From a5a578c92ac43f5e305b97972985003bfaa64f01 Mon Sep 17 00:00:00 2001
From: Bogdan Kostic <bogdankostic@web.de>
Date: Thu, 12 Feb 2026 15:57:16 +0100
Subject: [PATCH 1/7] Automatically call warm_up() if model is not loaded in
 FastembedRanker

---
 .../components/rankers/fastembed/ranker.py                     | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/integrations/fastembed/src/haystack_integrations/components/rankers/fastembed/ranker.py b/integrations/fastembed/src/haystack_integrations/components/rankers/fastembed/ranker.py
index 6120bac4a3..11158371ad 100644
--- a/integrations/fastembed/src/haystack_integrations/components/rankers/fastembed/ranker.py
+++ b/integrations/fastembed/src/haystack_integrations/components/rankers/fastembed/ranker.py
@@ -177,8 +177,7 @@ def run(self, query: str, documents: list[Document], top_k: int | None = None) -
             raise ValueError(msg)
 
         if self._model is None:
-            msg = "The ranker model has not been loaded. Please call warm_up() before running."
-            raise RuntimeError(msg)
+            self.warm_up()
 
         fastembed_input_docs = self._prepare_fastembed_input_docs(documents)
 

From 1cda1c19cb0c2203b99d683798f278622b33ada0 Mon Sep 17 00:00:00 2001
From: Bogdan Kostic <bogdankostic@web.de>
Date: Thu, 12 Feb 2026 15:57:32 +0100
Subject: [PATCH 2/7] Remove explicit call to warm_up() in ranker_example.py

---
 integrations/fastembed/examples/ranker_example.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/integrations/fastembed/examples/ranker_example.py b/integrations/fastembed/examples/ranker_example.py
index 593334e905..235fe4f814 100644
--- a/integrations/fastembed/examples/ranker_example.py
+++ b/integrations/fastembed/examples/ranker_example.py
@@ -11,7 +11,6 @@
 ]
 
 ranker = FastembedRanker(model_name="Xenova/ms-marco-MiniLM-L-6-v2")
-ranker.warm_up()
 reranked_documents = ranker.run(query=query, documents=documents)["documents"]
 
 

From ce1e5da28ba593dcf105efa8d58dfa36dbc03a48 Mon Sep 17 00:00:00 2001
From: Bogdan Kostic <bogdankostic@web.de>
Date: Thu, 12 Feb 2026 16:25:40 +0100
Subject: [PATCH 3/7] Add unit tests

---
 .../tests/test_fastembed_document_embedder.py    | 14 ++++++++++++++
 .../fastembed/tests/test_fastembed_ranker.py     | 16 +++++++++++++++-
 .../test_fastembed_sparse_document_embedder.py   | 13 +++++++++++++
 .../tests/test_fastembed_sparse_text_embedder.py | 14 ++++++++++++++
 .../tests/test_fastembed_text_embedder.py        | 14 ++++++++++++++
 5 files changed, 70 insertions(+), 1 deletion(-)

diff --git a/integrations/fastembed/tests/test_fastembed_document_embedder.py b/integrations/fastembed/tests/test_fastembed_document_embedder.py
index 37a7a0c581..9b673f0f01 100644
--- a/integrations/fastembed/tests/test_fastembed_document_embedder.py
+++ b/integrations/fastembed/tests/test_fastembed_document_embedder.py
@@ -281,6 +281,20 @@ def test_embed_metadata(self):
             parallel=None,
         )
 
+    def test_run_calls_warm_up(self):
+        embedder = FastembedDocumentEmbedder()
+        assert embedder.embedding_backend is None
+
+        mock_backend = MagicMock()
+        mock_backend.embed.return_value = [[0.1, 0.2, 0.3]]
+
+        with patch.object(
+            embedder, "warm_up", side_effect=lambda: setattr(embedder, "embedding_backend", mock_backend)
+        ) as mock_warm_up:
+            embedder.run(documents=[Document(content="test document")])
+
+        mock_warm_up.assert_called_once()
+
     @pytest.mark.integration
     def test_run(self):
         embedder = FastembedDocumentEmbedder(
diff --git a/integrations/fastembed/tests/test_fastembed_ranker.py b/integrations/fastembed/tests/test_fastembed_ranker.py
index 0985762613..79fa527dda 100644
--- a/integrations/fastembed/tests/test_fastembed_ranker.py
+++ b/integrations/fastembed/tests/test_fastembed_ranker.py
@@ -2,7 +2,7 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 
-from unittest.mock import MagicMock
+from unittest.mock import MagicMock, patch
 
 import numpy as np
 import pytest
@@ -257,6 +257,20 @@ def test_embed_metadata(self):
             parallel=None,
         )
 
+    def test_run_calls_warm_up(self):
+        """
+        Unit test to check that warm_up is called when run is called for the first time.
+        """
+        ranker = FastembedRanker()
+
+        mock_model = MagicMock()
+        mock_model.rerank.return_value = [0.5]
+
+        with patch.object(ranker, "warm_up", side_effect=lambda: setattr(ranker, "_model", mock_model)) as mock_warm_up:
+            ranker.run(query="test query", documents=[Document(content="test document")])
+
+        mock_warm_up.assert_called_once()
+
     @pytest.mark.integration
     def test_run(self):
         ranker = FastembedRanker(model_name="Xenova/ms-marco-MiniLM-L-6-v2", top_k=2)
diff --git a/integrations/fastembed/tests/test_fastembed_sparse_document_embedder.py b/integrations/fastembed/tests/test_fastembed_sparse_document_embedder.py
index 0b58d818aa..87d1c75375 100644
--- a/integrations/fastembed/tests/test_fastembed_sparse_document_embedder.py
+++ b/integrations/fastembed/tests/test_fastembed_sparse_document_embedder.py
@@ -304,6 +304,19 @@ def test_init_with_model_kwargs_parameters(self):
 
         assert embedder.model_kwargs == bm25_config
 
+    def test_run_calls_warm_up(self):
+        embedder = FastembedSparseDocumentEmbedder()
+
+        mock_backend = MagicMock()
+        mock_backend.embed.return_value = [{"indices": [0], "values": [0.5]}]
+
+        with patch.object(
+            embedder, "warm_up", side_effect=lambda: setattr(embedder, "embedding_backend", mock_backend)
+        ) as mock_warm_up:
+            embedder.run(documents=[Document(content="test document")])
+
+        mock_warm_up.assert_called_once()
+
     @pytest.mark.integration
     def test_run_with_model_kwargs(self):
         """
diff --git a/integrations/fastembed/tests/test_fastembed_sparse_text_embedder.py b/integrations/fastembed/tests/test_fastembed_sparse_text_embedder.py
index c9e3f77130..bb16e24bed 100644
--- a/integrations/fastembed/tests/test_fastembed_sparse_text_embedder.py
+++ b/integrations/fastembed/tests/test_fastembed_sparse_text_embedder.py
@@ -224,6 +224,20 @@ def test_init_with_model_kwargs_parameters(self):
 
         assert embedder.model_kwargs == bm25_config
 
+    def test_run_calls_warm_up(self):
+        embedder = FastembedSparseTextEmbedder()
+        assert embedder.embedding_backend is None
+
+        mock_backend = MagicMock()
+        mock_backend.embed.return_value = [[0.1, 0.2, 0.3]]
+
+        with patch.object(
+            embedder, "warm_up", side_effect=lambda: setattr(embedder, "embedding_backend", mock_backend)
+        ) as mock_warm_up:
+            embedder.run(text="test text")
+
+        mock_warm_up.assert_called_once()
+
     @pytest.mark.integration
     def test_run_with_model_kwargs(self):
         """
diff --git a/integrations/fastembed/tests/test_fastembed_text_embedder.py b/integrations/fastembed/tests/test_fastembed_text_embedder.py
index da969dffa8..52cc051327 100644
--- a/integrations/fastembed/tests/test_fastembed_text_embedder.py
+++ b/integrations/fastembed/tests/test_fastembed_text_embedder.py
@@ -202,6 +202,20 @@ def test_run_wrong_incorrect_format(self):
         with pytest.raises(TypeError, match="FastembedTextEmbedder expects a string as input"):
             embedder.run(text=list_integers_input)
 
+    def test_run_calls_warm_up(self):
+        embedder = FastembedTextEmbedder()
+        assert embedder.embedding_backend is None
+
+        mock_backend = MagicMock()
+        mock_backend.embed.return_value = [[0.1, 0.2, 0.3]]
+
+        with patch.object(
+            embedder, "warm_up", side_effect=lambda: setattr(embedder, "embedding_backend", mock_backend)
+        ) as mock_warm_up:
+            embedder.run(text="test text")
+
+        mock_warm_up.assert_called_once()
+
     @pytest.mark.integration
     def test_run(self):
         embedder = FastembedTextEmbedder(

From 9aef38237876451ad8f7692009cfdb7292b84a81 Mon Sep 17 00:00:00 2001
From: Bogdan Kostic <bogdankostic@web.de>
Date: Thu, 12 Feb 2026 16:40:35 +0100
Subject: [PATCH 4/7] Fix typing issue

---
 .../components/rankers/fastembed/ranker.py                     | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/integrations/fastembed/src/haystack_integrations/components/rankers/fastembed/ranker.py b/integrations/fastembed/src/haystack_integrations/components/rankers/fastembed/ranker.py
index 11158371ad..6f28ddc58c 100644
--- a/integrations/fastembed/src/haystack_integrations/components/rankers/fastembed/ranker.py
+++ b/integrations/fastembed/src/haystack_integrations/components/rankers/fastembed/ranker.py
@@ -178,7 +178,8 @@ def run(self, query: str, documents: list[Document], top_k: int | None = None) -
 
         if self._model is None:
             self.warm_up()
-
+        assert self._model is not None  
+        
         fastembed_input_docs = self._prepare_fastembed_input_docs(documents)
 
         scores = list(

From 88f136b454226db7c56f486e291c0e3dc9cfdd71 Mon Sep 17 00:00:00 2001
From: Bogdan Kostic <bogdankostic@web.de>
Date: Thu, 12 Feb 2026 16:49:10 +0100
Subject: [PATCH 5/7] Fix tying

---
 .../components/rankers/fastembed/ranker.py                   | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/integrations/fastembed/src/haystack_integrations/components/rankers/fastembed/ranker.py b/integrations/fastembed/src/haystack_integrations/components/rankers/fastembed/ranker.py
index 6f28ddc58c..26878387f4 100644
--- a/integrations/fastembed/src/haystack_integrations/components/rankers/fastembed/ranker.py
+++ b/integrations/fastembed/src/haystack_integrations/components/rankers/fastembed/ranker.py
@@ -178,12 +178,11 @@ def run(self, query: str, documents: list[Document], top_k: int | None = None) -
 
         if self._model is None:
             self.warm_up()
-        assert self._model is not None  
-        
+
         fastembed_input_docs = self._prepare_fastembed_input_docs(documents)
 
         scores = list(
-            self._model.rerank(
+            self._model.rerank(  # type: ignore[union-attr]
                 query=query,
                 documents=fastembed_input_docs,
                 batch_size=self.batch_size,

From e704865f0367f84bea3c3ed8806aa92b68248687 Mon Sep 17 00:00:00 2001
From: Bogdan Kostic <bogdankostic@web.de>
Date: Thu, 12 Feb 2026 17:02:57 +0100
Subject: [PATCH 6/7] Update docstrings

---
 .../embedders/fastembed/fastembed_document_embedder.py          | 2 --
 .../embedders/fastembed/fastembed_sparse_document_embedder.py   | 2 --
 .../embedders/fastembed/fastembed_sparse_text_embedder.py       | 1 -
 .../components/embedders/fastembed/fastembed_text_embedder.py   | 1 -
 4 files changed, 6 deletions(-)

diff --git a/integrations/fastembed/src/haystack_integrations/components/embedders/fastembed/fastembed_document_embedder.py b/integrations/fastembed/src/haystack_integrations/components/embedders/fastembed/fastembed_document_embedder.py
index c10b05d8c3..b2c28918dc 100644
--- a/integrations/fastembed/src/haystack_integrations/components/embedders/fastembed/fastembed_document_embedder.py
+++ b/integrations/fastembed/src/haystack_integrations/components/embedders/fastembed/fastembed_document_embedder.py
@@ -29,8 +29,6 @@ class FastembedDocumentEmbedder:
         batch_size=256,
     )
 
-    doc_embedder.warm_up()
-
     # Text taken from PubMed QA Dataset (https://huggingface.co/datasets/pubmed_qa)
     document_list = [
         Document(
diff --git a/integrations/fastembed/src/haystack_integrations/components/embedders/fastembed/fastembed_sparse_document_embedder.py b/integrations/fastembed/src/haystack_integrations/components/embedders/fastembed/fastembed_sparse_document_embedder.py
index f20ce84d20..5fda8ffbbe 100644
--- a/integrations/fastembed/src/haystack_integrations/components/embedders/fastembed/fastembed_sparse_document_embedder.py
+++ b/integrations/fastembed/src/haystack_integrations/components/embedders/fastembed/fastembed_sparse_document_embedder.py
@@ -28,8 +28,6 @@ class FastembedSparseDocumentEmbedder:
         batch_size=32,
     )
 
-    sparse_doc_embedder.warm_up()
-
     # Text taken from PubMed QA Dataset (https://huggingface.co/datasets/pubmed_qa)
     document_list = [
         Document(
diff --git a/integrations/fastembed/src/haystack_integrations/components/embedders/fastembed/fastembed_sparse_text_embedder.py b/integrations/fastembed/src/haystack_integrations/components/embedders/fastembed/fastembed_sparse_text_embedder.py
index 8824458a05..437ad3c7f3 100644
--- a/integrations/fastembed/src/haystack_integrations/components/embedders/fastembed/fastembed_sparse_text_embedder.py
+++ b/integrations/fastembed/src/haystack_integrations/components/embedders/fastembed/fastembed_sparse_text_embedder.py
@@ -28,7 +28,6 @@ class FastembedSparseTextEmbedder:
     sparse_text_embedder = FastembedSparseTextEmbedder(
         model="prithivida/Splade_PP_en_v1"
     )
-    sparse_text_embedder.warm_up()
 
     sparse_embedding = sparse_text_embedder.run(text)["sparse_embedding"]
     ```
diff --git a/integrations/fastembed/src/haystack_integrations/components/embedders/fastembed/fastembed_text_embedder.py b/integrations/fastembed/src/haystack_integrations/components/embedders/fastembed/fastembed_text_embedder.py
index b6e24500f3..d593f2b9b3 100644
--- a/integrations/fastembed/src/haystack_integrations/components/embedders/fastembed/fastembed_text_embedder.py
+++ b/integrations/fastembed/src/haystack_integrations/components/embedders/fastembed/fastembed_text_embedder.py
@@ -24,7 +24,6 @@ class FastembedTextEmbedder:
     text_embedder = FastembedTextEmbedder(
         model="BAAI/bge-small-en-v1.5"
     )
-    text_embedder.warm_up()
 
     embedding = text_embedder.run(text)["embedding"]
     ```

From c3ba2a00e14c7b7a26496ce134ebd5ca9b9a1be3 Mon Sep 17 00:00:00 2001
From: Bogdan Kostic <bogdankostic@web.de>
Date: Fri, 13 Feb 2026 11:09:56 +0100
Subject: [PATCH 7/7] Remove explicit warm_up calls from integration tests

---
 .../fastembed/tests/test_fastembed_document_embedder.py         | 1 -
 integrations/fastembed/tests/test_fastembed_ranker.py           | 1 -
 .../fastembed/tests/test_fastembed_sparse_document_embedder.py  | 2 --
 .../fastembed/tests/test_fastembed_sparse_text_embedder.py      | 1 -
 integrations/fastembed/tests/test_fastembed_text_embedder.py    | 1 -
 5 files changed, 6 deletions(-)

diff --git a/integrations/fastembed/tests/test_fastembed_document_embedder.py b/integrations/fastembed/tests/test_fastembed_document_embedder.py
index 9b673f0f01..61be6f4409 100644
--- a/integrations/fastembed/tests/test_fastembed_document_embedder.py
+++ b/integrations/fastembed/tests/test_fastembed_document_embedder.py
@@ -300,7 +300,6 @@ def test_run(self):
         embedder = FastembedDocumentEmbedder(
             model="BAAI/bge-small-en-v1.5",
         )
-        embedder.warm_up()
 
         doc = Document(content="Parton energy loss in QCD matter")
 
diff --git a/integrations/fastembed/tests/test_fastembed_ranker.py b/integrations/fastembed/tests/test_fastembed_ranker.py
index 79fa527dda..3d78991def 100644
--- a/integrations/fastembed/tests/test_fastembed_ranker.py
+++ b/integrations/fastembed/tests/test_fastembed_ranker.py
@@ -274,7 +274,6 @@ def test_run_calls_warm_up(self):
     @pytest.mark.integration
     def test_run(self):
         ranker = FastembedRanker(model_name="Xenova/ms-marco-MiniLM-L-6-v2", top_k=2)
-        ranker.warm_up()
 
         query = "Who is maintaining Qdrant?"
         documents = [
diff --git a/integrations/fastembed/tests/test_fastembed_sparse_document_embedder.py b/integrations/fastembed/tests/test_fastembed_sparse_document_embedder.py
index 87d1c75375..8b80b884f1 100644
--- a/integrations/fastembed/tests/test_fastembed_sparse_document_embedder.py
+++ b/integrations/fastembed/tests/test_fastembed_sparse_document_embedder.py
@@ -330,7 +330,6 @@ def test_run_with_model_kwargs(self):
             model="Qdrant/bm42-all-minilm-l6-v2-attentions",
             model_kwargs=bm42_config,
         )
-        embedder.warm_up()
 
         doc = Document(content="Example content using BM42")
 
@@ -349,7 +348,6 @@ def test_run(self):
         embedder = FastembedSparseDocumentEmbedder(
             model="prithivida/Splade_PP_en_v1",
         )
-        embedder.warm_up()
 
         doc = Document(content="Parton energy loss in QCD matter")
 
diff --git a/integrations/fastembed/tests/test_fastembed_sparse_text_embedder.py b/integrations/fastembed/tests/test_fastembed_sparse_text_embedder.py
index bb16e24bed..0a7936dad6 100644
--- a/integrations/fastembed/tests/test_fastembed_sparse_text_embedder.py
+++ b/integrations/fastembed/tests/test_fastembed_sparse_text_embedder.py
@@ -272,7 +272,6 @@ def test_run(self):
         embedder = FastembedSparseTextEmbedder(
             model="prithivida/Splade_PP_en_v1",
         )
-        embedder.warm_up()
 
         text = "Parton energy loss in QCD matter"
 
diff --git a/integrations/fastembed/tests/test_fastembed_text_embedder.py b/integrations/fastembed/tests/test_fastembed_text_embedder.py
index 52cc051327..008e905cab 100644
--- a/integrations/fastembed/tests/test_fastembed_text_embedder.py
+++ b/integrations/fastembed/tests/test_fastembed_text_embedder.py
@@ -221,7 +221,6 @@ def test_run(self):
         embedder = FastembedTextEmbedder(
             model="BAAI/bge-small-en-v1.5",
         )
-        embedder.warm_up()
 
         text = "Parton energy loss in QCD matter"