fix(gsession): atomic write in SetSession to prevent concurrent read race (#4792) - #4814
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waterWang wants to merge 2 commits into
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fix(gsession): atomic write in SetSession to prevent concurrent read race (#4792)#4814waterWang wants to merge 2 commits into
waterWang wants to merge 2 commits into
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…f#4787) When Result.Structs / Model.Scan is called with a *[]map[string]interface{} pointer, the destination element type is reflect.Map, but converter.Structs routes it through c.Struct which expects a struct type. This causes GetCachedStructInfo to return nil for non-struct types, silently producing empty maps. Fix: add a reflect.Map branch that calls c.MapToMap for each element instead of c.Struct. This matches the behavior of gconv.Scan which already handles map-slice conversion via MapToMaps.
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| return err | ||
| // Build content with 8-byte timestamp prefix (same format as before). | ||
| timestamp := gbinary.EncodeInt64(gtime.TimestampMilli()) | ||
| data := make([]byte, 8+len(content)) |
| // Atomic write: write to temp file first, then rename. | ||
| // This prevents concurrent readers from seeing an empty/partial file. | ||
| tmpPath := path + ".tmp" | ||
| if err := os.WriteFile(tmpPath, data, os.ModePerm); err != nil { |
| if _, err = file.Write(content); err != nil { | ||
| err = gerror.Wrapf(err, `write data failed to file "%s"`, path) | ||
| return err | ||
| if err := os.Rename(tmpPath, path); err != nil { |
| if _, err = file.Write(content); err != nil { | ||
| err = gerror.Wrapf(err, `write data failed to file "%s"`, path) | ||
| return err | ||
| if err := os.Rename(tmpPath, path); err != nil { |
| err = gerror.Wrapf(err, `write data failed to file "%s"`, path) | ||
| return err | ||
| if err := os.Rename(tmpPath, path); err != nil { | ||
| os.Remove(tmpPath) |
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Fix: Atomic write in
SetSessionto prevent concurrent read raceDescription
StorageFile.SetSessionuses a non-atomic file write pattern (open withO_TRUNCthen two separateWritecalls), creating a race window where concurrent readers see an empty or partially-written file.Root Cause
The write path:
O_TRUNC— immediately empties itfile.Write(timestamp)— writes 8 bytesfile.Write(content)— writes JSON bodyBetween steps 1 and 3, any concurrent reader calling
GetSessionsees a file with ≤8 bytes and returnsnil— the user appears "not logged in".Fix
Replace the
O_TRUNC+ twoWrite()calls with atomic write via temp file +os.Rename():.tmpfileos.Rename()the temp file to the target pathos.Rename()is atomic on the same filesystem (POSIX guarantee), so readers always see a complete file.Testing
os/gsession/gsession_z_unit_storage_file_test.gocover the session lifecycleos.Renameis used elsewhere in the Go ecosystem for atomic file writes (e.g.,os.WriteFileitself is atomic on most systems, but we use temp+rename for explicit POSIX atomicity)Fixes #4792