Fix CSV diff for added/deleted files (go-gitea#21189)

Fixes go-gitea#21184
Regression of go-gitea#19552

Instead of using `GetBlobByPath` I use the already existing instances.

We need more information from go-gitea#19530 if that error is still present.

routers/web/repo/compare.go

@@ -113,17 +113,17 @@ func setCsvCompareContext(ctx *context.Context) {
 		Error    string
 	}
 
-	ctx.Data["CreateCsvDiff"] = func(diffFile *gitdiff.DiffFile, baseCommit, headCommit *git.Commit) CsvDiffResult {
-		if diffFile == nil || baseCommit == nil || headCommit == nil {
+	ctx.Data["CreateCsvDiff"] = func(diffFile *gitdiff.DiffFile, baseBlob, headBlob *git.Blob) CsvDiffResult {
+		if diffFile == nil {
 			return CsvDiffResult{nil, ""}
 		}
 
 		errTooLarge := errors.New(ctx.Locale.Tr("repo.error.csv.too_large"))
 
-		csvReaderFromCommit := func(ctx *markup.RenderContext, c *git.Commit) (*csv.Reader, io.Closer, error) {
-			blob, err := c.GetBlobByPath(diffFile.Name)
-			if err != nil {
-				return nil, nil, err
+		csvReaderFromCommit := func(ctx *markup.RenderContext, blob *git.Blob) (*csv.Reader, io.Closer, error) {
+			if blob == nil {
+				// It's ok for blob to be nil (file added or deleted)
+				return nil, nil, nil
 			}
 
 			if setting.UI.CSV.MaxFileSize != 0 && setting.UI.CSV.MaxFileSize < blob.Size() {
@@ -139,28 +139,28 @@ func setCsvCompareContext(ctx *context.Context) {
 			return csvReader, reader, err
 		}
 
-		baseReader, baseBlobCloser, err := csvReaderFromCommit(&markup.RenderContext{Ctx: ctx, RelativePath: diffFile.OldName}, baseCommit)
+		baseReader, baseBlobCloser, err := csvReaderFromCommit(&markup.RenderContext{Ctx: ctx, RelativePath: diffFile.OldName}, baseBlob)
 		if baseBlobCloser != nil {
 			defer baseBlobCloser.Close()
 		}
-		if err == errTooLarge {
-			return CsvDiffResult{nil, err.Error()}
-		}
 		if err != nil {
-			log.Error("CreateCsvDiff error whilst creating baseReader from file %s in commit %s in %s: %v", diffFile.Name, baseCommit.ID.String(), ctx.Repo.Repository.Name, err)
-			return CsvDiffResult{nil, "unable to load file from base commit"}
+			if err == errTooLarge {
+				return CsvDiffResult{nil, err.Error()}
+			}
+			log.Error("error whilst creating csv.Reader from file %s in base commit %s in %s: %v", diffFile.Name, baseBlob.ID.String(), ctx.Repo.Repository.Name, err)
+			return CsvDiffResult{nil, "unable to load file"}
 		}
 
-		headReader, headBlobCloser, err := csvReaderFromCommit(&markup.RenderContext{Ctx: ctx, RelativePath: diffFile.Name}, headCommit)
+		headReader, headBlobCloser, err := csvReaderFromCommit(&markup.RenderContext{Ctx: ctx, RelativePath: diffFile.Name}, headBlob)
 		if headBlobCloser != nil {
 			defer headBlobCloser.Close()
 		}
-		if err == errTooLarge {
-			return CsvDiffResult{nil, err.Error()}
-		}
 		if err != nil {
-			log.Error("CreateCsvDiff error whilst creating headReader from file %s in commit %s in %s: %v", diffFile.Name, headCommit.ID.String(), ctx.Repo.Repository.Name, err)
-			return CsvDiffResult{nil, "unable to load file from head commit"}
+			if err == errTooLarge {
+				return CsvDiffResult{nil, err.Error()}
+			}
+			log.Error("error whilst creating csv.Reader from file %s in head commit %s in %s: %v", diffFile.Name, headBlob.ID.String(), ctx.Repo.Repository.Name, err)
+			return CsvDiffResult{nil, "unable to load file"}
 		}
 
 		sections, err := gitdiff.CreateCsvDiff(diffFile, baseReader, headReader)

templates/repo/diff/box.tmpl

@@ -153,7 +153,7 @@
 									{{if $isImage}}
 										{{template "repo/diff/image_diff" dict "file" . "root" $ "blobBase" $blobBase "blobHead" $blobHead}}
 									{{else}}
-										{{template "repo/diff/csv_diff" dict "file" . "root" $}}
+										{{template "repo/diff/csv_diff" dict "file" . "root" $ "blobBase" $blobBase "blobHead" $blobHead}}
 									{{end}}
 								</table>
 							</div>

templates/repo/diff/csv_diff.tmpl

@@ -1,6 +1,6 @@
 <tr>
 	<td>
-		{{$result := call .root.CreateCsvDiff .file .root.BaseCommit .root.HeadCommit}}
+		{{$result := call .root.CreateCsvDiff .file .blobBase .blobHead}}
 		{{if $result.Error}}
 			<div class="ui center">{{$result.Error}}</div>
 		{{else if $result.Sections}}