Move header files from include to src.

plugin/sycl/predictor/predictor.cc

@@ -1,5 +1,5 @@
 /*!
- * Copyright by Contributors 2017-2025
+ * Copyright by Contributors 2017-2026
  */
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wtautological-constant-compare"
@@ -17,7 +17,7 @@
 #include "dmlc/registry.h"
 
 #include "xgboost/tree_model.h"
-#include "xgboost/predictor.h"
+#include "../../../src/predictor/predictor.h"
 #include "xgboost/tree_updater.h"
 #include "../../../src/common/timer.h"
 

src/c_api/c_api.cc

@@ -1,5 +1,5 @@
 /**
- * Copyright 2014-2025, XGBoost Contributors
+ * Copyright 2014-2026, XGBoost Contributors
  */
 #include "xgboost/c_api.h"
 
@@ -29,6 +29,7 @@
 #include "../data/proxy_dmatrix.h"       // for DMatrixProxy
 #include "../data/simple_dmatrix.h"      // for SimpleDMatrix
 #include "../encoder/types.h"            // for Overloaded
+#include "../learner.h"                  // for Learner, PredictionType
 #include "c_api_error.h"                 // for xgboost_CHECK_C_ARG_PTR, API_END, API_BEGIN
 #include "c_api_utils.h"                 // for RequiredArg, OptionalArg, GetMissing, CastDM...
 #include "dmlc/base.h"                   // for BeginPtr
@@ -42,9 +43,7 @@
 #include "xgboost/global_config.h"       // for GlobalConfiguration, GlobalConfigThreadLocal...
 #include "xgboost/host_device_vector.h"  // for HostDeviceVector
 #include "xgboost/json.h"                // for Json, get, Integer, IsA, Boolean, String
-#include "xgboost/learner.h"             // for Learner, PredictionType
 #include "xgboost/logging.h"             // for LOG_FATAL, LogMessageFatal, CHECK, LogCheck_EQ
-#include "xgboost/predictor.h"           // for PredictionCacheEntry
 #include "xgboost/span.h"                // for Span
 #include "xgboost/string_view.h"         // for StringView, operator<<
 #include "xgboost/version_config.h"      // for XGBOOST_VER_MAJOR, XGBOOST_VER_MINOR, XGBOOS...

src/c_api/c_api.cu

@@ -1,5 +1,5 @@
 /**
- * Copyright 2019-2025, XGBoost Contributors
+ * Copyright 2019-2026, XGBoost Contributors
  */
 #include <thrust/transform.h>  // for transform
 
@@ -13,7 +13,7 @@
 #include "xgboost/c_api.h"
 #include "xgboost/data.h"
 #include "xgboost/json.h"
-#include "xgboost/learner.h"
+#include "../learner.h"  // for Learner
 #if defined(XGBOOST_USE_NCCL)
 #include <nccl.h>
 #endif  // defined(XGBOOST_USE_NCCL)

src/c_api/c_api_utils.h

@@ -1,5 +1,5 @@
 /**
- * Copyright 2021-2024, XGBoost Contributors
+ * Copyright 2021-2026, XGBoost Contributors
  */
 #ifndef XGBOOST_C_API_C_API_UTILS_H_
 #define XGBOOST_C_API_C_API_UTILS_H_
@@ -19,7 +19,7 @@
 #include "xgboost/data.h"         // DMatrix
 #include "xgboost/feature_map.h"  // for FeatureMap
 #include "xgboost/json.h"
-#include "xgboost/learner.h"
+#include "../learner.h"  // for Learner
 #include "xgboost/linalg.h"  // ArrayInterfaceHandler, MakeTensorView, ArrayInterfaceStr
 #include "xgboost/logging.h"
 #include "xgboost/string_view.h"  // StringView

src/common/api_entry.h

@@ -1,17 +1,18 @@
 /**
- * Copyright 2016-2023 by XGBoost contributors
+ * Copyright 2016-2026, XGBoost contributors
  */
 #ifndef XGBOOST_COMMON_API_ENTRY_H_
 #define XGBOOST_COMMON_API_ENTRY_H_
-#include <string>               // std::string
-#include <vector>               // std::vector
 
-#include "xgboost/base.h"       // GradientPair,bst_ulong
-#include "xgboost/predictor.h"  // PredictionCacheEntry
+#include <string>  // for string
+#include <vector>  // for vector
+
+#include "../predictor/predictor.h"  // PredictionCacheEntry
+#include "xgboost/base.h"            // GradientPair,bst_ulong
 
 namespace xgboost {
 /**
- * \brief entry to to easily hold returning information
+ * @brief entry to to easily hold returning information
  */
 struct XGBAPIThreadLocalEntry {
   /*! \brief result holder for returning string */

include/xgboost/cache.h → src/common/cache.h

@@ -1,9 +1,7 @@
 /**
- * Copyright 2023 by XGBoost contributors
+ * Copyright 2023-2026, XGBoost contributors
  */
-#ifndef XGBOOST_CACHE_H_
-#define XGBOOST_CACHE_H_
-
+#pragma once
 #include <xgboost/logging.h>  // for CHECK_EQ, CHECK
 
 #include <cstddef>            // for size_t
@@ -201,4 +199,3 @@ class DMatrixCache {
   }
 };
 }  // namespace xgboost
-#endif  // XGBOOST_CACHE_H_

src/data/data.cc

@@ -1,5 +1,5 @@
 /**
- * Copyright 2015-2025, XGBoost Contributors
+ * Copyright 2015-2026, XGBoost Contributors
  * \file data.cc
  */
 #include "xgboost/data.h"
@@ -52,7 +52,7 @@
 #include "xgboost/base.h"                     // for bst_group_t, bst_idx_t, bst_float, bst_ulong
 #include "xgboost/context.h"                  // for Context
 #include "xgboost/host_device_vector.h"       // for HostDeviceVector
-#include "xgboost/learner.h"                  // for HostDeviceVector
+#include "../learner.h"                       // for Learner
 #include "xgboost/linalg.h"                   // for Tensor, Stack, TensorView, Vector, ArrayInte...
 #include "xgboost/logging.h"                  // for Error, LogCheck_EQ, CHECK, CHECK_EQ, LOG
 #include "xgboost/span.h"                     // for Span, operator!=, SpanIterator

src/gbm/gblinear.cc

@@ -1,5 +1,5 @@
 /**
- * Copyright 2014-2025, XGBoost Contributors
+ * Copyright 2014-2026, XGBoost Contributors
  * \file gblinear.cc
  * \brief Implementation of Linear booster, with L1/L2 regularization: Elastic Net
  *        the update rule is parallel coordinate descent (shotgun)
@@ -17,13 +17,13 @@
 #include "../common/threading_utils.h"
 #include "../common/timer.h"
 #include "gblinear_model.h"
-#include "xgboost/gbm.h"
+#include "gbm.h"  // for GradientContainer
 #include "xgboost/json.h"
-#include "xgboost/learner.h"
+#include "../learner.h"  // for LearnerModelParam
 #include "xgboost/linalg.h"
 #include "xgboost/linear_updater.h"
 #include "xgboost/logging.h"
-#include "xgboost/predictor.h"
+#include "../predictor/predictor.h"  // for Predictor
 
 namespace xgboost::gbm {
 DMLC_REGISTRY_FILE_TAG(gblinear);

src/gbm/gblinear_model.h

@@ -1,10 +1,10 @@
 /**
- * Copyright 2018-2025, XGBoost Contributors
+ * Copyright 2018-2026, XGBoost Contributors
  */
 #pragma once
 #include <dmlc/io.h>
 #include <dmlc/parameter.h>
-#include <xgboost/learner.h>
+#include "../learner.h"  // for LearnerModelParam
 
 #include <vector>
 #include <string>

src/gbm/gbm.cc

@@ -1,16 +1,16 @@
 /**
- * Copyright 2015-2025, XGBoost Contributors
+ * Copyright 2015-2026, XGBoost Contributors
  * \file gbm.cc
  * \brief Registry of gradient boosters.
  */
-#include "xgboost/gbm.h"
+#include "gbm.h"
 
 #include <dmlc/registry.h>
 
 #include <string>
 
 #include "xgboost/context.h"
-#include "xgboost/learner.h"
+#include "../learner.h"  // for LearnerModelParam
 
 namespace dmlc {
 DMLC_REGISTRY_ENABLE(::xgboost::GradientBoosterReg);

include/xgboost/gbm.h → src/gbm/gbm.h

@@ -1,12 +1,11 @@
 /**
- * Copyright 2014-2025, XGBoost Contributors
+ * Copyright 2014-2026, XGBoost Contributors
  * \file gbm.h
  * \brief Interface of gradient booster,
  *  that learns through gradient statistics.
  * \author Tianqi Chen
  */
-#ifndef XGBOOST_GBM_H_
-#define XGBOOST_GBM_H_
+#pragma once
 
 #include <dmlc/registry.h>
 #include <xgboost/base.h>
@@ -196,4 +195,3 @@ struct GradientBoosterReg
       ::dmlc::Registry< ::xgboost::GradientBoosterReg>::Get()->__REGISTER__(Name)
 
 }  // namespace xgboost
-#endif  // XGBOOST_GBM_H_

src/gbm/gbtree.cc

@@ -24,16 +24,16 @@
 #include "../common/threading_utils.h"
 #include "../common/timer.h"
 #include "../data/proxy_dmatrix.h"  // for DMatrixProxy, HostAdapterDispatch
+#include "gbm.h"
 #include "gbtree_model.h"
 #include "xgboost/base.h"
 #include "xgboost/data.h"
-#include "xgboost/gbm.h"
 #include "xgboost/host_device_vector.h"
 #include "xgboost/json.h"
 #include "xgboost/logging.h"
 #include "xgboost/model.h"
 #include "xgboost/objective.h"
-#include "xgboost/predictor.h"
+#include "../predictor/predictor.h"  // for Predictor
 #include "xgboost/string_view.h"  // for StringView
 #include "xgboost/tree_model.h"   // for RegTree
 #include "xgboost/tree_updater.h"

src/gbm/gbtree.h

@@ -1,5 +1,5 @@
 /**
- * Copyright 2014-2025, XGBoost Contributors
+ * Copyright 2014-2026, XGBoost Contributors
  * \file gbtree.cc
  * \brief gradient boosted tree implementation.
  * \author Tianqi Chen
@@ -20,15 +20,15 @@
 #include "../common/timer.h"
 #include "../tree/param.h"      // TrainParam
 #include "../tree/tree_view.h"  // for WalkTree
+#include "gbm.h"                // for GradientBooster
 #include "gbtree_model.h"
 #include "xgboost/base.h"
 #include "xgboost/data.h"
-#include "xgboost/gbm.h"
 #include "xgboost/host_device_vector.h"
 #include "xgboost/json.h"
 #include "xgboost/logging.h"
 #include "xgboost/parameter.h"
-#include "xgboost/predictor.h"
+#include "../predictor/predictor.h"  // for Predictor
 #include "xgboost/tree_updater.h"
 
 namespace xgboost {

src/gbm/gbtree_model.cc

@@ -1,5 +1,5 @@
 /**
- * Copyright 2019-2025, XGBoost Contributors
+ * Copyright 2019-2026, XGBoost Contributors
  */
 #include "gbtree_model.h"
 
@@ -11,7 +11,7 @@
 #include "../common/threading_utils.h"  // for ParallelFor
 #include "xgboost/context.h"            // for Context
 #include "xgboost/json.h"               // for Json, get, Integer, Array, FromJson, ToJson, Json...
-#include "xgboost/learner.h"            // for LearnerModelParam
+#include "../learner.h"                 // for LearnerModelParam
 #include "xgboost/logging.h"            // for LogCheck_EQ, CHECK_EQ, CHECK
 #include "xgboost/tree_model.h"         // for RegTree
 

src/gbm/gbtree_model.h

@@ -1,5 +1,5 @@
 /**
- * Copyright 2017-2025, XGBoost Contributors
+ * Copyright 2017-2026, XGBoost Contributors
  *
  * @file gbtree_model.h
  */
@@ -15,7 +15,7 @@
 #include "../common/threading_utils.h"
 #include "../data/cat_container.h"  // for CatContainer
 #include "xgboost/context.h"
-#include "xgboost/learner.h"
+#include "../learner.h"  // for LearnerModelParam
 #include "xgboost/model.h"
 #include "xgboost/tree_model.h"
 

src/learner.cc

@@ -4,47 +4,47 @@
  * \brief Implementation of learning algorithm.
  * \author Tianqi Chen
  */
-#include "xgboost/learner.h"
-
-#include <dmlc/io.h>                      // for Stream
-#include <dmlc/parameter.h>               // for FieldEntry, DMLC_DECLARE_FIELD, Parameter, DMLC...
-#include <dmlc/thread_local.h>            // for ThreadLocalStore
-
-#include <algorithm>                      // for equal, max, transform, sort, find_if, all_of
-#include <atomic>                         // for atomic
-#include <cctype>                         // for isalpha, isspace
-#include <cmath>                          // for isnan, isinf
-#include <cstdint>                        // for int32_t, uint32_t, int64_t, uint64_t
-#include <cstdlib>                        // for atoi
-#include <cstring>                        // for memcpy, size_t, memset
-#include <iomanip>                        // for operator<<, setiosflags
-#include <iterator>                       // for back_insert_iterator, distance, back_inserter
-#include <limits>                         // for numeric_limits
-#include <memory>                         // for allocator, unique_ptr, shared_ptr, operator==
-#include <mutex>                          // for mutex, lock_guard
-#include <sstream>                        // for operator<<, basic_ostream, basic_ostream::opera...
-#include <stack>                          // for stack
-#include <string>                         // for basic_string, char_traits, operator<, string
-#include <system_error>                   // for errc
-#include <unordered_map>                  // for operator!=, unordered_map
-#include <utility>                        // for pair, as_const, move, swap
-#include <vector>                         // for vector
+#include "learner.h"
+
+#include <dmlc/io.h>            // for Stream
+#include <dmlc/parameter.h>     // for FieldEntry, DMLC_DECLARE_FIELD, Parameter, DMLC...
+#include <dmlc/thread_local.h>  // for ThreadLocalStore
+
+#include <algorithm>      // for equal, max, transform, sort, find_if, all_of
+#include <atomic>         // for atomic
+#include <cctype>         // for isalpha, isspace
+#include <cmath>          // for isnan, isinf
+#include <cstdint>        // for int32_t, uint32_t, int64_t, uint64_t
+#include <cstdlib>        // for atoi
+#include <cstring>        // for memcpy, size_t, memset
+#include <iomanip>        // for operator<<, setiosflags
+#include <iterator>       // for back_insert_iterator, distance, back_inserter
+#include <limits>         // for numeric_limits
+#include <memory>         // for allocator, unique_ptr, shared_ptr, operator==
+#include <mutex>          // for mutex, lock_guard
+#include <sstream>        // for operator<<, basic_ostream, basic_ostream::opera...
+#include <stack>          // for stack
+#include <string>         // for basic_string, char_traits, operator<, string
+#include <system_error>   // for errc
+#include <unordered_map>  // for operator!=, unordered_map
+#include <utility>        // for pair, as_const, move, swap
+#include <vector>         // for vector
 
 #include "collective/aggregator.h"        // for ApplyWithLabels
 #include "collective/communicator-inl.h"  // for Allreduce, Broadcast, GetRank, IsDistributed
 #include "common/api_entry.h"             // for XGBAPIThreadLocalEntry
-#include "common/param_array.h"           // for ParamArray
 #include "common/charconv.h"              // for to_chars, to_chars_result, NumericLimits, from_...
 #include "common/error_msg.h"             // for MaxFeatureSize, WarnOldSerialization, ...
 #include "common/io.h"                    // for PeekableInStream, ReadAll, FixedSizeStream, Mem...
 #include "common/observer.h"              // for TrainingObserver
+#include "common/param_array.h"           // for ParamArray
 #include "common/random.h"                // for GlobalRandom
 #include "common/timer.h"                 // for Monitor
 #include "common/version.h"               // for Version
+#include "gbm/gbm.h"                      // for GradientBooster
 #include "xgboost/base.h"                 // for Args, GradientPair, bst_feature_t
 #include "xgboost/context.h"              // for Context
 #include "xgboost/data.h"                 // for DMatrix, MetaInfo
-#include "xgboost/gbm.h"                  // for GradientBooster
 #include "xgboost/global_config.h"        // for GlobalConfiguration, GlobalConfigThreadLocalStore
 #include "xgboost/host_device_vector.h"   // for HostDeviceVector
 #include "xgboost/json.h"                 // for Json, get, Object, String, IsA, Array, ToJson
@@ -53,7 +53,7 @@
 #include "xgboost/metric.h"               // for Metric
 #include "xgboost/objective.h"            // for ObjFunction
 #include "xgboost/parameter.h"            // for DECLARE_FIELD_ENUM_CLASS, XGBoostParameter
-#include "xgboost/predictor.h"            // for PredictionContainer, PredictionCacheEntry
+#include "predictor/predictor.h"          // for PredictionContainer, PredictionCacheEntry
 #include "xgboost/string_view.h"          // for operator<<, StringView
 #include "xgboost/task.h"                 // for ObjInfo
 

include/xgboost/learner.h → src/learner.h

@@ -1,12 +1,11 @@
 /**
- * Copyright 2015-2025, XGBoost Contributors
+ * Copyright 2015-2026, XGBoost Contributors
  *
  * \brief Learner interface that integrates objective, gbm and evaluation together.
  *  This is the user facing XGBoost training module.
  * \author Tianqi Chen
  */
-#ifndef XGBOOST_LEARNER_H_
-#define XGBOOST_LEARNER_H_
+#pragma once
 
 #include <dmlc/io.h>           // for Serializable
 #include <xgboost/base.h>      // for bst_feature_t, bst_target_t, bst_float, Args, GradientPair, ..
@@ -352,6 +351,4 @@ struct LearnerModelParam {
   /* \brief Whether this parameter is initialized with LearnerModelParamLegacy. */
   [[nodiscard]] bool Initialized() const { return num_feature != 0 && num_output_group != 0; }
 };
-
 }  // namespace xgboost
-#endif  // XGBOOST_LEARNER_H_