}
+
+	if pr.IsWorkInProgress() {
+		return nil
+	}
+
+	if err := pr.LoadBaseRepo(ctx); err != nil {
+		return err
+	}
+
+	repo, err := git.OpenRepository(ctx, pr.BaseRepo.RepoPath())
+	if err != nil {
+		return err
+	}
+	defer repo.Close()
+
+	branch, err := repo.GetDefaultBranch()
+	if err != nil {
+		return err
+	}
+
+	commit, err := repo.GetBranchCommit(branch)
+	if err != nil {
+		return err
+	}
+
+	var data string
+	for _, file := range files {
+		if blob, err := commit.GetBlobByPath(file); err == nil {
+			data, err = blob.GetBlobContent()
+			if err == nil {
+				break
+			}
+		}
+	}
+
+	rules, _ := GetCodeOwnersFromContent(ctx, data)
+	changedFiles, err := repo.GetFilesChangedBetween(git.BranchPrefix+pr.BaseBranch, pr.GetGitRefName())
+	if err != nil {
+		return err
+	}
+
+	uniqUsers := make(map[int64]*user_model.User)
+	uniqTeams := make(map[string]*org_model.Team)
+	for _, rule := range rules {
+		for _, f := range changedFiles {
+			if (rule.Rule.MatchString(f) && !rule.Negative) || (!rule.Rule.MatchString(f) && rule.Negative) {
+				for _, u := range rule.Users {
+					uniqUsers[u.ID] = u
+				}
+				for _, t := range rule.Teams {
+					uniqTeams[fmt.Sprintf("%d/%d", t.OrgID, t.ID)] = t
+				}
+			}
+		}
+	}
+
+	for _, u := range uniqUsers {
+		if u.ID != pull.Poster.ID {
+			if _, err := AddReviewRequest(pull, u, pull.Poster); err != nil {
+				log.Warn("Failed add assignee user: %s to PR review: %s#%d, error: %s", u.Name, pr.BaseRepo.Name, pr.ID, err)
+				return err
+			}
+		}
+	}
+	for _, t := range uniqTeams {
+		if _, err := AddTeamReviewRequest(pull, t, pull.Poster); err != nil {
+			log.Warn("Failed add assignee team: %s to PR review: %s#%d, error: %s", t.Name, pr.BaseRepo.Name, pr.ID, err)
+			return err
+		}
+	}
+
+	return nil
+}
+
+// GetCodeOwnersFromContent returns the code owners configuration
+// Return empty slice if files missing
+// Return warning messages on parsing errors
+// We're trying to do the best we can when parsing a file.
+// Invalid lines are skipped. Non-existent users and teams too.
+func GetCodeOwnersFromContent(ctx context.Context, data string) ([]*CodeOwnerRule, []string) {
+	if len(data) == 0 {
+		return nil, nil
+	}
+
+	rules := make([]*CodeOwnerRule, 0)
+	lines := strings.Split(data, "\n")
+	warnings := make([]string, 0)
+
+	for i, line := range lines {
+		tokens := TokenizeCodeOwnersLine(line)
+		if len(tokens) == 0 {
+			continue
+		} else if len(tokens) < 2 {
+			warnings = append(warnings, fmt.Sprintf("Line: %d: incorrect format", i+1))
+			continue
+		}
+		rule, wr := ParseCodeOwnersLine(ctx, tokens)
+		for _, w := range wr {
+			warnings = append(warnings, fmt.Sprintf("Line: %d: %s", i+1, w))
+		}
+		if rule == nil {
+			continue
+		}
+
+		rules = append(rules, rule)
+	}
+
+	return rules, warnings
+}
+
+type CodeOwnerRule struct {
+	Rule     *regexp.Regexp
+	Negative bool
+	Users    []*user_model.User
+	Teams    []*org_model.Team
+}
+
+func ParseCodeOwnersLine(ctx context.Context, tokens []string) (*CodeOwnerRule, []string) {
+	var err error
+	rule := &CodeOwnerRule{
+		Users:    make([]*user_model.User, 0),
+		Teams:    make([]*org_model.Team, 0),
+		Negative: strings.HasPrefix(tokens[0], "!"),
+	}
+
+	warnings := make([]string, 0)
+
+	rule.Rule, err = regexp.Compile(fmt.Sprintf("^%s$", strings.TrimPrefix(tokens[0], "!")))
+	if err != nil {
+		warnings = append(warnings, fmt.Sprintf("incorrect codeowner regexp: %s", err))
+		return nil, warnings
+	}
+
+	for _, user := range tokens[1:] {
+		user = strings.TrimPrefix(user, "@")
+
+		// Only @org/team can contain slashes
+		if strings.Contains(user, "/") {
+			s := strings.Split(user, "/")
+			if len(s) != 2 {
+				warnings = append(warnings, fmt.Sprintf("incorrect codeowner group: %s", user))
+				continue
+			}
+			orgName := s[0]
+			teamName := s[1]
+
+			org, err := org_model.GetOrgByName(ctx, orgName)
+			if err != nil {
+				warnings = append(warnings, fmt.Sprintf("incorrect codeowner organization: %s", user))
+				continue
+			}
+			teams, err := org.LoadTeams()
+			if err != nil {
+				warnings = append(warnings, fmt.Sprintf("incorrect codeowner team: %s", user))
+				continue
+			}
+
+			for _, team := range teams {
+				if team.Name == teamName {
+					rule.Teams = append(rule.Teams, team)
+				}
+			}
+		} else {
+			u, err := user_model.GetUserByName(ctx, user)
+			if err != nil {
+				warnings = append(warnings, fmt.Sprintf("incorrect codeowner user: %s", user))
+				continue
+			}
+			rule.Users = append(rule.Users, u)
+		}
+	}
+
+	if (len(rule.Users) == 0) && (len(rule.Teams) == 0) {
+		warnings = append(warnings, "no users/groups matched")
+		return nil, warnings
+	}
+
+	return rule, warnings
+}
+
+func TokenizeCodeOwnersLine(line string) []string {
+	if len(line) == 0 {
+		return nil
+	}
+
+	line = strings.TrimSpace(line)
+	line = strings.ReplaceAll(line, "\t", " ")
+
+	tokens := make([]string, 0)
+
+	escape := false
+	token := ""
+	for _, char := range line {
+		if escape {
+			token += string(char)
+			escape = false
+		} else if string(char) == "\\" {
+			escape = true
+		} else if string(char) == "#" {
+			break
+		} else if string(char) == " " {
+			if len(token) > 0 {
+				tokens = append(tokens, token)
+				token = ""
+			}
+		} else {
+			token += string(char)
+		}
+	}
+
+	if len(token) > 0 {
+		tokens = append(tokens, token)
+	}
+
+	return tokens
+}