🤔 Context Support (v0.4.0) - Do we need it? Your feedback wanted!

[kolkov]

Hi everyone! 👋

We're planning v0.4.0 and considering adding Context Support for cancellable operations. Before implementing, we'd love to hear your thoughts on whether this feature would be useful for your use cases.

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🎯 What is Context Support?

Context support would allow you to cancel long-running operations (reading/writing large MAT-files) at any time.

Current behavior (v0.3.0):

// Once started, operation MUST complete
matFile, err := matlab.Open(bigFile)
// No way to cancel or timeout ❌

Proposed behavior (v0.4.0):

// Cancellable with timeout
ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
defer cancel()

matFile, err := matlab.OpenWithContext(ctx, bigFile)
// Automatically stops after 30 seconds ✅
// OR if user clicks "Cancel" button ✅

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💡 Use Cases

1. Web API with automatic timeout

func handleUpload(w http.ResponseWriter, r *http.Request) {
    // Timeout after 30 seconds
    ctx, cancel := context.WithTimeout(r.Context(), 30*time.Second)
    defer cancel()

    matFile, err := matlab.OpenWithContext(ctx, r.Body)
    if errors.Is(err, context.DeadlineExceeded) {
        http.Error(w, "Upload timeout", 408)
        return
    }
}

Benefit: Server stops processing if client disconnects (saves CPU/memory).

2. CLI tool with Ctrl+C support

func main() {
    // Cancel on SIGINT (Ctrl+C)
    ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt)
    defer stop()

    file, _ := os.Open("huge.mat")

    fmt.Println("Processing... (Press Ctrl+C to cancel)")
    matFile, err := matlab.OpenWithContext(ctx, file)

    if errors.Is(err, context.Canceled) {
        fmt.Println("Cancelled by user")
        return
    }
}

Benefit: User can interrupt long operations with Ctrl+C.

3. Desktop app with cancel button

func loadFile(filename string) {
    ctx, cancel := context.WithCancel(context.Background())

    // Progress dialog with working Cancel button
    dialog := showProgressDialog("Loading...", func() {
        cancel()  // User clicked Cancel
    })
    defer dialog.Close()

    file, _ := os.Open(filename)
    matFile, err := matlab.OpenWithContext(ctx, file)

    if errors.Is(err, context.Canceled) {
        showMessage("Cancelled by user")
        return
    }
}

Benefit: Cancel button actually works, responsive UI.

4. Protection from corrupted files

// Timeout prevents hanging on corrupted files
ctx, cancel := context.WithTimeout(context.Background(), 5*time.Minute)
defer cancel()

matFile, err := matlab.OpenWithContext(ctx, suspiciousFile)
if errors.Is(err, context.DeadlineExceeded) {
    log.Error("File processing timeout - probably corrupted")
    return
}

Benefit: Protection from infinite hangs.

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🔧 Technical Details

Proposed API:

// New context-aware functions
func OpenWithContext(ctx context.Context, r io.Reader) (*MatFile, error)
func (w *MatFileWriter) WriteVariableWithContext(ctx context.Context, v *Variable) error

// Existing functions still work (backward compatible)
func Open(r io.Reader) (*MatFile, error)
func (w *MatFileWriter) WriteVariable(v *Variable) error

Performance:

• Context checked every 64KB (not every byte)
• Overhead: ~1% for large files
• No overhead for small files (<1MB)

Backward compatibility:

• ✅ 100% backward compatible
• Existing code continues to work unchanged
• New functions are opt-in

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❓ Questions for the Community

We need your input to decide if this feature is worth implementing:

1. Do you work with large MAT-files?

• Yes, regularly (>100MB files)
• Sometimes (10-100MB files)
• Rarely (<10MB files)

2. What's your use case?

• Web API / HTTP server
• CLI tool / batch processing
• Desktop application with UI
• Embedded system / IoT
• Data science / Jupyter notebooks
• Other (please describe)

3. Have you encountered these problems?

• Operations that take too long to complete
• Need to cancel ongoing operations
• Need timeout protection
• Unresponsive UI during file processing
• Server resources wasted on disconnected clients
• None of the above

4. How important is this feature for you?

• Critical - We need this for production
• High - Would be very useful
• Medium - Nice to have
• Low - Not needed for our use case

5. Would you use this feature?

• Yes, immediately
• Yes, in the future
• Maybe
• No, our files are small enough

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🎯 Priority Decision

Based on ROADMAP.md, this feature is currently marked as 🟢 Low Priority (planned for v0.4.0 or later).

We'll implement it if:

• Multiple users report need for cancellation/timeout
• Production use cases require it
• Community votes for it

We'll defer it if:

• No strong demand from users
• Current API is sufficient for most use cases
• Other features are more important

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💬 Your Feedback

Please share your thoughts:

1. Do you need this feature? Why or why not?
2. What file sizes do you typically work with?
3. What's your use case? (web, CLI, desktop, etc.)
4. Any other context-related features you'd like?

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📚 More Information

• Full specification: TASK-013: Context Support (542 lines)
• Roadmap: v0.4.0 Planning
• Implementation time: 1-2 days (if we decide to do it)

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🗳️ Vote with Reactions

Use reactions to vote quickly:

• 👍 Yes, we need this feature
• 👎 No, not needed
• ❤️ Critical for our use case
• 🎉 Nice to have
• 🤔 Unsure, need more info

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Thank you for your feedback! Your input helps us prioritize features that matter most to the community.

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Posted by maintainers | Category: Ideas | v0.4.0 Planning