Add a timeout to createBlameReader

[mqudsi]

The timeout duration is arbitrary. The value needs to be longer than any
actual use, and should only kick in when processes aren't reaped
manually for some reason.

Closes #11716

[mqudsi]

@techknowlogick thanks for the typo correction. Nice catch.

[lafriks]

Maybe use git command timeout setting?

[mqudsi]

I'm not sure if that makes sense? Semantically they're rather different.

[lafriks]

I mean from these values: https://github.com/go-gitea/gitea/blob/master/custom/conf/app.example.ini#L910

Maybe new setting should be added for this

[techknowlogick]

@mqudsi I'd like to take credit for it, but our CI system checks for typos and provides the correct spelling. If it hadn't done that I wouldn't have noticed :)

[zeripath]

Why not just use the requesting context as the parent context - then we don't need a timeout - when the request is cancelled the command should be cancelled.

diff --git a/modules/git/blame.go b/modules/git/blame.go
index 5a9ae9a74..95ea29536 100644
--- a/modules/git/blame.go
+++ b/modules/git/blame.go
@@ -89,19 +89,19 @@ func (r *BlameReader) Close() error {
 }
 
 // CreateBlameReader creates reader for given repository, commit and file
-func CreateBlameReader(repoPath, commitID, file string) (*BlameReader, error) {
+func CreateBlameReader(ctx context.Context, repoPath, commitID, file string) (*BlameReader, error) {
        gitRepo, err := OpenRepository(repoPath)
        if err != nil {
                return nil, err
        }
        gitRepo.Close()
 
-       return createBlameReader(repoPath, GitExecutable, "blame", commitID, "--porcelain", "--", file)
+       return createBlameReader(ctx, repoPath, GitExecutable, "blame", commitID, "--porcelain", "--", f>
 }
 
-func createBlameReader(dir string, command ...string) (*BlameReader, error) {
+func createBlameReader(ctx context.Context, dir string, command ...string) (*BlameReader, error) {
        // FIXME: graceful: This should have a timeout
-       ctx, cancel := context.WithCancel(DefaultContext)
+       ctx, cancel := context.WithCancel(ctx)
        cmd := exec.CommandContext(ctx, command[0], command[1:]...)
        cmd.Dir = dir
        cmd.Stderr = os.Stderr
diff --git a/routers/repo/blame.go b/routers/repo/blame.go
index d353f3b5d..51e74006e 100644
--- a/routers/repo/blame.go
+++ b/routers/repo/blame.go
@@ -127,7 +127,7 @@ func RefBlame(ctx *context.Context) {
                return
        }
 
-       blameReader, err := git.CreateBlameReader(models.RepoPath(userName, repoName), commitID, fileNam>
+       blameReader, err := git.CreateBlameReader(ctx.Req.Context(), models.RepoPath(userName, repoName)>
        if err != nil {
                ctx.NotFound("CreateBlameReader", err)
                return