fix(v2): set LANG for pbpaste/pbcopy to prevent clipboard mojibake on macOS

[veeceey]

Fixes #4132

When a Wails app runs as a standalone macOS app (not launched from a terminal), the LANG environment variable is unset. pbpaste then defaults to an ASCII-compatible encoding, which turns non-ASCII clipboard content into garbage.

The fix ensures LANG=en_US.UTF-8 is set in the command's environment before invoking pbpaste/pbcopy, but only when LANG isn't already present — so it won't override anything the user has explicitly set.

Quick terminal demo showing the difference:

$ echo "你好世界 こんにちは" | pbcopy

$ LANG= pbpaste
Test: ???? ?????

$ LANG=en_US.UTF-8 pbpaste
Test: 你好世界 こんにちは

Summary by CodeRabbit

• Bug Fixes
  • Improved macOS clipboard handling so copied and pasted text preserve UTF-8 characters and no longer appear garbled in packaged apps.
• Documentation
  • Added a changelog entry noting the macOS clipboard mojibake fix.

[veeceey]

Manual test results (macOS 15, M4)

Verified the fix works by testing pbpaste behavior with and without LANG:

$ echo "你好世界 こんにちは" | pbcopy

# Without LANG (simulates standalone app launch):
$ LANG= pbpaste
Test: ???? ?????

# With LANG=en_US.UTF-8 (what this PR does):
$ LANG=en_US.UTF-8 pbpaste
Test: 你好世界 こんにちは

Also confirmed that go build ./v2/internal/frontend/desktop/darwin/ compiles cleanly.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

Configuration used: defaults

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between b34587e and cf15fd6.

📒 Files selected for processing (1)

• website/src/pages/changelog.mdx

---

📝 Walkthrough

Walkthrough

Adds an ensureUTF8Env helper and applies it to the pbpaste and pbcopy command environments so macOS clipboard reads/writes run with LANG set to en_US.UTF-8 when LANG is unset.

Changes

Cohort / File(s)	Summary
Clipboard UTF-8 Environment Fix v2/internal/frontend/desktop/darwin/clipboard.go	Adds ensureUTF8Env() helper, imports os, and sets Cmd.Env = ensureUTF8Env(os.Environ()) for both ClipboardGetText (pbpaste) and ClipboardSetText (pbcopy). Adds explanatory comment about packaged macOS apps and LANG.
Changelog entry website/src/pages/changelog.mdx	Adds a changelog line under "Fixed" describing the macOS clipboard mojibake fix and referencing the PR.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

Possibly related issues

• Incorrect Clipboard Text Encoding when LANG Environment Variable is Empty on macOS #4132: Implements setting LANG=en_US.UTF-8 for pbpaste/pbcopy to prevent mojibake when LANG is empty, which matches this change's objective.

Suggested reviewers

• makew0rld

Poem

🐇 I nibble at bugs beneath the moonlight,
LANG set to UTF-8, clipboard feels right.
Pastes no longer garble, copies hum bright,
A tiny rabbit hop fixed text’s flight. 🥕

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately and specifically describes the main change: setting LANG for pbpaste/pbcopy to fix clipboard mojibake on macOS.
Description check	✅ Passed	The description covers the issue (Fixes #4132), problem context, solution approach, and includes a practical demo. The changelog was updated as required, and most template sections are addressed.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

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[coderabbitai]

Actionable comments posted: 1

🧹 Nitpick comments (1)

v2/internal/frontend/desktop/darwin/clipboard.go (1)

14-22: Consider os.LookupEnv for a cleaner, more idiomatic implementation.

os.LookupEnv explicitly distinguishes "not set" from "set to empty" without manual string slicing, and is the standard Go idiom for this pattern:

♻️ Proposed refactor

 func ensureUTF8Env() []string {
 	env := os.Environ()
-	for _, e := range env {
-		if len(e) > 5 && e[:5] == "LANG=" {
-			return env
-		}
+	if _, ok := os.LookupEnv("LANG"); !ok {
+		env = append(env, "LANG=en_US.UTF-8")
 	}
-	return append(env, "LANG=en_US.UTF-8")
+	return env
 }

This also correctly handles the case where LANG is set but empty (keeping the existing empty value rather than creating a duplicate entry), which the current loop misses due to the > 5 boundary.

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@v2/internal/frontend/desktop/darwin/clipboard.go` around lines 14 - 22,
Replace the manual loop in ensureUTF8Env with os.LookupEnv: use
os.LookupEnv("LANG") to detect whether LANG is present (allowing an existing
empty value to be preserved) and, if not present, append "LANG=en_US.UTF-8" to
os.Environ(); ensure you return the original env unchanged when LANG is set
(including empty string) to avoid duplicating entries and to follow Go idioms.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@v2/internal/frontend/desktop/darwin/clipboard.go`:
- Line 17: The guard that checks environment entries uses len(e) > 5 && e[:5] ==
"LANG=" which misses the exact "LANG=" entry; update the check in the loop over
environment entries (the variable e) to use a correct boundary such as len(e) >=
5 && e[:5] == "LANG=" or, better, strings.HasPrefix(e, "LANG=") so entries equal
to "LANG=" are treated as matches and the function will early-return instead of
appending a second LANG variable.

---

Nitpick comments:
In `@v2/internal/frontend/desktop/darwin/clipboard.go`:
- Around line 14-22: Replace the manual loop in ensureUTF8Env with os.LookupEnv:
use os.LookupEnv("LANG") to detect whether LANG is present (allowing an existing
empty value to be preserved) and, if not present, append "LANG=en_US.UTF-8" to
os.Environ(); ensure you return the original env unchanged when LANG is set
(including empty string) to avoid duplicating entries and to follow Go idioms.

[coderabbitai]

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Duplicate comments:
In `@v2/internal/frontend/desktop/darwin/clipboard.go`:
- Around line 14-20: The function ensureUTF8Env correctly uses
os.LookupEnv("LANG") to detect presence (including an empty LANG=) and only
appends "LANG=en_US.UTF-8" when absent, so no code change is required; keep the
current implementation (ensureUTF8Env) as-is and approve the change.

[leaanthony]

Thanks 🙏 Please could you add an entry to the changelog located at website/src/pages/changelog.mdx?

[veeceey]

Added changelog entry. Thanks for the review!