feat(bundler): allow customizing DMG detach attempts via env vars

[tranhoangtu-it]

close #14686

On CI with large DMG files, hdiutil detach frequently times out with EBUSY (exit code 16). The retry loop in hdiutil_detach_retry had both the attempt count and the sleep base delay hardcoded.

Changes

Two env vars with backward-compatible defaults:

• TAURI_DMG_DETACH_ATTEMPTS — max retries (default: 3)
• TAURI_DMG_DETACH_DELAY — base delay in seconds for exponential backoff (default: 1)

Usage

TAURI_DMG_DETACH_ATTEMPTS=10 TAURI_DMG_DETACH_DELAY=2 cargo tauri build

No behavior change when env vars are unset.

[Copilot]

Pull request overview

Adds configurability to the macOS DMG bundling script’s hdiutil detach retry behavior to better handle CI timeouts/EBUSY scenarios, while preserving current defaults when the new env vars are unset.

Changes:

• Reads TAURI_DMG_DETACH_ATTEMPTS to control the max detach attempts (default 3).
• Reads TAURI_DMG_DETACH_DELAY to control the exponential-backoff base delay (default 1 second).
• Uses the configured delay in the sleep backoff calculation.

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[Copilot]

MAXIMUM_UNMOUNTING_ATTEMPTS and DMG_DETACH_DELAY come directly from env vars but are later used in (( ... )) / $(( ... )). With set -e, non-integer/empty/negative values (e.g. TAURI_DMG_DETACH_ATTEMPTS=abc or TAURI_DMG_DETACH_DELAY=0.5) can trigger an arithmetic error and abort the script (or result in a 0s sleep and tight retry loop). Consider validating these as positive integers up front and either falling back to defaults or exiting with a clear error message.

Suggested change

	DMG_DETACH_DELAY="${TAURI_DMG_DETACH_DELAY:-1}"
	DMG_DETACH_DELAY="${TAURI_DMG_DETACH_DELAY:-1}"
	# Validate numeric configuration derived from environment
	if ! [[ "$MAXIMUM_UNMOUNTING_ATTEMPTS" =~ ^[1-9][0-9]*$ ]]; then
	echo "Warning: TAURI_DMG_DETACH_ATTEMPTS must be a positive integer; using default 3." >&2
	MAXIMUM_UNMOUNTING_ATTEMPTS=3
	fi
	if ! [[ "$DMG_DETACH_DELAY" =~ ^[1-9][0-9]*$ ]]; then
	echo "Warning: TAURI_DMG_DETACH_DELAY must be a positive integer; using default 1." >&2
	DMG_DETACH_DELAY=1
	fi

[Copilot]

The loop increments unmounting_attempts before attempting hdiutil detach, and exits when unmounting_attempts == MAXIMUM_UNMOUNTING_ATTEMPTS, so this variable currently represents the total number of detach attempts, not the number of retries after the first attempt. Since TAURI_DMG_DETACH_ATTEMPTS is a user-facing knob, it would help to either (a) adjust the logic so the env var truly means “retries”, or (b) add an inline comment clarifying it is “total attempts (including the first)”, to prevent off-by-one surprises.

Suggested change

	SKIP_JENKINS=0
	SKIP_JENKINS=0
	# Total number of detach attempts (including the first), controlled via TAURI_DMG_DETACH_ATTEMPTS