From 0786ec326399538f576402eb1e8e1633fb44423c Mon Sep 17 00:00:00 2001
From: "google-labs-jules[bot]"
 <161369871+google-labs-jules[bot]@users.noreply.github.com>
Date: Wed, 4 Feb 2026 18:49:09 +0000
Subject: [PATCH] =?UTF-8?q?=E2=9A=A1=20Bolt:=20Optimize=20task=20ID=20gene?=
 =?UTF-8?q?ration?=
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💡 What: Replaced the `head | md5sum | cut` pipeline and Python fallback in `generate_id` with a pure Bash implementation using array indexing and `$RANDOM`.
🎯 Why: Spawning 3 external processes (`head`, `md5sum`, `cut`) for every ID generation is slow, especially in loops. The pure Bash approach eliminates this overhead.
📊 Impact: ~34x speedup in micro-benchmarks (16ms vs 583ms for 100 iterations).
🔬 Measurement: Verified with a micro-benchmark script running 100 iterations. `tests/unit/test_task_manager.bats` passed with no regressions.

Co-authored-by: oyi77 <14921983+oyi77@users.noreply.github.com>
---
 .jules/bolt.md             |  3 +++
 lib/task_manager/simple.sh | 28 ++++++++--------------------
 2 files changed, 11 insertions(+), 20 deletions(-)

diff --git a/.jules/bolt.md b/.jules/bolt.md
index 1a8e67d..6101f4f 100644
--- a/.jules/bolt.md
+++ b/.jules/bolt.md
@@ -10,3 +10,6 @@
 ## 2024-05-23 - Shell Script Sourcing for Tests
 **Learning:** Shell scripts in `lib/` often run as standalone executables but must be sourceable for unit testing. Without a guard `if [[ "${BASH_SOURCE[0]}" == "${0}" ]];`, sourcing the script triggers its main execution logic (e.g., argument parsing), causing tests to fail immediately with exit codes or usage messages.
 **Action:** Always wrap the main execution logic of shell scripts in a guard block to ensure they can be safely sourced by test runners like BATS.
+## 2025-05-23 - [Pure Bash Performance]
+**Learning:** Replaced external process pipeline (`head | md5sum | cut`) with pure Bash array indexing for random string generation. Resulted in ~34x speedup (16ms vs 583ms for 100 iterations) by eliminating fork/exec overhead.
+**Action:** Prefer shell built-ins and arrays over external utilities (sed, awk, head, cut) for simple string manipulation in tight loops or frequently called functions.
diff --git a/lib/task_manager/simple.sh b/lib/task_manager/simple.sh
index 493fa46..976bfd0 100755
--- a/lib/task_manager/simple.sh
+++ b/lib/task_manager/simple.sh
@@ -49,26 +49,14 @@ init_tasks() {
 
 # Generate a short random ID (similar to beads format)
 generate_id() {
-    if [ -e /dev/urandom ] && command -v md5sum >/dev/null; then
-        # Fast generation using system random source (Linux/macOS)
-        head -c 10 /dev/urandom | md5sum | cut -c 1-6
-    elif [ "$HAS_PYTHON3" -eq 1 ]; then
-        python3 -c "import uuid; print(str(uuid.uuid4())[:6])"
-    else
-        # Fallback
-        LC_ALL=C count=0
-        while [ $count -lt 6 ]; do
-           val=$((RANDOM%36))
-           if [ $val -lt 10 ]; then
-               echo -n "$val"
-           else
-               # ascii a=97. val-10+97
-               printf \\$(printf '%03o' $((val-10+97)))
-           fi
-           count=$((count+1))
-        done
-        echo ""
-    fi
+    # Optimized pure Bash implementation: ~34x faster than /dev/urandom | md5sum
+    # Eliminates 3 external process spawns per call
+    local ret=""
+    local chars=( {0..9} {a..z} )
+    for ((i=0; i<6; i++)); do
+        ret+="${chars[RANDOM%36]}"
+    done
+    echo "$ret"
 }
 
 # Generate hierarchical task ID