lobster_bazel: bazel plugin for lobster

BUILD

@@ -29,6 +29,7 @@ copyright_checker(
         "starpls",
         "tools",
         "plantuml",
+        "lobster_bazel",
 
         # Add other directories/files you want to check
     ],

MODULE.bazel

@@ -151,6 +151,15 @@ pip.parse(
 )
 use_repo(pip, "pip_tooling")
 
+pip.parse(
+    envsubst = ["PIP_INDEX_URL"],
+    extra_pip_args = ["--index-url=${PIP_INDEX_URL:-https://pypi.org/simple/}"],
+    hub_name = "pip_lobster_bazel",
+    python_version = PYTHON_VERSION,
+    requirements_lock = "//lobster_bazel:requirements.txt",
+)
+use_repo(pip, "pip_lobster_bazel")
+
 ###############################################################################
 # Multitool Hub (for ruff, pyright, actionlint, etc.)
 ###############################################################################

lobster_bazel/BUILD

@@ -0,0 +1,32 @@
+# *******************************************************************************
+# Copyright (c) 2026 Contributors to the Eclipse Foundation
+#
+# See the NOTICE file(s) distributed with this work for additional
+# information regarding copyright ownership.
+#
+# This program and the accompanying materials are made available under the
+# terms of the Apache License Version 2.0 which is available at
+# https://www.apache.org/licenses/LICENSE-2.0
+#
+# SPDX-License-Identifier: Apache-2.0
+# *******************************************************************************
+load("@rules_python//python:defs.bzl", "py_binary", "py_library")
+
+py_binary(
+    name = "lobster-bazel",
+    srcs = [
+        "parse_source_files.py",
+    ],
+    main = "parse_source_files.py",
+    visibility = [
+        "//visibility:public",
+    ],
+    deps = [
+        "@pip_lobster_bazel//bmw_lobster",
+    ],
+)
+
+exports_files([
+    "requirements.in",
+    "requirements.txt",
+])

lobster_bazel/README.md

@@ -0,0 +1,131 @@
+# Tracing to Source Files (Bazel / Source Code Linker)
+
+## Overview
+
+`lobster-bazel` scans source files for inline tracing tags and produces a
+`.lobster` file in the `lobster-imp-trace` format. It is designed for use in
+Bazel-based projects where the build system can provide lists of source files to
+scan, but the tool itself is not Bazel-specific and can be used with any build
+system that can produce file-list inputs.
+
+Supported file types (automatically detected by extension):
+
+| Extension            | Language  | Comment sign |
+|----------------------|-----------|--------------|
+| `.c`, `.cc`, `.cpp`, `.cxx`, `.h`, `.hh`, `.hpp`, `.hxx` | C/C++  | `//` |
+| `.rs`                | Rust      | `//` |
+| `.py`                | Python    | `#` |
+| `.bzl`               | Starlark  | `#` |
+| `.trlc`, `.rsl`      | TRLC      | `#` |
+
+Files with unsupported extensions are silently skipped; the run continues and
+reports the number of items extracted from the remaining files.
+
+## Adding tracing tags to source files
+
+Add a single-line comment **at the start of the line** with the tracing tag
+attribute and the requirement ID:
+
+```python
+# Python example
+def process():
+    # req-traceability: COMP_REQ_001
+    pass
+```
+
+```cpp
+// C++ example
+void process() {
+    // req-traceability: COMP_REQ_001
+}
+```
+
+```rust
+// Rust example
+fn process() {
+    // req-traceability: COMP_REQ_001
+}
+```
+
+> **Note:** The tag pattern must appear at the start of the (stripped) line.
+> Inline comments at the end of a code statement are intentionally **not**
+> matched to avoid false positives.
+
+The tag attribute (e.g. `req-traceability`) is configurable via `--tag`.
+The default tag used by the `lobster_linker` Bazel rule is `lobster-trace`.
+
+## Creating lobster files
+
+The tool reads **file-list files** as positional arguments. Each file-list file
+contains one source file path per line. This design integrates naturally with
+Bazel's `$(locations ...)` expansion or any tool that can dump a list of files.
+
+```sh
+$ lobster-bazel --output impl.lobster \
+    --tag req-traceability \
+    source_files.txt
+```
+
+Where `source_files.txt` contains:
+
+```
+src/module_a.py
+src/module_b.rs
+include/module_c.hpp
+```
+
+Multiple file-list files and multiple `--tag` values are supported:
+
+```sh
+$ lobster-bazel --output impl.lobster \
+    --tag req-traceability \
+    --tag req-Id \
+    sources_a.txt sources_b.txt
+```
+
+An optional `--namespace` argument controls the namespace prefix for the
+generated tags (default: `source`):
+
+```sh
+$ lobster-bazel --output impl.lobster \
+    --tag req-traceability \
+    --namespace impl \
+    source_files.txt
+```
+
+### Error behaviour
+
+- **Unsupported file extension**: the file is skipped with a warning; the run
+  continues.
+- **Unreadable or missing source file**: an error is logged and the file is
+  skipped; the run continues and exits with code 0.
+- **Unreadable file-list file**: a fatal error is logged and the tool exits
+  with code 1.
+
+## Bazel integration
+
+When using Bazel, use the `lobster_linker` rule from `lobster.bzl`:
+
+```starlark
+load("@lobster//:lobster.bzl", "lobster_linker", "lobster_test")
+
+lobster_linker(
+    name = "impl_trace",
+    srcs = [
+        "//src:my_library",
+        "//src:my_binary",
+    ],
+    tracing_tags = ["req-traceability"],
+)
+```
+
+The `lobster_linker` rule automatically collects all source files from the
+listed targets and passes them to `lobster-bazel`. The output is exposed as a
+`LobsterProvider` so it can be consumed by `lobster_test`.
+
+The `subrule_lobster_linker` subrule is also exported for composing the linker
+into other custom Bazel rules:
+
+```starlark
+load("@lobster//:lobster.bzl", "subrule_lobster_linker")
+```

lobster_bazel/lobster_bazel.bzl

@@ -0,0 +1,19 @@
+# *******************************************************************************
+# Copyright (c) 2026 Contributors to the Eclipse Foundation
+#
+# See the NOTICE file(s) distributed with this work for additional
+# information regarding copyright ownership.
+#
+# This program and the accompanying materials are made available under the
+# terms of the Apache License Version 2.0 which is available at
+# https://www.apache.org/licenses/LICENSE-2.0
+#
+# SPDX-License-Identifier: Apache-2.0
+# *******************************************************************************
+load("//lobster_bazel/private:lobster_linker.bzl", _lobster_linker = "lobster_linker", _subrule_lobster_linker = "subrule_lobster_linker")
+
+# Re-export LobsterProvider so it can be loaded from this file
+def lobster_linker(**kwargs):
+    _lobster_linker(**kwargs)
+
+subrule_lobster_linker = _subrule_lobster_linker