Remove version headers from explain files and delete version consistency test

- Remove "-- Generated by ClickHouse X.X.X.X" header from all explain files
- Delete TestExplainVersionConsistency test
- Update regenerate-explain to not add version headers

Author: claude

cmd/regenerate-explain/main.go

@@ -586,9 +586,6 @@ func processTest(testDir string, dryRun bool) error {
 		return nil
 	}
 
-	// Generate version header comment
-	versionHeader := fmt.Sprintf("-- Generated by ClickHouse %s\n", requiredVersion)
-
 	var stmtErrors []string
 	for i, stmt := range statements {
 		stmtNum := i + 1 // 1-indexed
@@ -608,8 +605,7 @@ func processTest(testDir string, dryRun bool) error {
 			outputPath = filepath.Join(testDir, fmt.Sprintf("explain_%d.txt", stmtNum))
 		}
 
-		// Write with version header
-		content := versionHeader + explain + "\n"
+		content := explain + "\n"
 		if err := os.WriteFile(outputPath, []byte(content), 0644); err != nil {
 			return fmt.Errorf("writing %s: %w", outputPath, err)
 		}

parser/parser_test.go

@@ -268,173 +268,6 @@ func TestParser(t *testing.T) {
 	}
 }
 
-// TestExplainVersionConsistency ensures all explain*.txt files have the same ClickHouse version header.
-// This test:
-// - Scans all explain*.txt files in testdata/
-// - Checks each file for a "-- Generated by ClickHouse X.X.X.X" header
-// - Skips files in test directories with parse_error, skip, or explain:false metadata
-// - Reports files without version headers
-// - Reports if multiple different versions are found
-// - Passes only when all files have the same version header
-func TestExplainVersionConsistency(t *testing.T) {
-	testdataDir := "testdata"
-
-	// Cache for metadata per test directory
-	metadataCache := make(map[string]*testMetadata)
-	getMetadata := func(testDir string) *testMetadata {
-		if meta, ok := metadataCache[testDir]; ok {
-			return meta
-		}
-		metaPath := filepath.Join(testDir, "metadata.json")
-		content, err := os.ReadFile(metaPath)
-		if err != nil {
-			metadataCache[testDir] = nil
-			return nil
-		}
-		var meta testMetadata
-		if err := json.Unmarshal(content, &meta); err != nil {
-			metadataCache[testDir] = nil
-			return nil
-		}
-		metadataCache[testDir] = &meta
-		return &meta
-	}
-
-	// shouldSkipDir returns true if this test directory should be skipped for version checking
-	shouldSkipDir := func(testDir string) bool {
-		meta := getMetadata(testDir)
-		if meta == nil {
-			return false
-		}
-		// Skip if parse_error (contains intentionally invalid SQL)
-		if meta.ParseError {
-			return true
-		}
-		// Skip if test is marked to skip entirely
-		if meta.Skip {
-			return true
-		}
-		// Skip if explain is explicitly disabled
-		if meta.Explain != nil && !*meta.Explain {
-			return true
-		}
-		return false
-	}
-
-	// shouldSkipFile returns true if this specific explain file should be skipped
-	// (e.g., it's in explain_todo)
-	shouldSkipFile := func(testDir, filename string) bool {
-		meta := getMetadata(testDir)
-		if meta == nil || meta.ExplainTodo == nil {
-			return false
-		}
-		// Convert filename to statement key
-		// explain.txt -> stmt1, explain_2.txt -> stmt2, etc.
-		stmtKey := "stmt1"
-		if strings.HasPrefix(filename, "explain_") && strings.HasSuffix(filename, ".txt") {
-			numStr := strings.TrimSuffix(strings.TrimPrefix(filename, "explain_"), ".txt")
-			stmtKey = "stmt" + numStr
-		}
-		return meta.ExplainTodo[stmtKey]
-	}
-
-	// Find all explain*.txt files, skipping directories with parse_error/skip/explain:false
-	var explainFiles []string
-	var skippedDirs = make(map[string]bool)
-	var skippedFiles int
-	err := filepath.Walk(testdataDir, func(path string, info os.FileInfo, err error) error {
-		if err != nil {
-			return err
-		}
-		if !info.IsDir() && strings.HasPrefix(info.Name(), "explain") && strings.HasSuffix(info.Name(), ".txt") {
-			testDir := filepath.Dir(path)
-			if shouldSkipDir(testDir) {
-				skippedDirs[testDir] = true
-				return nil
-			}
-			if shouldSkipFile(testDir, info.Name()) {
-				skippedFiles++
-				return nil
-			}
-			explainFiles = append(explainFiles, path)
-		}
-		return nil
-	})
-	if err != nil {
-		t.Fatalf("Failed to walk testdata directory: %v", err)
-	}
-
-	if len(skippedDirs) > 0 || skippedFiles > 0 {
-		t.Logf("Skipped %d test directories with parse_error/skip/explain:false metadata, %d files in explain_todo", len(skippedDirs), skippedFiles)
-	}
-
-	if len(explainFiles) == 0 {
-		t.Skip("No explain*.txt files found")
-	}
-
-	// Track versions and files without headers
-	versionToFiles := make(map[string][]string)
-	var filesWithoutHeaders []string
-
-	versionPattern := "-- Generated by ClickHouse "
-
-	for _, path := range explainFiles {
-		content, err := os.ReadFile(path)
-		if err != nil {
-			t.Errorf("Failed to read %s: %v", path, err)
-			continue
-		}
-
-		lines := strings.Split(string(content), "\n")
-		if len(lines) == 0 {
-			filesWithoutHeaders = append(filesWithoutHeaders, path)
-			continue
-		}
-
-		firstLine := lines[0]
-		if !strings.HasPrefix(firstLine, versionPattern) {
-			filesWithoutHeaders = append(filesWithoutHeaders, path)
-			continue
-		}
-
-		// Extract version from "-- Generated by ClickHouse X.X.X.X"
-		version := strings.TrimPrefix(firstLine, versionPattern)
-		versionToFiles[version] = append(versionToFiles[version], path)
-	}
-
-	// Report findings
-	if len(filesWithoutHeaders) > 0 {
-		t.Errorf("Found %d files without version headers:", len(filesWithoutHeaders))
-		// Show first 10 files as examples
-		limit := 10
-		if len(filesWithoutHeaders) < limit {
-			limit = len(filesWithoutHeaders)
-		}
-		for _, path := range filesWithoutHeaders[:limit] {
-			t.Errorf("  - %s", path)
-		}
-		if len(filesWithoutHeaders) > 10 {
-			t.Errorf("  ... and %d more", len(filesWithoutHeaders)-10)
-		}
-	}
-
-	if len(versionToFiles) > 1 {
-		t.Errorf("Found %d different ClickHouse versions:", len(versionToFiles))
-		for version, files := range versionToFiles {
-			t.Errorf("  Version %q: %d files", version, len(files))
-		}
-	}
-
-	if len(filesWithoutHeaders) > 0 || len(versionToFiles) != 1 {
-		t.FailNow()
-	}
-
-	// Log the consistent version
-	for version := range versionToFiles {
-		t.Logf("All %d explain files have consistent version: %s", len(explainFiles), version)
-	}
-}
-
 // BenchmarkParser benchmarks the parser performance using a complex query
 func BenchmarkParser(b *testing.B) {
 	query := `

parser/testdata/00001_count_hits/explain.txt

@@ -1,4 +1,3 @@
--- Generated by ClickHouse 25.8.13.73
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 2)

parser/testdata/00001_select_1/explain.txt

@@ -1,4 +1,3 @@
--- Generated by ClickHouse 25.8.13.73
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 1)

parser/testdata/00002_count_visits/explain.txt

@@ -1,4 +1,3 @@
--- Generated by ClickHouse 25.8.13.73
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 2)

parser/testdata/00002_system_numbers/explain.txt

@@ -1,2 +1 @@
--- Generated by ClickHouse 25.8.13.73
 Set

parser/testdata/00002_system_numbers/explain_10.txt

@@ -1,4 +1,3 @@
--- Generated by ClickHouse 25.8.13.73
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 3)

parser/testdata/00002_system_numbers/explain_11.txt

@@ -1,4 +1,3 @@
--- Generated by ClickHouse 25.8.13.73
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 3)

parser/testdata/00002_system_numbers/explain_12.txt

@@ -1,4 +1,3 @@
--- Generated by ClickHouse 25.8.13.73
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 3)

parser/testdata/00002_system_numbers/explain_13.txt

@@ -1,4 +1,3 @@
--- Generated by ClickHouse 25.8.13.73
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 3)