### Summary
Slovak and Czech datasets are effectively BM25-blind today. The tokenizer only keeps ASCII letter runs whole, so every accented word is fragmented before indexing (`škola` -> `š kola`) and the keyword leg of hybrid search never matches. Neither language has a Snowball stemmer either, so the analyzer inherits whatever stemmer the previously processed dataset left behind.
Co-authored-by: mcivan <martin.civan@nases.gov.sk>
### What problem does this PR solve?
Repeated stemmer initialization created new Snowball environments
without releasing the previous ones, causing native memory usage to grow
continuously during retrieval.
This change reuses the existing environment when the language is
unchanged and releases the previous environment before switching
languages.
### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)
## Problem
The Go server build pipeline (`build.sh` + CMake + CGO bindings) was
tested on Ubuntu only. On macOS arm64 with Homebrew it fails in five
orthogonal places. None of these require platform-specific code paths —
the same source builds on both Linux and Darwin after these fixes.
## Reproduction (before)
```
$ uname -a
Darwin … 25.4.0 arm64
$ brew install cmake pcre2 simde
$ bash build.sh
…
error: 'simde/x86/sse4.1.h' file not found
error: implicit instantiation of undefined template 'std::basic_istringstream<char>'
error: no matching function for call to 'Join'
…
clang: error: no such file or directory: '/usr/local/lib/libpcre2-8.a'
```
## Fix (5 small, orthogonal changes)
### 1. `internal/cpp/CMakeLists.txt` — find Homebrew + libpcre2-8
portably
- Detect Apple platforms via `if(APPLE)`, call `brew --prefix` once, add
`${HOMEBREW_PREFIX}/include` and `${HOMEBREW_PREFIX}/lib`. No effect on
Linux.
- Replace the literal `libpcre2-8.a` link token (which only the Linux
linker finds in `/usr/local/lib` by default) with
`find_library(PCRE2_LIB NAMES pcre2-8 REQUIRED)`. Works on
`/usr/lib/x86_64-linux-gnu` (Debian/Ubuntu), `/usr/local/lib` (Intel Mac
& legacy Linux), `/opt/homebrew/lib` (Apple Silicon).
### 2. `internal/cpp/wordnet_lemmatizer.cpp` +
`internal/cpp/rag_analyzer.cpp` — explicit `#include <sstream>`
libstdc++ (Linux) pulls `<sstream>` in transitively via `<fstream>`;
libc++ (Apple Clang) doesn't, so the existing `std::istringstream` /
`std::ostringstream` uses fail to compile on macOS. One-line include in
each file.
### 3. `internal/cpp/rag_analyzer.cpp` — `Join` template overload fix
`Join(tokens, start, tokens.size(), delim)` at line 146 passes `size_t`
to an `int` parameter. C++23 strict mode in Apple Clang refuses the
implicit narrowing and reports the 4-arg overload as a substitution
failure, leaving the call ambiguous between the 3-arg and 4-arg
templates. Fix: explicit `static_cast<int>(tokens.size())`. Behaviour
identical on libstdc++ — the narrowing was always intentional.
### 4. `internal/binding/rag_analyzer.go` — split darwin CGO LDFLAGS
The existing `#cgo darwin LDFLAGS: ... /usr/local/lib/libpcre2-8.a` only
matches Intel Macs. Apple Silicon Homebrew installs to `/opt/homebrew`.
Split into `darwin,arm64` and `darwin,amd64` build constraints with the
right absolute path on each.
### 5. `build.sh` — accept Homebrew path in the pcre2 sanity check
The sanity check looked at two Linux paths only and then fell through to
`sudo apt -y install libpcre2-dev` on failure. Added
`/opt/homebrew/lib/libpcre2-8.a`, and on Darwin failure now exits
cleanly with the right `brew install pcre2` hint instead of trying
`apt`.
## Verified
- `bash build.sh` now completes on macOS arm64 (Apple Silicon, brew 4.x,
cmake 4.x, Apple Clang 17, Go 1.25, pcre2 10.x, simde 0.8.x).
- Produced binaries: `bin/server_main`, `bin/admin_server`,
`bin/ragflow_cli`.
- `bin/server_main` boots, connects MySQL, runs migrations, loads the 64
model provider configs cleanly.
- Still builds on Linux — the CMake additions are inside an `if(APPLE)`
guard, the `find_library` call matches Linux paths too, the build.sh
check still tries `apt` when not on Darwin.
## Out of scope
The Go server itself currently fails at runtime when not pointing at
Elasticsearch (`Failed to initialize doc engine: failed to ping
Elasticsearch`), but that's the placeholder Infinity engine documented
in `internal/engine/README.md` — unrelated to this build patchset.
---
Happy to split this into smaller PRs if you'd prefer (one per file). The
five changes are independent.
buua436
CCLUCKY
Martin Civáňandmcivan
Anupam Mediratta
qinling0210
Jack
Zhichang Yu
sapienza yoan