backend: do not crash if GGUF lacks general.architecture

Signed-off-by: Jared Van Bortel <jared@nomic.ai>

gpt4all-backend/gptj.cpp

@@ -786,12 +786,14 @@ const std::vector<LLModel::Token> &GPTJ::endTokens() const
 }
 
 const char *get_arch_name(gguf_context *ctx_gguf) {
-    std::string arch_name;
     const int kid = gguf_find_key(ctx_gguf, "general.architecture");
+    if (kid == -1)
+        throw std::runtime_error("key not found in model: general.architecture");
+
     enum gguf_type ktype = gguf_get_kv_type(ctx_gguf, kid);
-    if (ktype != GGUF_TYPE_STRING) {
-        throw std::runtime_error("ERROR: Can't get general architecture from gguf file.");
-    }
+    if (ktype != GGUF_TYPE_STRING)
+        throw std::runtime_error("key general.architecture has wrong type");
+
     return gguf_get_val_str(ctx_gguf, kid);
 }
 
@@ -824,7 +826,11 @@ DLL_EXPORT char *get_file_arch(const char *fname) {
 
     char *arch = nullptr;
     if (ctx_gguf && gguf_get_version(ctx_gguf) <= 3) {
-        arch = strdup(get_arch_name(ctx_gguf));
+        try {
+            arch = strdup(get_arch_name(ctx_gguf));
+        } catch (const std::runtime_error &) {
+            // cannot read key -> return null
+        }
     }
 
     gguf_free(ctx_gguf);

gpt4all-backend/llamamodel.cpp

@@ -105,12 +105,14 @@ static int llama_sample_top_p_top_k(
 }
 
 const char *get_arch_name(gguf_context *ctx_gguf) {
-    std::string arch_name;
     const int kid = gguf_find_key(ctx_gguf, "general.architecture");
+    if (kid == -1)
+        throw std::runtime_error("key not found in model: general.architecture");
+
     enum gguf_type ktype = gguf_get_kv_type(ctx_gguf, kid);
-    if (ktype != (GGUF_TYPE_STRING)) {
-        throw std::runtime_error("ERROR: Can't get general architecture from gguf file.");
-    }
+    if (ktype != GGUF_TYPE_STRING)
+        throw std::runtime_error("key general.architecture has wrong type");
+
     return gguf_get_val_str(ctx_gguf, kid);
 }
 
@@ -136,13 +138,20 @@ static gguf_context *load_gguf(const char *fname) {
 }
 
 static int32_t get_arch_key_u32(std::string const &modelPath, std::string const &archKey) {
+    int32_t value = -1;
+    std::string arch;
+
     auto * ctx = load_gguf(modelPath.c_str());
     if (!ctx)
-        return -1;
-    std::string arch = get_arch_name(ctx);
+        goto cleanup;
 
-    int32_t value = -1;
-    if (ctx) {
+    try {
+        arch = get_arch_name(ctx);
+    } catch (const std::runtime_error &) {
+        goto cleanup; // cannot read key
+    }
+
+    {
         auto key = arch + "." + archKey;
         int keyidx = gguf_find_key(ctx, key.c_str());
         if (keyidx != -1) {
@@ -152,6 +161,7 @@ static int32_t get_arch_key_u32(std::string const &modelPath, std::string const
         }
     }
 
+cleanup:
     gguf_free(ctx);
     return value;
 }
@@ -244,15 +254,26 @@ bool LLamaModel::isModelBlacklisted(const std::string &modelPath) const {
 }
 
 bool LLamaModel::isEmbeddingModel(const std::string &modelPath) const {
+    bool result = false;
+    std::string arch;
+
     auto *ctx_gguf = load_gguf(modelPath.c_str());
     if (!ctx_gguf) {
         std::cerr << __func__ << ": failed to load GGUF from " <<  modelPath << "\n";
-        return false;
+        goto cleanup;
+    }
+
+    try {
+        arch = get_arch_name(ctx_gguf);
+    } catch (const std::runtime_error &) {
+        goto cleanup; // cannot read key
     }
 
-    std::string arch = get_arch_name(ctx_gguf);
+    result = is_embedding_arch(arch);
+
+cleanup:
     gguf_free(ctx_gguf);
-    return is_embedding_arch(arch);
+    return result;
 }
 
 bool LLamaModel::loadModel(const std::string &modelPath, int n_ctx, int ngl)
@@ -962,16 +983,26 @@ DLL_EXPORT const char *get_build_variant() {
 }
 
 DLL_EXPORT char *get_file_arch(const char *fname) {
-    auto *ctx = load_gguf(fname);
     char *arch = nullptr;
-    if (ctx) {
-        std::string archStr = get_arch_name(ctx);
-        if (is_embedding_arch(archStr) && gguf_find_key(ctx, (archStr + ".pooling_type").c_str()) < 0) {
-            // old bert.cpp embedding model
-        } else {
-            arch = strdup(archStr.c_str());
-        }
+    std::string archStr;
+
+    auto *ctx = load_gguf(fname);
+    if (!ctx)
+        goto cleanup;
+
+    try {
+        archStr = get_arch_name(ctx);
+    } catch (const std::runtime_error &) {
+        goto cleanup; // cannot read key
     }
+
+    if (is_embedding_arch(archStr) && gguf_find_key(ctx, (archStr + ".pooling_type").c_str()) < 0) {
+        // old bert.cpp embedding model
+    } else {
+        arch = strdup(archStr.c_str());
+    }
+
+cleanup:
     gguf_free(ctx);
     return arch;
 }