From 8944c3fd59ad3c3264542bf6b99e4da90b0c6151 Mon Sep 17 00:00:00 2001
From: Victor M Varela <vmvarela@gmail.com>
Date: Sat, 12 Sep 2026 10:15:42 +0200
Subject: [PATCH 1/2] fix: panic on empty no-op query (Issue #228)

---
 src/format.zig |  6 +++---
 src/main.zig   | 18 +++++++++++++-----
 2 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/src/format.zig b/src/format.zig
index b11caeb..eb3202c 100644
--- a/src/format.zig
+++ b/src/format.zig
@@ -143,11 +143,11 @@ pub const OutputWriter = struct {
     /// XML:     writes the XML declaration and opening root element
     /// CSV/TSV: writes an optional header row (when opts.header = true)
     ///
-    /// Pre:  stmt is a valid prepared statement; col_count = sqlite3_column_count(stmt)
+    /// Pre:  stmt is a valid prepared statement or null when query compiled to no statement (e.g. ";"); col_count = 0 in that case
     pub fn begin(
         self: *OutputWriter,
         allocator: std.mem.Allocator,
-        stmt: *c.sqlite3_stmt,
+        stmt: ?*c.sqlite3_stmt,
         col_count: c_int,
         writer: *std.Io.Writer,
     ) !void {
@@ -166,7 +166,7 @@ pub const OutputWriter = struct {
             },
             .csv, .tsv => {
                 if (self.opts.header and col_count > 0)
-                    try csvPrintHeaderRow(stmt, col_count, writer, self.csvDelimiter());
+                    try csvPrintHeaderRow(stmt.?, col_count, writer, self.csvDelimiter());
             },
             .markdown => unreachable, // handled before OutputWriter in execQuery
         }
diff --git a/src/main.zig b/src/main.zig
index 03265c7..17193fb 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -103,13 +103,15 @@ fn writeWithChecksum(
 fn writeStreaming(
     out_writer: *format.OutputWriter,
     allocator: std.mem.Allocator,
-    stmt: *c.sqlite3_stmt,
+    stmt: ?*c.sqlite3_stmt,
     col_count: c_int,
     writer: *std.Io.Writer,
 ) !void {
     try out_writer.begin(allocator, stmt, col_count, writer);
-    while (c.sqlite3_step(stmt) == c.SQLITE_ROW) {
-        try out_writer.writeRow(stmt, writer);
+    if (stmt) |s| {
+        while (c.sqlite3_step(s) == c.SQLITE_ROW) {
+            try out_writer.writeRow(s, writer);
+        }
     }
     try out_writer.end(writer);
 }
@@ -258,7 +260,13 @@ pub fn execQuery(
         return error.PrepareQueryFailed;
     defer _ = c.sqlite3_finalize(stmt);
 
-    const col_count = c.sqlite3_column_count(stmt);
+    // ponytail: prepare ";" succeeds with NULL stmt — empty result, no panic
+    if (stmt == null) {
+        if (use_table) return;
+        if (output_format == .markdown) return;
+    }
+
+    const col_count: c_int = if (stmt) |s| c.sqlite3_column_count(s) else 0;
 
     // Table mode: buffer all rows and print a formatted table
     if (use_table) {
@@ -282,7 +290,7 @@ pub fn execQuery(
     });
     defer out_writer.deinit(allocator);
 
-    try writeWithChecksum(allocator, writer, stderr_writer, checksum, .{ &out_writer, allocator, stmt.?, col_count }, writeStreaming);
+    try writeWithChecksum(allocator, writer, stderr_writer, checksum, .{ &out_writer, allocator, stmt, col_count }, writeStreaming);
 }
 
 /// loadInput(allocator, io, db, table_name, input_format, reader, parsed, stderr_writer) → usize

From c27fb837069f16b7bacde385ea663d70961842db Mon Sep 17 00:00:00 2001
From: Victor M Varela <vmvarela@gmail.com>
Date: Sat, 12 Sep 2026 10:18:12 +0200
Subject: [PATCH 2/2] shrink: collapse null guard to one line

---
 src/main.zig | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/src/main.zig b/src/main.zig
index 17193fb..de4435b 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -261,10 +261,7 @@ pub fn execQuery(
     defer _ = c.sqlite3_finalize(stmt);
 
     // ponytail: prepare ";" succeeds with NULL stmt — empty result, no panic
-    if (stmt == null) {
-        if (use_table) return;
-        if (output_format == .markdown) return;
-    }
+    if (stmt == null and (use_table or output_format == .markdown)) return;
 
     const col_count: c_int = if (stmt) |s| c.sqlite3_column_count(s) else 0;