docs: add documentation for reachability analysis (#2211)

Signed-off-by: ziad hany <ziadhany2016@gmail.com>

Author: ziadhany

docs/built-in-pipelines.rst

@@ -48,6 +48,14 @@ Analyze Docker Windows Image
 
 .. _pipeline_benchmark_purls:
 
+Analyze Symbol Reachability
+----------------------------
+.. autoclass:: scanpipe.pipelines.analyze_symbols_reachability.SymbolReachability()
+    :members:
+    :member-order: bysource
+
+.. _analyze_symbols_reachability:
+
 Benchmark PURLs (addon)
 -----------------------
 

docs/images/tutorial-web-ui-analyze-symbol-reachability.png

@@ -47,6 +47,7 @@ Learn via practical step-by-step guides.
 - :ref:`tutorial_vulnerablecode_integration`
 - :ref:`tutorial_web_ui_symbol_and_string_collection`
 - :ref:`tutorial_cli_end_to_end_scanning_to_dejacode`
+- :ref:`tutorial_analyze_symbols_reachability`
 
 .. rst-class:: column column2 bottom-left
 
@@ -116,6 +117,7 @@ Indices and tables
     tutorial_vulnerablecode_integration
     tutorial_web_ui_symbol_and_string_collection
     tutorial_cli_end_to_end_scanning_to_dejacode
+    tutorial_analyze_symbols_reachability
     scanpipe-concepts
     built-in-pipelines
     custom-pipelines

docs/index.rst

@@ -134,3 +134,8 @@ Windows
 -------
 .. automodule:: scanpipe.pipes.windows
     :members:
+
+Reachability
+-------------
+.. automodule:: scanpipe.pipes.reachability
+    :members:

docs/scanpipe-pipes.rst

@@ -0,0 +1,106 @@
+.. _tutorial_analyze_symbols_reachability:
+
+Analyze Symbol Reachability
+===========================
+
+In this tutorial, we will introduce the add-on pipeline that can be used to
+analyze symbols reachability from codebase resources.
+
+Requirements
+------------
+
+To successfully complete this tutorial, you first need to:
+
+- Install **ScanCode.io** locally :ref:`installation`.
+- Have an existing project resource affected
+  by a vulnerability advisory that has a corresponding fix commit.
+- Run the ``find_vulnerabilities`` pipeline :ref:`tutorial_vulnerablecode_integration`.
+
+Reachability Status
+-------------------
+
+The reachability status can have one of the following values:
+
+- ``REACHABLE``: "yes"
+  (We found evidence that the vulnerable symbol is reachable and the vulnerable code exists.)
+- ``UNKNOWN``: "unknown"
+  (We cannot determine reachability with confidence.)
+- ``NOT_REACHABLE``: "no"
+  (We found evidence that the vulnerable symbol is not reachable.)
+
+
+Run the ``analyze_symbols_reachability`` pipeline
+-------------------------------------------------
+
+- Open any existing project containing a few resources.
+- Click the **"Add pipeline"** button and select the **"analyze_symbols_reachability"**
+  pipeline from the dropdown list.
+- Select **"Execute pipeline now"** and click **"Add pipeline"** to start the
+  reachability analysis.
+- Once the pipeline run completes successfully, you can reach the **Resources** list view
+  by clicking the count number under the **"RESOURCES"** header.
+- Click on one of the affected code files and navigate to
+  the **Extra** tab to view the ``symbols_reachability``.
+
+.. image:: images/tutorial-web-ui-analyze-symbol-reachability.png
+
+- The pipeline output also includes a JSON file containing the reachability
+  status for each advisory and resource, including the overall reachability
+  status (e.g., ``reachability-2026-08-18-15-12-51.json``).
+
+.. code-block:: json
+    :emphasize-lines: 2
+
+    {
+      "purl": "pkg:pypi/b2sdk@1.14.0",
+      "advisories": [
+        {
+          "advisory_uid": "pypa/b2sdk/PYSEC-2022-33",
+          "is_reachable": "yes",
+          "details": [
+            {
+              "resource_path": "b2sdk-1.14.0/b2sdk/account_info/sqlite_account_info.py",
+              "patch": {
+                "vcs_url": "https://github.com/backblaze/b2-sdk-python",
+                "commit_hash": "62476638986e5b6d7459aca5ef8ce220760226e0"
+              },
+              "is_reachable": "yes",
+              "tool_details": [
+                {
+                  "symbol_name": "SqliteAccountInfo._create_database",
+                  "is_called": true,
+                  "is_defined": true,
+                  "is_imported": false,
+                  "is_exact": true,
+                  "reachable_from": [
+                    "SqliteAccountInfo._validate_database"
+                  ]
+                },
+                {
+                  "symbol_name": "SqliteAccountInfo",
+                  "is_called": false,
+                  "is_defined": true,
+                  "is_imported": false,
+                  "is_exact": true,
+                  "reachable_from": []
+                }
+              ],
+              "vulnerable_symbols": [
+                "SqliteAccountInfo",
+                "SqliteAccountInfo._create_database"
+              ],
+              "fixed_symbols": [
+                "SqliteAccountInfo",
+                "SqliteAccountInfo._create_database"
+              ]
+            },
+              // ... more details
+            ]
+          }
+        }
+
+.. note::
+    An advisory is considered ``REACHABLE`` if it is reachable through at least
+    one resource. If no resource is ``REACHABLE`` and at least one result is
+    ``UNKNOWN``, the advisory status is ``UNKNOWN``. Otherwise, its status is
+    ``NOT_REACHABLE``.