Bower install hangs on slow Git fetches with no timeout or cancellation option

1. Does Bower clean up after an aborted install?

When a bower install is killed (SIGINT, SIGTERM or SIGKILL), Bower does not roll back the cache. The ~/.cache/bower directory may contain a half‑cloned Git repository or a partially extracted tarball. Subsequent bower install runs can then fail or reuse corrupted data. The safest approach is to purge the cache before retrying:

bower cache clean

2. Which Git settings does Bower honor?

Bower spawns Git without any explicit timeout flags. It relies on the environment that the Bower process inherits. Two ways to influence Git’s behaviour:

• Global config – git config --global http.lowSpeedLimit 1000 and git config --global http.lowSpeedTime 30 are read by every Git invocation, including those spawned by Bower.
• Environment variables – Setting GIT_CONFIG or GIT_CONFIG_NOSYSTEM before running Bower forces Git to load a custom config file. For example:
  GIT_CONFIG=/tmp/bower-git.cfg bower install

Command‑line flags such as --timeout are not forwarded by Bower, so they have no effect.

3. External timeout pattern that avoids cache corruption

A proven pattern for CI is to wrap bower install with a timeout utility that sends a graceful SIGTERM and then cleans the cache if the command exits non‑zero. Example using the POSIX timeout command:

# Run for 30 seconds, then kill if still running
if ! timeout 30s bower install; then
  echo "Bower install timed out – cleaning cache"
  bower cache clean
  exit 1
fi

On systems without timeout, a small shell wrapper can be used:

#!/usr/bin/env bash
set -e
# Start Bower in background
bower install &
BOWER_PID=$!
# Wait with a timeout
if ! wait $BOWER_PID; then
  echo "Bower failed – cleaning cache"
  bower cache clean
  exit 1
fi

These approaches keep the cache in a clean state and provide a deterministic upper bound on install time.

4. Quick sanity check

After a timeout, run:

bower cache list

to confirm that no half‑downloaded packages remain. If any entries are marked incomplete, delete them manually or run bower cache clean again.