Xcode Build Analyzer
by @alexissan
Analyze Xcode build logs — timing, warnings, errors, slow compiles, and build history from DerivedData.
clawhub install xcode-build-analyzer📖 About This Skill
name: xcode-build-analyzer description: Analyze Xcode build logs — timing, warnings, errors, slow compiles, and build history from DerivedData. homepage: https://clawhub.ai/alexissan/xcode-build-analyzer metadata: {"clawdbot":{"emoji":"🔨","requires":{"bins":["plutil","gunzip","sqlite3"],"os":"darwin"}}}
Xcode Build Analyzer
Analyze Xcode build performance, warnings, errors, and history by reading DerivedData build logs on macOS.
Requirements
~/Library/Developer/Xcode/DerivedData/Key paths
DERIVED_DATA=~/Library/Developer/Xcode/DerivedData
Each project has a folder named
info.plist — project workspace path and last accessed dateLogs/Build/LogStoreManifest.plist — structured index of all builds (timing, status, warnings, errors)Logs/Build/*.xcactivitylog — gzip-compressed SLF build logs with per-step timing and full compiler output> Important: All queries are read-only. Never modify DerivedData contents.
List all projects in DerivedData
for dir in ~/Library/Developer/Xcode/DerivedData/*-*; do
[ -d "$dir" ] || continue
NAME="$(basename "$dir" | sed 's/-[a-z]*$//')"
WORKSPACE="$(plutil -extract WorkspacePath raw "$dir/info.plist" 2>/dev/null || echo "unknown")"
LAST_ACCESS="$(plutil -extract LastAccessedDate raw "$dir/info.plist" 2>/dev/null || echo "unknown")"
echo "$NAME | $WORKSPACE | Last accessed: $LAST_ACCESS"
done
Build history for a project
Parse the LogStoreManifest.plist for structured build data. This is the most reliable source — it contains timing, error/warning counts, and scheme info for every build without needing to decompress logs.
# Replace PROJECT_DIR with the project's DerivedData folder
To find it: ls ~/Library/Developer/Xcode/DerivedData/ | grep -i "ProjectName"
PROJECT_DIR="$(ls -d ~/Library/Developer/Xcode/DerivedData/PROJECT_NAME-* 2>/dev/null | head -1)"
MANIFEST="$PROJECT_DIR/Logs/Build/LogStoreManifest.plist"plutil -convert json -o - "$MANIFEST" 2>/dev/null | python3 -c "
import json, sys
from datetime import datetime, timezone, timedelta
data = json.load(sys.stdin)
EPOCH = datetime(2001, 1, 1, tzinfo=timezone.utc)
builds = []
for uid, log in data.get('logs', {}).items():
start = log.get('timeStartedRecording', 0)
stop = log.get('timeStoppedRecording', 0)
duration = stop - start
obs = log.get('primaryObservable', {})
dt = EPOCH + timedelta(seconds=start)
builds.append({
'date': dt.strftime('%Y-%m-%d %H:%M'),
'duration': f'{duration:.1f}s',
'scheme': log.get('schemeIdentifier-schemeName', '?'),
'status': obs.get('highLevelStatus', '?'),
'errors': obs.get('totalNumberOfErrors', 0),
'warnings': obs.get('totalNumberOfWarnings', 0),
'analyzer': obs.get('totalNumberOfAnalyzerIssues', 0),
'file': log.get('fileName', ''),
})
builds.sort(key=lambda b: b['date'], reverse=True)
for b in builds:
status = {'S': 'OK', 'W': 'Warnings', 'E': 'Error'}.get(b['status'], b['status'])
print(f\"{b['date']} {b['duration']:>8s} {status:<10s} {b['errors']}E {b['warnings']}W {b['analyzer']}A [{b['scheme']}]\")
"
Replace PROJECT_NAME with the project name (case-insensitive grep match is fine).
Status codes: S = Succeeded, W = Succeeded with Warnings, E = Failed with Errors
Latest build summary (all projects)
for dir in ~/Library/Developer/Xcode/DerivedData/*-*; do
[ -d "$dir" ] || continue
MANIFEST="$dir/Logs/Build/LogStoreManifest.plist"
[ -f "$MANIFEST" ] || continue
NAME="$(basename "$dir" | sed 's/-[a-z]*$//')" plutil -convert json -o - "$MANIFEST" 2>/dev/null | python3 -c "
import json, sys
from datetime import datetime, timezone, timedelta
data = json.load(sys.stdin)
EPOCH = datetime(2001, 1, 1, tzinfo=timezone.utc)
name = '$NAME'
latest = None
for uid, log in data.get('logs', {}).items():
start = log.get('timeStartedRecording', 0)
if latest is None or start > latest[0]:
latest = (start, log)
if latest:
start, log = latest
stop = log.get('timeStoppedRecording', 0)
obs = log.get('primaryObservable', {})
dt = EPOCH + timedelta(seconds=start)
duration = stop - start
status = {'S': 'OK', 'W': 'Warn', 'E': 'Err'}.get(obs.get('highLevelStatus', '?'), '?')
print(f\"{name:<30s} {dt.strftime('%Y-%m-%d %H:%M')} {duration:>6.1f}s {status:<5s} {obs.get('totalNumberOfErrors',0)}E {obs.get('totalNumberOfWarnings',0)}W\")
" 2>/dev/null
done
Extract warnings and errors from a build log
# Find the latest xcactivitylog for a project
PROJECT_DIR="$(ls -d ~/Library/Developer/Xcode/DerivedData/PROJECT_NAME-* 2>/dev/null | head -1)"
LATEST_LOG="$(ls -t "$PROJECT_DIR/Logs/Build/"*.xcactivitylog 2>/dev/null | head -1)"Extract warnings
gunzip -c "$LATEST_LOG" 2>/dev/null | strings | grep -E "\.swift:[0-9]+:[0-9]+: warning:" | sort -uExtract errors
gunzip -c "$LATEST_LOG" 2>/dev/null | strings | grep -E "\.swift:[0-9]+:[0-9]+: error:" | sort -u
Warning summary (grouped by type)
PROJECT_DIR="$(ls -d ~/Library/Developer/Xcode/DerivedData/PROJECT_NAME-* 2>/dev/null | head -1)"
LATEST_LOG="$(ls -t "$PROJECT_DIR/Logs/Build/"*.xcactivitylog 2>/dev/null | head -1)"gunzip -c "$LATEST_LOG" 2>/dev/null | strings \
| grep -oE "warning: .*" \
| sed 's/\[.*//; s/'"'"'[^'"'"']*'"'"'//g' \
| sort | uniq -c | sort -rn | head -20
Build step timing (find slow steps)
The xcactivitylog contains per-task TaskMetrics JSON with wall-clock duration in microseconds.
PROJECT_DIR="$(ls -d ~/Library/Developer/Xcode/DerivedData/PROJECT_NAME-* 2>/dev/null | head -1)"
LATEST_LOG="$(ls -t "$PROJECT_DIR/Logs/Build/"*.xcactivitylog 2>/dev/null | head -1)"gunzip -c "$LATEST_LOG" 2>/dev/null | strings \
| grep -o '{"wcDuration":[^}]*}' \
| python3 -c "
import json, sys
tasks = []
for line in sys.stdin:
try:
m = json.loads(line.strip())
tasks.append(m)
except: pass
tasks.sort(key=lambda t: t.get('wcDuration', 0), reverse=True)
print(f'Total tasks: {len(tasks)}')
print(f'Top 10 slowest (wall-clock microseconds):')
for i, t in enumerate(tasks[:10]):
wc = t['wcDuration']
rss = t.get('maxRSS', 0)
print(f' {i+1}. {wc/1000:.1f}ms (RSS: {rss/1024/1024:.1f}MB)')
"
DerivedData disk usage
echo "Total DerivedData size:"
du -sh ~/Library/Developer/Xcode/DerivedData/ 2>/dev/nullecho ""
echo "Per project:"
for dir in ~/Library/Developer/Xcode/DerivedData/*-*; do
[ -d "$dir" ] || continue
NAME="$(basename "$dir" | sed 's/-[a-z]*$//')"
SIZE="$(du -sh "$dir" 2>/dev/null | cut -f1)"
echo " $SIZE $NAME"
done | sort -rh
Clean DerivedData for a project
Only suggest this when the user explicitly asks. This deletes the build cache and will force a full rebuild.
# Replace PROJECT_NAME with the project name
PROJECT_DIR="$(ls -d ~/Library/Developer/Xcode/DerivedData/PROJECT_NAME-* 2>/dev/null | head -1)"
echo "Will delete: $PROJECT_DIR ($(du -sh "$PROJECT_DIR" 2>/dev/null | cut -f1))"
echo "Run: rm -rf \"$PROJECT_DIR\""
> Warning: Always confirm with the user before deleting. Suggest printing the size and path first.
Build trend (all builds for a project over time)
PROJECT_DIR="$(ls -d ~/Library/Developer/Xcode/DerivedData/PROJECT_NAME-* 2>/dev/null | head -1)"
MANIFEST="$PROJECT_DIR/Logs/Build/LogStoreManifest.plist"plutil -convert json -o - "$MANIFEST" 2>/dev/null | python3 -c "
import json, sys
from datetime import datetime, timezone, timedelta
data = json.load(sys.stdin)
EPOCH = datetime(2001, 1, 1, tzinfo=timezone.utc)
builds = []
for uid, log in data.get('logs', {}).items():
start = log.get('timeStartedRecording', 0)
stop = log.get('timeStoppedRecording', 0)
builds.append((start, stop - start))
builds.sort()
if builds:
print(f'Builds tracked: {len(builds)}')
durations = [d for _, d in builds]
print(f'Fastest: {min(durations):.1f}s')
print(f'Slowest: {max(durations):.1f}s')
print(f'Average: {sum(durations)/len(durations):.1f}s')
print(f'Median: {sorted(durations)[len(durations)//2]:.1f}s')
print()
print('Timeline:')
for start, dur in builds:
dt = EPOCH + timedelta(seconds=start)
bar = '█' * max(1, int(dur / max(durations) * 30))
print(f' {dt.strftime(\"%m/%d %H:%M\")} {dur:>6.1f}s {bar}')
"
Concurrency issues (Swift 6 readiness)
Extract Swift concurrency warnings that will become errors in Swift 6:
PROJECT_DIR="$(ls -d ~/Library/Developer/Xcode/DerivedData/PROJECT_NAME-* 2>/dev/null | head -1)"
LATEST_LOG="$(ls -t "$PROJECT_DIR/Logs/Build/"*.xcactivitylog 2>/dev/null | head -1)"gunzip -c "$LATEST_LOG" 2>/dev/null | strings \
| grep -E "(data race|Sendable|actor-isolated|crossing into|concurrency)" \
| grep "warning:" \
| sort -u
CLI builds (xcodebuild)
Important: xcodebuild CLI builds do not write to LogStoreManifest.plist or generate .xcactivitylog files unless you pass -resultBundlePath. This means the build history section above will only show Xcode IDE builds.
To detect CLI builds, check the build product timestamps and DerivedData info:
for dir in ~/Library/Developer/Xcode/DerivedData/*-*; do
[ -d "$dir" ] || continue
NAME="$(basename "$dir" | sed 's/-[a-z]*$//')"
WORKSPACE="$(plutil -extract WorkspacePath raw "$dir/info.plist" 2>/dev/null || echo "unknown")" # Detect if this is a worktree build (workspace path outside main project dir, e.g. /tmp/)
SOURCE=""
PROJ_DIR="$(dirname "$WORKSPACE")"
if [ -d "$PROJ_DIR" ] && git -C "$PROJ_DIR" rev-parse --is-inside-work-tree >/dev/null 2>&1; then
BRANCH="$(git -C "$PROJ_DIR" branch --show-current 2>/dev/null)"
IS_WORKTREE="$(git -C "$PROJ_DIR" rev-parse --is-inside-work-tree 2>/dev/null)"
MAIN_WORKTREE="$(git -C "$PROJ_DIR" worktree list 2>/dev/null | head -1 | awk '{print $1}')"
if [ "$PROJ_DIR" != "$MAIN_WORKTREE" ]; then
SOURCE=" (worktree: $BRANCH @ $PROJ_DIR)"
else
SOURCE=" (branch: $BRANCH)"
fi
fi
# Check Debug simulator product
APP="$(ls -dt "$dir/Build/Products/Debug-iphonesimulator/"*.app 2>/dev/null | head -1)"
if [ -n "$APP" ]; then
MTIME="$(stat -f '%Sm' -t '%Y-%m-%d %H:%M' "$APP" 2>/dev/null)"
VERSION=""
PLIST="$APP/Info.plist"
if [ -f "$PLIST" ]; then
SHORT="$(plutil -extract CFBundleShortVersionString raw "$PLIST" 2>/dev/null)"
BUILD="$(plutil -extract CFBundleVersion raw "$PLIST" 2>/dev/null)"
VERSION=" v${SHORT}(${BUILD})"
fi
echo "$NAME | Last build: $MTIME |$VERSION | $(basename "$APP")$SOURCE"
fi
# Check Release product
APP="$(ls -dt "$dir/Build/Products/Release-iphoneos/"*.app 2>/dev/null | head -1)"
if [ -n "$APP" ]; then
MTIME="$(stat -f '%Sm' -t '%Y-%m-%d %H:%M' "$APP" 2>/dev/null)"
echo "$NAME | Last release: $MTIME | $(basename "$APP")$SOURCE"
fi
done
> Worktrees: When building from a git worktree, Xcode creates a separate DerivedData entry (different hash) because the workspace path differs. The script above detects worktree builds by checking the git state of the workspace path and shows the branch name and worktree location.
Combined build history (IDE + CLI)
To get a complete picture of all builds (both Xcode IDE and CLI), run both the LogStoreManifest parser and the build product check. The manifest gives detailed history for IDE builds; the product timestamps give the latest CLI build per configuration.
echo "=== IDE Builds (from LogStoreManifest) ==="
for dir in ~/Library/Developer/Xcode/DerivedData/*-*; do
[ -d "$dir" ] || continue
MANIFEST="$dir/Logs/Build/LogStoreManifest.plist"
[ -f "$MANIFEST" ] || continue
NAME="$(basename "$dir" | sed 's/-[a-z]*$//')" plutil -convert json -o - "$MANIFEST" 2>/dev/null | python3 -c "
import json, sys
from datetime import datetime, timezone, timedelta
data = json.load(sys.stdin)
EPOCH = datetime(2001, 1, 1, tzinfo=timezone.utc)
name = '$NAME'
for uid, log in sorted(data.get('logs', {}).items(), key=lambda x: x[1].get('timeStartedRecording', 0), reverse=True):
start = log.get('timeStartedRecording', 0)
stop = log.get('timeStoppedRecording', 0)
obs = log.get('primaryObservable', {})
dt = EPOCH + timedelta(seconds=start)
duration = stop - start
status = {'S': 'OK', 'W': 'Warn', 'E': 'Err'}.get(obs.get('highLevelStatus', '?'), '?')
scheme = log.get('schemeIdentifier-schemeName', '?')
print(f' {name:<25s} {dt.strftime(\"%Y-%m-%d %H:%M\")} {duration:>6.1f}s {status:<5s} [{scheme}] (IDE)')
" 2>/dev/null
done
echo ""
echo "=== CLI Builds (from build products) ==="
for dir in ~/Library/Developer/Xcode/DerivedData/*-*; do
[ -d "$dir" ] || continue
NAME="$(basename "$dir" | sed 's/-[a-z]*$//')"
for APP in "$dir/Build/Products/"*/*.app; do
[ -d "$APP" ] || continue
MTIME="$(stat -f '%Sm' -t '%Y-%m-%d %H:%M' "$APP" 2>/dev/null)"
CONFIG="$(basename "$(dirname "$APP")")"
echo " $NAME $MTIME [$CONFIG] $(basename "$APP") (CLI)"
done 2>/dev/null
done
Notes
LogStoreManifest.plist is the fastest way to get build history — no decompression neededxcactivitylog files are gzip-compressed SLF (Structured Log Format); use gunzip -c + strings for quick extraction+ 978307200 to convert to Unix epoch)highLevelStatus field: S = success, W = warnings, E = errorswcDuration is in microseconds; maxRSS is in bytes📋 Tips & Best Practices
LogStoreManifest.plist is the fastest way to get build history — no decompression neededxcactivitylog files are gzip-compressed SLF (Structured Log Format); use gunzip -c + strings for quick extraction+ 978307200 to convert to Unix epoch)highLevelStatus field: S = success, W = warnings, E = errorswcDuration is in microseconds; maxRSS is in bytes