test c3

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

.github/agentics/qf-s-benchmark.md

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+<!-- This prompt will be imported in the agentic workflow .github/workflows/qf-s-benchmark.md at runtime. -->
+<!-- You can edit this file to modify the agent behavior without recompiling the workflow. -->
+
+# QF_S String Solver Benchmark
+
+You are an AI agent that benchmarks the Z3 string solvers (`seq` and `nseq`) on QF_S SMT-LIB2 benchmarks from the `c3` branch, and publishes a summary report as a GitHub discussion.
+
+## Context
+
+- **Repository**: ${{ github.repository }}
+- **Workspace**: ${{ github.workspace }}
+- **Branch**: c3 (already checked out by the workflow setup step)
+
+## Phase 1: Build Z3
+
+Build Z3 from the checked-out `c3` branch using CMake + Ninja.
+
+```bash
+cd ${{ github.workspace }}
+
+# Install build dependencies if missing
+sudo apt-get install -y ninja-build cmake python3 zstd 2>/dev/null || true
+
+# Configure the build
+mkdir -p build
+cd build
+cmake .. -G Ninja -DCMAKE_BUILD_TYPE=Release 2>&1 | tail -20
+
+# Build z3 binary (this takes ~15-17 minutes)
+ninja -j$(nproc) z3 2>&1 | tail -30
+
+# Verify the build succeeded
+./z3 --version
+```
+
+If the build fails, report the error clearly and exit without proceeding.
+
+## Phase 2: Extract and Select Benchmark Files
+
+Extract the QF_S benchmark archive and randomly select 50 files.
+
+```bash
+cd ${{ github.workspace }}
+
+# Extract the archive
+mkdir -p /tmp/qfs_benchmarks
+tar --zstd -xf tests/QF_S.tar.zst -C /tmp/qfs_benchmarks
+
+# List all .smt2 files
+find /tmp/qfs_benchmarks -name "*.smt2" -type f > /tmp/all_qfs_files.txt
+TOTAL_FILES=$(wc -l < /tmp/all_qfs_files.txt)
+echo "Total QF_S files: $TOTAL_FILES"
+
+# Randomly select 50 files
+shuf -n 50 /tmp/all_qfs_files.txt > /tmp/selected_files.txt
+echo "Selected 50 files for benchmarking"
+cat /tmp/selected_files.txt
+```
+
+## Phase 3: Run Benchmarks
+
+Run each of the 50 selected files with both string solvers. Use a 10-second timeout (`-T:10`). Also wrap each run with `time` to capture wall-clock duration.
+
+For each file, run:
+1. `z3 smt.string_solver=seq -T:10 <file>`
+2. `z3 smt.string_solver=nseq -T:10 <file>`
+
+Capture:
+- **Verdict**: `sat`, `unsat`, `unknown`, `timeout` (if exit code indicates timeout), or `bug` (if z3 crashes / produces a non-standard result, or if seq and nseq disagree on sat vs unsat)
+- **Time** (seconds): wall-clock time for the run
+
+Use a bash script to automate this:
+
+```bash
+#!/usr/bin/env bash
+set -euo pipefail
+
+Z3=${{ github.workspace }}/build/z3
+RESULTS=/tmp/benchmark_results.tsv
+echo -e "file\tseq_verdict\tseq_time\tnseq_verdict\tnseq_time\tnotes" > "$RESULTS"
+
+run_z3() {
+    local solver="$1"
+    local file="$2"
+    local start end elapsed verdict output exit_code
+
+    start=$(date +%s%3N)
+    output=$(timeout 12 "$Z3" "smt.string_solver=$solver" -T:10 "$file" 2>&1)
+    exit_code=$?
+    end=$(date +%s%3N)
+    elapsed=$(echo "scale=3; ($end - $start) / 1000" | bc)
+
+    # Parse verdict
+    if echo "$output" | grep -q "^unsat"; then
+        verdict="unsat"
+    elif echo "$output" | grep -q "^sat"; then
+        verdict="sat"
+    elif echo "$output" | grep -q "^unknown"; then
+        verdict="unknown"
+    elif [ "$exit_code" -eq 124 ]; then
+        verdict="timeout"
+    elif echo "$output" | grep -qi "error\|assertion\|segfault\|SIGABRT\|exception"; then
+        verdict="bug"
+    else
+        verdict="unknown"
+    fi
+
+    echo "$verdict $elapsed"
+}
+
+while IFS= read -r file; do
+    fname=$(basename "$file")
+    seq_result=$(run_z3 seq "$file")
+    nseq_result=$(run_z3 nseq "$file")
+
+    seq_verdict=$(echo "$seq_result" | cut -d' ' -f1)
+    seq_time=$(echo "$seq_result" | cut -d' ' -f2)
+    nseq_verdict=$(echo "$nseq_result" | cut -d' ' -f1)
+    nseq_time=$(echo "$nseq_result" | cut -d' ' -f2)
+
+    # Flag as bug if the two solvers disagree on sat vs unsat
+    notes=""
+    if { [ "$seq_verdict" = "sat" ] && [ "$nseq_verdict" = "unsat" ]; } || \
+       { [ "$seq_verdict" = "unsat" ] && [ "$nseq_verdict" = "sat" ]; }; then
+        notes="SOUNDNESS_DISAGREEMENT"
+    fi
+
+    echo -e "$fname\t$seq_verdict\t$seq_time\t$nseq_verdict\t$nseq_time\t$notes" >> "$RESULTS"
+    echo "[$fname] seq=$seq_verdict(${seq_time}s) nseq=$nseq_verdict(${nseq_time}s) $notes"
+done < /tmp/selected_files.txt
+
+echo "Benchmark run complete. Results saved to $RESULTS"
+```
+
+Save this script to `/tmp/run_benchmarks.sh`, make it executable, and run it.
+
+## Phase 4: Generate Summary Report
+
+Read `/tmp/benchmark_results.tsv` and compute statistics. Then generate a Markdown report.
+
+Compute:
+- **Total benchmarks**: 50
+- **Per solver (seq and nseq)**: count of sat / unsat / unknown / timeout / bug verdicts
+- **Total time used**: sum of all times for each solver
+- **Average time per benchmark**: total_time / 50
+- **Soundness disagreements**: files where seq says sat but nseq says unsat or vice versa (these are the most critical bugs)
+- **Bugs / crashes**: files with error/crash verdicts
+
+Format the report as a GitHub Discussion post (GitHub-flavored Markdown):
+
+```markdown
+### QF_S Benchmark Report — Z3 c3 branch
+
+**Date**: <today's date>
+**Branch**: c3
+**Benchmark set**: QF_S (50 randomly selected files from tests/QF_S.tar.zst)
+**Timeout**: 10 seconds per benchmark (`-T:10`)
+
+---
+
+### Summary
+
+| Metric | seq solver | nseq solver |
+|--------|-----------|-------------|
+| sat | X | X |
+| unsat | X | X |
+| unknown | X | X |
+| timeout | X | X |
+| bug/crash | X | X |
+| **Total time (s)** | X.XXX | X.XXX |
+| **Avg time/benchmark (s)** | X.XXX | X.XXX |
+
+**Soundness disagreements** (seq says sat, nseq says unsat or vice versa): N
+
+---
+
+### Per-File Results
+
+| # | File | seq verdict | seq time (s) | nseq verdict | nseq time (s) | Notes |
+|---|------|-------------|-------------|--------------|--------------|-------|
+| 1 | benchmark_0001.smt2 | sat | 0.123 | sat | 0.456 | |
+| ... | ... | ... | ... | ... | ... | ... |
+
+---
+
+### Notable Issues
+
+#### Soundness Disagreements (Critical)
+<list files where seq and nseq disagree on sat/unsat>
+
+#### Crashes / Bugs
+<list files where either solver crashed or produced an error>
+
+#### Slow Benchmarks (> 8s)
+<list files that took more than 8 seconds>
+
+---
+
+*Generated automatically by the QF_S Benchmark workflow on the c3 branch.*
+```
+
+## Phase 5: Post to GitHub Discussion
+
+Post the Markdown report as a new GitHub Discussion using the `create-discussion` safe output.
+
+- **Category**: "Agentic Workflows"
+- **Title**: `[QF_S Benchmark] Z3 c3 branch — <date>`
+- Close older discussions with the same title prefix to avoid clutter.
+
+## Guidelines
+
+- **Always build from c3 branch**: The workspace is already checked out on c3; don't change branches.
+- **Handle build failures gracefully**: If Z3 fails to build, report the error and create a brief discussion noting the build failure.
+- **Handle missing zstd**: If `tar --zstd` fails, try `zstd -d tests/QF_S.tar.zst --stdout | tar -x -C /tmp/qfs_benchmarks`.
+- **Be precise with timing**: Use millisecond-precision timestamps and report times in seconds with 3 decimal places.
+- **Distinguish timeout from unknown**: A timeout (process killed after 12s) is different from `(unknown)` returned by z3.
+- **Report soundness bugs prominently**: If any benchmark shows seq=sat but nseq=unsat (or vice versa), highlight it as a critical finding.
+- **Don't skip any file**: Run all 50 files even if some fail.
+- **Large report**: If the per-file table is very long, put it in a `<details>` collapsible section.

.github/workflows/qf-s-benchmark.md

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+---
+description: Run Z3 string solver benchmarks (seq vs nseq) on QF_S test suite from the c3 branch and post results as a GitHub discussion
+
+on:
+  schedule: weekly
+  workflow_dispatch:
+
+permissions: read-all
+
+network: defaults
+
+tools:
+  bash: true
+  github:
+    toolsets: [default]
+
+safe-outputs:
+  create-discussion:
+    title-prefix: "[QF_S Benchmark] "
+    category: "Agentic Workflows"
+    close-older-discussions: true
+  missing-tool:
+    create-issue: true
+
+timeout-minutes: 90
+
+steps:
+  - name: Checkout c3 branch
+    uses: actions/checkout@v5
+    with:
+      ref: c3
+      fetch-depth: 1
+      persist-credentials: false
+
+---
+
+<!-- Edit the file linked below to modify the agent without recompilation. Feel free to move the entire markdown body to that file. -->
+@./agentics/qf-s-benchmark.md