fix(shellenv): preserve newlines in exported env values (#2814)

[mikeland73]

Summary

Fixes #2814.

eval "$(devbox global shellenv)" printed bash: 1__bp_interactive_mode: ambiguous redirect at every prompt when the environment contained a multiline value (in the reporter's case a PROMPT_COMMAND built by bash-preexec / an elementary-terminal dbus hook).

Root cause

exportify (internal/devbox/envvars.go) emits each value as export KEY="…"; and escapes special characters by prefixing them with \. It also escaped \n, so a newline in a value was written as a backslash + literal newline:

export PROMPT_COMMAND="… >/dev/null 2>&1\
__bp_interactive_mode";

Inside double quotes, a backslash-newline is a line continuation — the shell removes it entirely on eval. So the newline was silently deleted and the two lines were joined:

… >/dev/null 2>&1__bp_interactive_mode

2>&1__bp_interactive_mode makes the redirect target 1__bp_interactive_mode, which bash rejects as an ambiguous redirect — exactly the reported error.

Fix

A literal newline inside double quotes is preserved as-is and needs no escaping (per the POSIX quoting rules, only $, `, ", and \ are special there). So exportify now stops escaping \n and emits the newline literally, keeping multiline values intact. A regression test pins the behavior.

The change is limited to the POSIX-shell export path; exportifyNushell already did not escape newlines and is untouched.

How was it tested?

• go test ./internal/devbox/ -run TestExportify — passes, including the new TestExportifyMultilineValue.

• go vet ./internal/devbox/ and gofmt -l — clean.

• End-to-end in real bash, reproducing the reporter's value. Before the fix the sourced value collapses to … 2>&1__bp_interactive_mode (deleted newlines → ambiguous redirect); after the fix the newlines are preserved:

  === OLD (backslash-newline, line continuation) ===
  VALUE=[echo start>/dev/null 2>&1__bp_interactive_mode]
  
  === NEW (literal newline) ===
  VALUE=[echo start
  >/dev/null 2>&1
  __bp_interactive_mode]
  

Community Contribution License

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maintainers under the terms of the
Apache 2 License.

By creating this pull request, I represent that I have the right to license the
contributions to the project maintainers under the Apache 2 License as stated in
the
Community Contribution License.

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cc @proedie (issue reporter) — thanks for the precise diagnosis, including the exact line that needed moving.

🤖 Generated with Claude Code

https://claude.ai/code/session_016JemcBvhaZqahAzACV4aQF

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Generated by Claude Code

[Copilot]

Pull request overview

This pull request fixes incorrect POSIX-shell export generation for environment variables whose values contain literal newlines (e.g., multiline PROMPT_COMMAND). It adjusts exportify so newlines are emitted literally inside double quotes (instead of being turned into backslash-newline line continuations that eval removes), and adds a regression test to lock in the behavior.

Changes:

• Stop escaping \n in internal/devbox/envvars.go POSIX-shell export generation to preserve multiline values.
• Add TestExportifyMultilineValue to ensure multiline values round-trip without producing \\\n line continuations.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
internal/devbox/envvars.go	Updates exportify escaping rules to preserve literal newlines inside double-quoted export values (fix for #2814).
internal/devbox/envvars_test.go	Adds a regression test validating multiline values remain multiline and never contain backslash-newline.

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