Shell hangs on init when an alias contains a literal ESC byte (\x1b)

[nflx]

Description

Warp hangs during shell initialization if any alias in ~/.bashrc (or other rc files) contains a literal ESC byte (\x1b, visible as ^[ in cat -A).

Root Cause

Warp collects all shell aliases at bootstrap time (via alias) and encodes them into a DCS/OSC terminal escape sequence to send metadata to the UI (warp_bootstrapped). A raw \x1b byte inside that sequence terminates it prematurely, corrupting the entire bootstrap — causing it to loop and echo interactively rather than initialize silently.

Steps to Reproduce

1. Add an alias to ~/.bashrc that contains a literal ESC byte, e.g. via copy-paste from a terminal. Example (the ^[ below is a real ESC byte, not the two characters \ and [):

   alias gls="git log --pretty=short|egrep -v '^(^[\[[0-9;]*m|^[\[m )+$'"

2. Open a new Warp tab.
3. Warp hangs — the bootstrap script is echoed at the interactive prompt repeatedly instead of initializing silently.

Expected Behavior

Warp should either:

• Handle raw ESC bytes in alias output gracefully (strip or hex-encode them before embedding in escape sequences), or
• Detect the problematic alias and emit a warning pointing to the culprit

Actual Behavior

Warp hangs indefinitely. The bootstrap content is echoed as interactive shell input with > continuation prompts, repeating in a loop. There is no error message or indication of the cause.

Workaround

Replace literal ESC bytes in aliases with \e (supported by GNU egrep/grep):

alias gls="git log --pretty=short|egrep -v '^(\\e\\[[0-9;]*m|\\e\\[m )+\$'"

Notes

• This is very hard to diagnose because the alias definition looks correct when viewed in a text editor (the ESC byte is invisible), and the failure mode gives no useful signal about the root cause.
• Diagnosing required binary-searching ~/.bashrc with temporary return statements, then using cat -A to reveal the hidden byte on the identified line.
• The issue is not listed in the known issues / incompatible tools documentation.

Environment

• OS: Ubuntu Linux 6.8.0
• Shell: bash