{"record":{"id":"37be3c271d0247d9","repo":"valyala/fasthttp","slug":"cannot-determine-absolute-path-for-q-v","errorCode":null,"errorMessage":"cannot determine absolute path for %q: %v","messagePattern":"cannot determine absolute path for %q: (.+?)","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"fs.go","lineNumber":1712,"sourceCode":"\t}\n\n\tcompressedFilePath := h.filePathToCompressed(filePath)\n\n\tif _, ok := h.filesystem.(*osFS); !ok {\n\t\treturn h.newCompressedFSFileCache(f, fileInfo, compressedFilePath, fileEncoding)\n\t}\n\n\tif compressedFilePath != filePath {\n\t\tif err := os.MkdirAll(filepath.Dir(compressedFilePath), 0o750); err != nil {\n\t\t\treturn nil, err\n\t\t}\n\t}\n\tcompressedFilePath += h.compressedFileSuffixes[fileEncoding]\n\n\tabsPath, err := filepath.Abs(compressedFilePath)\n\tif err != nil {\n\t\t_ = f.Close()\n\t\treturn nil, fmt.Errorf(\"cannot determine absolute path for %q: %v\", compressedFilePath, err)\n\t}\n\n\tflock := acquireFileLock(absPath)\n\tflock.mu.Lock()\n\tdefer func() {\n\t\tflock.mu.Unlock()\n\t\treleaseFileLock(absPath, flock)\n\t}()\n\treturn h.compressFileNolock(f, fileInfo, filePath, compressedFilePath, fileEncoding)\n}\n\nfunc (h *fsHandler) compressFileNolock(\n\tf fs.File, fileInfo fs.FileInfo, filePath, compressedFilePath, fileEncoding string,\n) (*fsFile, error) {\n\t// Attempt to open compressed file created by another concurrent\n\t// goroutine.\n\t// It is safe opening such a file, since the file creation\n\t// is guarded by file mutex - see getFileLock call.","sourceCodeStart":1694,"sourceCodeEnd":1730,"githubUrl":"https://github.com/valyala/fasthttp/blob/c96f600972c6f4a7a30d664257b340ebe9d60124/fs.go#L1694-L1730","documentation":"During on-the-fly file compression, fasthttp computes the absolute path of the compressed cache file (original path + compressed suffix) so it can acquire a per-path file lock. filepath.Abs failed, which is rare and only happens when Getwd fails on a relative path. The opened source file is closed and the wrapped filepath error is reported with %v.","triggerScenarios":"Calling the FS handler with a relative file path (no leading '/' and no AbsPath configured) while the process's working directory has been deleted, or in environments where os.Getwd fails (removed cwd, restricted sandbox).","commonSituations":"Container/sandbox where the working directory was deleted at runtime; serving files with relative paths after a chdir-based deploy wiped the original cwd; running tests that os.Chdir into temp dirs later removed.","solutions":["Use absolute paths: set FS.Root to an absolute directory or pass absolute file paths to SendFile.","Ensure the process working directory exists (start the binary from a valid dir; avoid deleting the cwd).","Configure FS.AbsPathToLocalPath / AbsPath so fasthttp resolves to absolute paths itself.","Inspect the wrapped error: a Getwd failure like 'no such file or directory' confirms the cwd problem."],"exampleFix":"// before\nfs := &fasthttp.FS{Root: \"static\"}\n// after\nabsRoot, err := filepath.Abs(\"static\")\nif err != nil { panic(err) }\nfs := &fasthttp.FS{Root: absRoot}","handlingStrategy":"validation","validationCode":"abs, err := filepath.Abs(root)\nif err != nil {\n    panic(\"working directory invalid: \" + err.Error())\n}\nfs := &fasthttp.FS{Root: abs}","typeGuard":null,"tryCatchPattern":"if strings.Contains(err.Error(), \"cannot determine absolute path\") {\n    // restart process from a valid working directory or use absolute roots\n}","preventionTips":["Always configure FS.Root with an absolute path.","Never delete the process working directory at runtime.","In containers, set WORKDIR to a persistent, existing directory."],"tags":["filesystem","fasthttp","filepath","compression-cache"],"backgroundTag":"filepath-abs-failed","analyzedSha":"c96f600972c6f4a7a30d664257b340ebe9d60124","analyzedAt":"2026-08-31T22:48:28.265Z","contentChangedAt":null,"schemaVersion":2},"datasetVersion":"2026-09-08T05:18:18.240Z"}