chore: enable forcetypeassert linter, fix issues (#38804)

Enable [`forcetypeassert`](https://github.com/gostaticanalysis/forcetypeassert)
linter to prevent unchecked type assertions. ~650 issues fixed, most
fixes were clean, some use `setting.PanicInDevOrTesting`.

The only behaviour changes are where code would previously send a 500 error
or panic, a 4xx error is now emitted.

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

modules/indexer/code/bleve/bleve.go

@@ -21,6 +21,7 @@ import (
 	"gitea.dev/modules/indexer/code/internal"
 	indexer_internal "gitea.dev/modules/indexer/internal"
 	inner_bleve "gitea.dev/modules/indexer/internal/bleve"
+	"gitea.dev/modules/json"
 	"gitea.dev/modules/setting"
 	"gitea.dev/modules/timeutil"
 	"gitea.dev/modules/typesniffer"
@@ -330,6 +331,17 @@ func (b *Indexer) Search(ctx context.Context, opts *internal.SearchOptions) (int
 
 	searchResults := make([]*internal.SearchResult, len(result.Hits))
 	for i, hit := range result.Hits {
+		content, okContent := hit.Fields["Content"].(string)
+		language, okLanguage := hit.Fields["Language"].(string)
+		commitID, okCommitID := hit.Fields["CommitID"].(string)
+		updatedAt, okUpdatedAt := hit.Fields["UpdatedAt"].(string)
+		repoID, okRepoID := hit.Fields["RepoID"].(float64)
+		if !okContent || !okLanguage || !okCommitID || !okUpdatedAt || !okRepoID {
+			hitFieldsJson, _ := json.Marshal(hit.Fields)
+			setting.PanicInDevOrTesting("unexpected field types in search hit %q: %s", hit.ID, string(hitFieldsJson))
+			return 0, nil, nil, fmt.Errorf("unexpected field types in search hit %q", hit.ID)
+		}
+
 		startIndex, endIndex := -1, -1
 		for _, locations := range hit.Locations["Content"] {
 			location := locations[0]
@@ -343,21 +355,20 @@ func (b *Indexer) Search(ctx context.Context, opts *internal.SearchOptions) (int
 			}
 		}
 		if len(hit.Locations["Filename"]) > 0 {
-			startIndex, endIndex = internal.FilenameMatchIndexPos(hit.Fields["Content"].(string))
+			startIndex, endIndex = internal.FilenameMatchIndexPos(content)
 		}
 
-		language := hit.Fields["Language"].(string)
 		var updatedUnix timeutil.TimeStamp
-		if t, err := time.Parse(time.RFC3339, hit.Fields["UpdatedAt"].(string)); err == nil {
+		if t, err := time.Parse(time.RFC3339, updatedAt); err == nil {
 			updatedUnix = timeutil.TimeStamp(t.Unix())
 		}
 		searchResults[i] = &internal.SearchResult{
-			RepoID:      int64(hit.Fields["RepoID"].(float64)),
+			RepoID:      int64(repoID),
 			StartIndex:  startIndex,
 			EndIndex:    endIndex,
 			Filename:    internal.FilenameOfIndexerID(hit.ID),
-			Content:     hit.Fields["Content"].(string),
-			CommitID:    hit.Fields["CommitID"].(string),
+			Content:     content,
+			CommitID:    commitID,
 			UpdatedUnix: updatedUnix,
 			Language:    language,
 			Color:       enry.GetColor(language),

modules/indexer/code/elasticsearch/elasticsearch.go

@@ -261,12 +261,21 @@ func convertResult(searchResult *es.SearchResponse, kw string, pageSize int) (in
 			return 0, nil, nil, err
 		}
 
+		content, okContent := res["content"].(string)
+		language, okLanguage := res["language"].(string)
+		commitID, okCommitID := res["commit_id"].(string)
+		updatedAt, okUpdatedAt := res["updated_at"].(float64)
+		if !okContent || !okLanguage || !okCommitID || !okUpdatedAt {
+			setting.PanicInDevOrTesting("unexpected field types in search hit %q: %s", hit.ID, string(hit.Source))
+			return 0, nil, nil, fmt.Errorf("unexpected field types in search hit %q", hit.ID)
+		}
+
 		// FIXME: There is no way to get the position the keyword on the content currently on the same request.
 		// So we get it from content, this may made the query slower. See
 		// https://discuss.elastic.co/t/fetching-position-of-keyword-in-matched-document/94291
 		var startIndex, endIndex int
 		if c, ok := hit.Highlight["filename"]; ok && len(c) > 0 {
-			startIndex, endIndex = internal.FilenameMatchIndexPos(res["content"].(string))
+			startIndex, endIndex = internal.FilenameMatchIndexPos(content)
 		} else if c, ok := hit.Highlight["content"]; ok && len(c) > 0 {
 			// FIXME: Since the highlighting content will include <em> and </em> for the keywords,
 			// now we should find the positions. But how to avoid html content which contains the
@@ -279,14 +288,12 @@ func convertResult(searchResult *es.SearchResponse, kw string, pageSize int) (in
 			panic(fmt.Sprintf("2===%#v", hit.Highlight))
 		}
 
-		language := res["language"].(string)
-
 		hits = append(hits, &internal.SearchResult{
 			RepoID:      repoID,
 			Filename:    fileName,
-			CommitID:    res["commit_id"].(string),
-			Content:     res["content"].(string),
-			UpdatedUnix: timeutil.TimeStamp(res["updated_at"].(float64)),
+			CommitID:    commitID,
+			Content:     content,
+			UpdatedUnix: timeutil.TimeStamp(updatedAt),
 			Language:    language,
 			StartIndex:  startIndex,
 			EndIndex:    endIndex,