refactor(gomongo): return native Go types instead of JSON strings #22

h3n4l · 2026-01-27T07:26:34Z

Summary

Refactor Result type to return native Go types instead of JSON strings
Add types.OperationType enum in new types/ package as single source of truth
Result.Value is now []any containing native Go types (bson.D, string, int64, bool)
Result.Operation indicates the operation type for type assertions

Return Types by Operation

Operation	Value Type
Find, Aggregate, GetIndexes, GetCollectionInfos	`[]bson.D`
FindOne, FindOneAnd*	0 or 1 `bson.D`
CountDocuments, EstimatedDocumentCount	`int64`
Distinct	values of various types
ShowDatabases, ShowCollections, GetCollectionNames	`string`
Write operations	`bson.D` with operation result
Admin operations	`bson.D` with `{ok: 1}`, `bool`, or `string`

Test Plan

All existing tests updated and passing
Linting passes with 0 issues

🤖 Generated with Claude Code

Change Result type from returning JSON strings to native Go types for better type safety and usability. Key changes: - Add types.OperationType enum in new types/ package (single source of truth) - Result.Value is now []any containing native Go types (bson.D, string, int64, bool) instead of JSON-encoded strings - Result.Operation indicates the operation type for callers to determine expected element types in Value slice Return types by operation: - Find/Aggregate/GetIndexes/GetCollectionInfos: []bson.D - FindOne/FindOneAnd*: 0 or 1 bson.D - CountDocuments/EstimatedDocumentCount: int64 - Distinct: values of various types - ShowDatabases/ShowCollections/GetCollectionNames: strings - Write operations: bson.D with operation result - Admin operations: bson.D with {ok: 1} or bool/string Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Copilot

Pull request overview

Refactors gomongo execution results to return native Go/BSON values (instead of Extended JSON strings) and introduces a shared types.OperationType enum to make result typing explicit.

Changes:

Replace Result.Rows/RowCount with Result.Operation + Result.Value []any across public API, executor, and tests.
Add types.OperationType as the shared operation enum and update translator/executor to use it.
Update README and test suite to assert on native Go types (e.g., bson.D, int64, string, bool).

Reviewed changes

Copilot reviewed 19 out of 19 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
write_test.go	Updates write-operation tests to assert against `Result.Value` and BSON-native values.
unicode_test.go	Updates unicode tests to assert against BSON-native values rather than JSON strings.
types/operation_type.go	Adds shared `types.OperationType` enum as a single source of truth.
internal/translator/visitor.go	Switches parsed operation type assignment to `types.OperationType`.
internal/translator/types.go	Updates `translator.Operation.OpType` to use `types.OperationType`.
internal/translator/bson_helpers_test.go	Updates helper tests to validate typed BSON values in `Result.Value`.
internal/testutil/container_test.go	Adjusts test expectations to use `len(result.Value)` instead of `RowCount`.
internal/executor/write.go	Returns write results as BSON-native documents with `Operation` set.
internal/executor/server.go	Returns show-databases results as `[]string` in `Value`.
internal/executor/executor.go	Refactors internal executor `Result` and dispatch to use `types.OperationType`.
internal/executor/database.go	Refactors show/get collection operations to return native types.
internal/executor/collection.go	Refactors find/aggregate/distinct/count/indexes paths to return native types.
internal/executor/admin.go	Refactors admin operation results to native types (string/bool/bson.D).
executor.go	Wires public `gomongo.Result` to internal executor result shape.
database_test.go	Updates DB-level tests to validate `Result.Value` typing/contents.
collection_test.go	Adds helpers for converting `Value` elements to JSON for string-based assertions; updates many tests.
client.go	Updates public `Result` shape and documents expected element types by operation.
admin_test.go	Updates admin tests to check native values and simplifies helpers.
README.md	Updates docs/examples to explain and demonstrate `Result.Operation` + `Result.Value`.

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Copilot · 2026-01-27T07:29:38Z

internal/executor/collection.go

+	var docs []bson.D
 	for cursor.Next(ctx) {
-		var doc bson.M
+		var doc bson.D
 		if err := cursor.Decode(&doc); err != nil {
 			return nil, fmt.Errorf("decode failed: %w", err)
 		}
-
-		// Marshal to Extended JSON (Relaxed)
-		jsonBytes, err := bson.MarshalExtJSONIndent(doc, false, false, "", "  ")
-		if err != nil {
-			return nil, fmt.Errorf("marshal failed: %w", err)
-		}
-		rows = append(rows, string(jsonBytes))
+		docs = append(docs, doc)
 	}

 	if err := cursor.Err(); err != nil {
 		return nil, fmt.Errorf("cursor error: %w", err)
 	}

+	// Convert []bson.D to []any
+	values := make([]any, len(docs))
+	for i, doc := range docs {
+		values[i] = doc
+	}


executeFind currently collects results into a []bson.D and then allocates/copies into a []any. This adds an extra allocation and full slice copy for large result sets. You can append decoded documents directly into a []any (or preallocate the []any when you can estimate size) to avoid the intermediate slice.

Copilot · 2026-01-27T07:29:38Z

README.md

+        doc := val.(bson.D)
+        fmt.Printf("%+v\n", doc)
    }
+
+    // For countDocuments(), single element is int64
+    countResult, _ := gc.Execute(ctx, "mydb", `db.users.countDocuments({})`)
+    count := countResult.Value[0].(int64)


The README usage snippet uses unchecked type assertions (val.(bson.D) and countResult.Value[0].(int64)). This can panic if the statement changes or an error path returns a different shape. Since README code is often copied verbatim, it would be safer to show checked assertions (", ok := ...") and basic error handling for the countResult call.

Suggested change

doc := val.(bson.D)

fmt.Printf("%+v\n", doc)

}

// For countDocuments(), single element is int64

countResult, _ := gc.Execute(ctx, "mydb", `db.users.countDocuments({})`)

count := countResult.Value[0].(int64)

doc, ok := val.(bson.D)

if !ok {

log.Printf("unexpected document type %T\n", val)

continue

}

fmt.Printf("%+v\n", doc)

}

// For countDocuments(), single element is int64

countResult, err := gc.Execute(ctx, "mydb", `db.users.countDocuments({})`)

if err != nil {

log.Fatal(err)

}

if len(countResult.Value) == 0 {

log.Fatal("no count result returned")

}

count, ok := countResult.Value[0].(int64)

if !ok {

log.Fatalf("unexpected count type %T\n", countResult.Value[0])

}

Copilot · 2026-01-27T07:29:38Z

admin_test.go

+// containsDatabaseName checks if the values contain the given database name.
+// Values can be strings (from show dbs) or bson.D documents.
+func containsDatabaseName(values []any, name string) bool {


The comment above containsDatabaseName says values can be strings or bson.D documents, but the implementation only checks for string values. Either update the comment to match the actual behavior (show dbs returns strings) or add bson.D handling for consistency with containsCollectionName.

Copilot · 2026-01-27T07:29:39Z

internal/translator/bson_helpers_test.go

 // These tests verify BSON helper function conversions through the full pipeline.
 // Since the helper functions are not exported, we test them end-to-end.

+// getDocField extracts a string representation of a field from a bson.D document


The getDocField doc comment is inaccurate: it says it "extracts a string representation" but the function returns the field's value as any. Please update the comment to reflect what the helper actually returns (e.g., "extracts the value of a field from a bson.D").

Suggested change

// getDocField extracts a string representation of a field from a bson.D document

// getDocField extracts the value of a field from a bson.D document.

Copilot · 2026-01-27T07:29:39Z

write_test.go

+func valueToJSONWrite(v any) string {
+	bytes, err := bson.MarshalExtJSONIndent(v, false, false, "", "  ")
+	if err != nil {
+		return fmt.Sprintf("%v", v)
+	}
+	return string(bytes)
+}


write_test.go introduces valueToJSONWrite, but the repo already has an equivalent helper (valueToJSON / valuesToStrings) in collection_test.go within the same gomongo_test package. This duplication makes it easier for helpers to drift and increases maintenance cost. Consider reusing the existing helper (or moving a single helper into a shared *_test.go/util file under internal/testutil) and removing this per-file variant.

Copilot · 2026-01-27T07:29:39Z

unicode_test.go

+func valueToJSONUnicode(v any) string {
+	bytes, err := bson.MarshalExtJSONIndent(v, false, false, "", "  ")
+	if err != nil {
+		return fmt.Sprintf("%v", v)
+	}
+	return string(bytes)
+}


unicode_test.go adds valueToJSONUnicode, which is functionally the same as the existing valueToJSON helper in collection_test.go (same package). Duplicating these helpers across test files increases maintenance overhead. Prefer reusing the existing helper (or centralizing a single helper in a shared test util file) and deleting this per-file copy.

- Optimize executeFind to append directly to []any, avoiding intermediate slice - Use checked type assertions in README examples for safer error handling - Fix misleading comment on containsDatabaseName (values are always strings) - Fix misleading comment on getDocField helper in tests - Consolidate duplicate valueToJSON test helpers into single shared function

Copilot AI review requested due to automatic review settings January 27, 2026 07:26

Copilot started reviewing on behalf of h3n4l January 27, 2026 07:26 View session

Copilot AI reviewed Jan 27, 2026

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rebelice approved these changes Jan 27, 2026

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h3n4l merged commit ca70aee into main Jan 27, 2026
2 checks passed

h3n4l deleted the vk/6444-in-gomongo-libra branch January 27, 2026 07:42

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refactor(gomongo): return native Go types instead of JSON strings #22

refactor(gomongo): return native Go types instead of JSON strings #22

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-        doc := val.(bson.D)
-        fmt.Printf("%+v\n", doc)
-    }
-    // For countDocuments(), single element is int64
-    countResult, _ := gc.Execute(ctx, "mydb", `db.users.countDocuments({})`)
-    count := countResult.Value[0].(int64)
+        doc, ok := val.(bson.D)
+        if !ok {
+            log.Printf("unexpected document type %T\n", val)
+            continue
+        }
+        fmt.Printf("%+v\n", doc)
+    }
+    // For countDocuments(), single element is int64
+    countResult, err := gc.Execute(ctx, "mydb", `db.users.countDocuments({})`)
+    if err != nil {
+        log.Fatal(err)
+    }
+    if len(countResult.Value) == 0 {
+        log.Fatal("no count result returned")
+    }
+    count, ok := countResult.Value[0].(int64)
+    if !ok {
+        log.Fatalf("unexpected count type %T\n", countResult.Value[0])
+    }

	// getDocField extracts a string representation of a field from a bson.D document
	// getDocField extracts the value of a field from a bson.D document.

refactor(gomongo): return native Go types instead of JSON strings #22

refactor(gomongo): return native Go types instead of JSON strings #22

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h3n4l commented Jan 27, 2026

Summary

Return Types by Operation

Test Plan

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