Example illustrating BubbleTea v2 optimizations producing invalid screen rendering with JetBrains GoLand's JediTerm.

README_for_reproducting_issue_using_JediTerm_with_BubbleTea_v2.md

jediterm-bug

Minimal reproduction of a rendering bug that affects Bubble Tea v2 applications running inside JetBrains GoLand (and all IntelliJ-based IDEs).

The Problem

GoLand's built-in terminal uses JediTerm, which does not correctly handle all ANSI escape sequences. Specifically, CBT (Cursor Backward Tab) sequences emitted by ultraviolet's differential renderer can cause invalid screen rendering when transitioning between layouts of different widths.

This program demonstrates the issue by toggling between two views recorded from a real Bubble Tea application:

• View A: A two-pane layout (44-col left + 36-col right = 80 cols total)
• View B: A single-pane layout (33-col, no right pane)

When ultraviolet diffs these two fundamentally different layouts, it produces escape sequences that JediTerm mishandles, resulting in broken rendering.

How to Reproduce

Requirements

• Go 1.25+
• GoLand (or any JetBrains IDE), or the standalone JediTerm app ForceTerm

Steps

1. Build the program:

   go build -o jediterm-bug .

2. Run it inside GoLand's Run/Debug terminal (not an external terminal):

   ./jediterm-bug

3. Press space to toggle between the two views.

The first view (two-pane layout) renders correctly. After pressing space, the second view (single-pane layout) renders incorrectly — portions of the previous layout remain visible or the new layout is misaligned.

Press q to quit.

Diagnosis

The program writes a trace.log file next to the executable that captures all terminal output including escape sequences, which can be analyzed with xxd or similar tools.

Context

This reproduction was created to support PRs that add selective capability control to ultraviolet and Bubble Tea:

Repo	PR #	Description
ultraviolet	100	DisableCaps(...Capability) method and UV_DISABLE_CAPS environment variable
Bubble Tea	1641	WithoutCaps(...uv.Capability) program option

These allow applications to disable specific terminal optimizations (e.g. CBT) for terminals that don't support them, without degrading the entire rendering pipeline.

How the Frames Were Captured

The two embedded frames (frameA and frameB) were recorded from a live gomion session using a RecordingModel wrapper that captures every View() output as JSON. The recording was then whittled down to the two-frame transition that triggers the bug.

main.go

// Program jediterm-bug reproduces a rendering bug in JediTerm (GoLand/IntelliJ)
// caused by JediTerm not supporting ultraviolet's use of differential renderer 
// when transitioning between two fundamentally different view layouts.
//
// The two frames were recorded from a real gomion session using RecordingModel.
// Frame 1: wide two-pane layout (44-col left + 36-col right)
// Frame 2: narrow single-pane layout (33-col)
//
// Press space to toggle, q to quit.
// Writes trace.log next to the executable.
package main

import (
	"fmt"
	"os"
	"path/filepath"

	tea "charm.land/bubbletea/v2"
)

func main() {
	logPath := "trace.log"
	if exe, err := os.Executable(); err == nil {
		logPath = filepath.Join(filepath.Dir(exe), "trace.log")
	}

	tee, err := newTeeWriter(os.Stdout, logPath)
	if err != nil {
		stderrf("trace log: %v\n", err)
		os.Exit(1)
	}
	defer func() {
		err := tee.Close()
		if err != nil {
			stderrf("Error: %v\n", err)
			os.Exit(1)
		}
	}()

	p := tea.NewProgram(model{}, tea.WithOutput(tee))
	if _, err := p.Run(); err != nil {
		stderrf("Error: %v\n", err)
		os.Exit(1)
	}
}

// ── Model ──

type model struct {
	viewB bool
}

func (m model) Init() tea.Cmd { return nil }

func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
	switch msg := msg.(type) {
	case tea.KeyPressMsg:
		switch msg.String() {
		case "q", "ctrl+c":
			return m, tea.Quit
		case "space":
			m.viewB = !m.viewB
		}
	}
	return m, nil
}

func (m model) View() tea.View {
	var body string
	if m.viewB {
		body = frameB
	} else {
		body = frameA
	}
	v := tea.NewView(body)
	v.AltScreen = true
	return v
}

// ── Recorded frames ──

// frameA: two-pane layout (tea.KeyPressMsg)
var frameA = "\x1b[1;38;5;46mgithub.com/mikeschinkel/gomion\x1b[m\n\x1b[38;2;0;135;255m╭──────────────────────────────────────────╮\x1b[m\x1b[38;2;188;188;188m╭──────────────────────────────────╮\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m\x1b[1m Select a Commit Target:\x1b[m                  \x1b[38;2;0;135;255m│\x1b[m\x1b[38;2;188;188;188m│\x1b[m \x1b[1;38;5;130mModule\x1b[m                           \x1b[38;2;188;188;188m│\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m   git@github.com:mikeschinkel/gomion.git \x1b[38;2;0;135;255m│\x1b[m\x1b[38;2;188;188;188m│\x1b[m \x1b[38;5;238m  github.com/mikeschinkel/go-dt\x1b[m  \x1b[38;2;188;188;188m│\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m ▶ github.com/mikeschinkel/gomion/cli     \x1b[38;2;0;135;255m│\x1b[m\x1b[38;2;188;188;188m│\x1b[m                                  \x1b[38;2;188;188;188m│\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m   github.com/mikeschinkel/gomion/gommod  \x1b[38;2;0;135;255m│\x1b[m\x1b[38;2;188;188;188m│\x1b[m \x1b[38;5;244mDependencies: 0\x1b[m                  \x1b[38;2;188;188;188m│\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m ▶ github.com/mikeschinkel/go-cfgstore    \x1b[38;2;0;135;255m│\x1b[m\x1b[38;2;188;188;188m│\x1b[m                                  \x1b[38;2;188;188;188m│\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m ▶ github.com/mikeschinkel/go-logutil     \x1b[38;2;0;135;255m│\x1b[m\x1b[38;2;188;188;188m│\x1b[m \x1b[1;38;5;130mStatus\x1b[m                           \x1b[38;2;188;188;188m│\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m ▶ github.com/mikeschinkel/go-cliutil     \x1b[38;2;0;135;255m│\x1b[m\x1b[38;2;188;188;188m│\x1b[m   \x1b[1;38;5;166m● Uncommitted changes\x1b[m          \x1b[38;2;188;188;188m│\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m ▶ github.com/mikeschinkel/go-dt/dtx      \x1b[38;2;0;135;255m│\x1b[m\x1b[38;2;188;188;188m│\x1b[m                                  \x1b[38;2;188;188;188m│\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m\x1b[1;38;5;230;48;5;62m ▶ github.com/mikeschinkel/go-dt \x1b[m\x1b[48;5;62m         \x1b[m\x1b[38;2;0;135;255m│\x1b[m\x1b[38;2;188;188;188m│\x1b[m \x1b[1;38;5;130mCommit Group\x1b[m                     \x1b[38;2;188;188;188m│\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m                                          \x1b[38;2;0;135;255m│\x1b[m\x1b[38;2;188;188;188m│\x1b[m   \x1b[38;5;166m✗ go-dt/\x1b[m                       \x1b[38;2;188;188;188m│\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m                                          \x1b[38;2;0;135;255m│\x1b[m\x1b[38;2;188;188;188m│\x1b[m   \x1b[38;5;28m✓ go-dt/test/\x1b[m                  \x1b[38;2;188;188;188m│\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m                                          \x1b[38;2;0;135;255m│\x1b[m\x1b[38;2;188;188;188m│\x1b[m   \x1b[38;5;28m✓ go-dt/examples/basic_usage/\x1b[m  \x1b[38;2;188;188;188m│\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m                                          \x1b[38;2;0;135;255m│\x1b[m\x1b[38;2;188;188;188m│\x1b[m                                  \x1b[38;2;188;188;188m│\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m                                          \x1b[38;2;0;135;255m│\x1b[m\x1b[38;2;188;188;188m│\x1b[m \x1b[1;38;5;130mLatest Tag\x1b[m                       \x1b[38;2;188;188;188m│\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m                                          \x1b[38;2;0;135;255m│\x1b[m\x1b[38;2;188;188;188m│\x1b[m   \x1b[38;5;28mv0.6.0\x1b[m                         \x1b[38;2;188;188;188m│\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m                                          \x1b[38;2;0;135;255m│\x1b[m\x1b[38;2;188;188;188m│\x1b[m \x1b[38;5;244m  Up to date\x1b[m                     \x1b[38;2;188;188;188m│\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m                                          \x1b[38;2;0;135;255m│\x1b[m\x1b[38;2;188;188;188m│\x1b[m                                  \x1b[38;2;188;188;188m│\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m                                          \x1b[38;2;0;135;255m│\x1b[m\x1b[38;2;188;188;188m│\x1b[m \x1b[1;38;5;130mScan Directories\x1b[m                 \x1b[38;2;188;188;188m│\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m                                          \x1b[38;2;0;135;255m│\x1b[m\x1b[38;2;188;188;188m│\x1b[m \x1b[38;5;244m  ~/Projects/go-pkgs\x1b[m             \x1b[38;2;188;188;188m│\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m                                          \x1b[38;2;0;135;255m│\x1b[m\x1b[38;2;188;188;188m│\x1b[m \x1b[38;5;244m  ~/Projects/xmlui\x1b[m               \x1b[38;2;188;188;188m│\x1b[m\n\x1b[38;2;0;135;255m╰──────────────────────────────────────────╯\x1b[m\x1b[38;2;188;188;188m╰──────────────────────────────────╯\x1b[m\n \x1b[1;38;5;30m[?]\x1b[m \x1b[38;5;238mMenu\x1b[m  \x1b[1;38;5;30m[n]\x1b[m \x1b[38;5;238mGuide\x1b[m  \x1b[1;38;5;30m[enter]\x1b[m \x1b[38;5;238mSelect\x1b[m  \x1b[1;38;5;30m[q]\x1b[m \x1b[38;5;238mQuit\x1b[m              \x1b[1;38;5;166mUncommitted\x1b[m\x1b[38;5;250m | \x1b[m\x1b[38;5;244mv0.6.0\x1b[m"

// frameB: single-pane layout (gomtui.DrillDownMsg)
var frameB = "\x1b[38;5;34mgomion\x1b[m\x1b[38;5;51m > \x1b[m\x1b[1;38;5;46mgithub.com/mikeschinkel/go-dt\x1b[m\n\x1b[38;2;0;135;255m╭───────────────────────────────╮\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m \x1b[1;38;5;130mFiles to Commit:\x1b[m              \x1b[38;2;0;135;255m│\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m └─▼ \x1b[7;38;2;128;128;128mgo-dt\x1b[m [\x1b[38;2;128;128;128mo\x1b[m]                 \x1b[38;2;0;135;255m│\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m   └─ \x1b[38;2;128;128;128mpath_segments_ext.go\x1b[m [\x1b[38;2;128;128;128mo\x1b[m] \x1b[38;2;0;135;255m│\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m                               \x1b[38;2;0;135;255m│\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m                               \x1b[38;2;0;135;255m│\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m                               \x1b[38;2;0;135;255m│\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m                               \x1b[38;2;0;135;255m│\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m                               \x1b[38;2;0;135;255m│\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m                               \x1b[38;2;0;135;255m│\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m                               \x1b[38;2;0;135;255m│\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m                               \x1b[38;2;0;135;255m│\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m                               \x1b[38;2;0;135;255m│\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m                               \x1b[38;2;0;135;255m│\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m                               \x1b[38;2;0;135;255m│\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m                               \x1b[38;2;0;135;255m│\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m                               \x1b[38;2;0;135;255m│\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m                               \x1b[38;2;0;135;255m│\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m                               \x1b[38;2;0;135;255m│\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m                               \x1b[38;2;0;135;255m│\x1b[m\n\x1b[38;2;0;135;255m│\x1b[m                               \x1b[38;2;0;135;255m│\x1b[m\n\x1b[38;2;0;135;255m╰───────────────────────────────╯\x1b[m\n \x1b[1;38;5;30m[?]\x1b[m \x1b[38;5;238mMenu\x1b[m  \x1b[1;38;5;30m[n]\x1b[m \x1b[38;5;238mGuide\x1b[m  \x1b[1;38;5;30m[tab]\x1b[m \x1b[38;5;238mSwitch pane\x1b[m  \x1b[1;38;5;30m[esc]\x1b[m \x1b[38;5;238mBack\x1b[m  \x1b[1;38;5;30m[enter]\x1b[m \x1b[38;5;238mCommits\x1b[m            "

// ── TeeWriter ──

type teeWriter struct {
	file *os.File
	log  *os.File
}

func newTeeWriter(output *os.File, logPath string) (*teeWriter, error) {
	logFile, err := os.Create(logPath)
	if err != nil {
		return nil, err
	}
	return &teeWriter{file: output, log: logFile}, nil
}

func (w *teeWriter) Write(p []byte) (n int, err error) {
	n, err = w.file.Write(p)
	if err == nil {
		_, err = w.log.Write(p[:n])
	}
	return n, err
}

func (w *teeWriter) Read(p []byte) (int, error) { return w.file.Read(p) }
func (w *teeWriter) Fd() uintptr                { return w.file.Fd() }
func (w *teeWriter) Close() error               { return w.log.Close() }

func stderrf(format string, args ...any) {
	_, _ = fmt.Fprintf(os.Stderr, format, args...)
}