fix: avoid enumerating every public repository in issue search (#38992) (#39000)

Backport #38992 by @lunny

Both issue search endpoints resolve their repository filter with
`SearchRepositoryIDs` and pass the result to the indexer as `RepoIDs`.
They mean
to leave public repositories to the indexer, but
`SearchRepoOptions.AllPublic` is
only read when `OwnerID > 0`, so without an `owner` filter the flag does
nothing
and every public repository is enumerated, without a `LIMIT`, into
`repo_id IN (...)`.

Those IDs are redundant, as `allPublic` is passed to the indexer, which
already
matches every public repository. On a large instance this binds tens of
thousands
of parameters and can fail in the driver, making the endpoint return 500
for every
filter. Admins are worst hit, as `SearchRepositoryCondition` skips their
accessible-repository condition and enumerates the whole table.

Restrict the enumeration to private repositories. The result set is
unchanged, as
the dropped IDs are a subset of what `allPublic` matches.

Both endpoints held copies of this block, so it moves to
`routers/common`.

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

routers/api/v1/repo/issue.go

@@ -14,7 +14,6 @@ import (
 
 	"gitea.dev/models/db"
 	issues_model "gitea.dev/models/issues"
-	"gitea.dev/models/organization"
 	access_model "gitea.dev/models/perm/access"
 	repo_model "gitea.dev/models/repo"
 	"gitea.dev/models/unit"
@@ -33,61 +32,6 @@ import (
 	issue_service "gitea.dev/services/issue"
 )
 
-// buildSearchIssuesRepoIDs builds the list of repository IDs for issue search based on query parameters.
-// It returns repoIDs, allPublic flag, and any error that occurred.
-func buildSearchIssuesRepoIDs(ctx *context.APIContext) (repoIDs []int64, allPublic bool, err error) {
-	opts := repo_model.SearchRepoOptions{
-		Private:     false,
-		AllPublic:   true,
-		TopicOnly:   false,
-		Collaborate: optional.None[bool](),
-		// This needs to be a column that is not nil in fixtures or
-		// MySQL will return different results when sorting by null in some cases
-		OrderBy: db.SearchOrderByAlphabetically,
-		Actor:   ctx.Doer,
-	}
-	if ctx.IsSigned {
-		opts.Private = true
-		opts.AllLimited = true
-	}
-	opts.ApplyPublicOnly(ctx.PublicOnly)
-	if ctx.FormString("owner") != "" {
-		owner, err := user_model.GetUserByName(ctx, ctx.FormString("owner"))
-		if err != nil {
-			return nil, false, err
-		}
-		opts.OwnerID = owner.ID
-		opts.AllLimited = false
-		opts.AllPublic = false
-		opts.Collaborate = optional.Some(false)
-	}
-	if ctx.FormString("team") != "" {
-		if ctx.FormString("owner") == "" {
-			return nil, false, util.NewInvalidArgumentErrorf("owner organisation is required for filtering on team")
-		}
-		team, err := organization.GetTeam(ctx, opts.OwnerID, ctx.FormString("team"))
-		if err != nil {
-			return nil, false, err
-		}
-		opts.TeamID = team.ID
-	}
-
-	if opts.AllPublic {
-		allPublic = true
-		opts.AllPublic = false // set it false to avoid returning too many repos, we could filter by indexer
-	}
-	repoIDs, _, err = repo_model.SearchRepositoryIDs(ctx, opts)
-	if err != nil {
-		return nil, false, err
-	}
-	if len(repoIDs) == 0 {
-		// no repos found, don't let the indexer return all repos
-		repoIDs = []int64{0}
-	}
-
-	return repoIDs, allPublic, nil
-}
-
 // SearchIssues searches for issues across the repositories that the user has access to
 func SearchIssues(ctx *context.APIContext) {
 	// swagger:operation GET /repos/issues/search issue issueSearchIssues
@@ -193,7 +137,12 @@ func SearchIssues(ctx *context.APIContext) {
 
 	isClosed := common.ParseIssueFilterStateIsClosed(ctx.FormString("state"))
 
-	repoIDs, allPublic, err := buildSearchIssuesRepoIDs(ctx)
+	repoIDs, allPublic, err := common.SearchIssuesRepoIDs(ctx, common.SearchIssuesRepoIDsOptions{
+		Doer:       ctx.Doer,
+		PublicOnly: ctx.PublicOnly,
+		OwnerName:  ctx.FormString("owner"),
+		TeamName:   ctx.FormString("team"),
+	})
 	if err != nil {
 		if errors.Is(err, util.ErrNotExist) || errors.Is(err, util.ErrInvalidArgument) {
 			ctx.APIError(http.StatusBadRequest, err.Error())
@@ -204,10 +153,6 @@ func SearchIssues(ctx *context.APIContext) {
 	}
 
 	keyword := ctx.FormTrim("q")
-	if strings.IndexByte(keyword, 0) >= 0 {
-		keyword = ""
-	}
-
 	isPull := common.ParseIssueFilterTypeIsPull(ctx.FormString("type"))
 
 	var includedAnyLabels []int64
@@ -390,9 +335,6 @@ func ListIssues(ctx *context.APIContext) {
 
 	isClosed := common.ParseIssueFilterStateIsClosed(ctx.FormString("state"))
 	keyword := ctx.FormTrim("q")
-	if strings.IndexByte(keyword, 0) >= 0 {
-		keyword = ""
-	}
 
 	var labelIDs []int64
 	if splitted := strings.Split(ctx.FormString("labels"), ","); len(splitted) > 0 {
@@ -435,13 +377,7 @@ func ListIssues(ctx *context.APIContext) {
 
 	listOptions := utils.GetListOptions(ctx)
 
-	isPull := optional.None[bool]()
-	switch ctx.FormString("type") {
-	case "pulls":
-		isPull = optional.Some(true)
-	case "issues":
-		isPull = optional.Some(false)
-	}
+	isPull := common.ParseIssueFilterTypeIsPull(ctx.FormString("type"))
 
 	if isPull.Has() && !ctx.Repo.Permission.CanReadIssuesOrPulls(isPull.Value()) {
 		ctx.APIErrorNotFound()