From 07e0df959e587755d9e2fb5420050657e85aa3f9 Mon Sep 17 00:00:00 2001
From: Garrett D'Amore <garrett@damore.org>
Date: Tue, 13 Jan 2026 23:36:05 -0800
Subject: [PATCH] ci: generate coverage data for codecov.

This adds a new lst2codecov tool that converts DMD *.lst files
into a coverage.json file formatted using the documented format
from codecov, so that we can upload it to codecov.
---
 .github/workflows/build.yml            |  4 ++
 tools/lst2codecov/dub.json             |  9 ++++
 tools/lst2codecov/source/lst2codecov.d | 64 ++++++++++++++++++++++++++
 3 files changed, 77 insertions(+)
 create mode 100644 tools/lst2codecov/dub.json
 create mode 100644 tools/lst2codecov/source/lst2codecov.d

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 9f4899d..ad0e541 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -46,6 +46,10 @@ jobs:
             cd ../..
           done
 
+      - name: Convert code coverage
+        run: |
+          dub run --root tools/lst2codecov
+
       - name: Upload coverage to Codecov
         uses: codecov/codecov-action@v5
         with:
diff --git a/tools/lst2codecov/dub.json b/tools/lst2codecov/dub.json
new file mode 100644
index 0000000..6f476c3
--- /dev/null
+++ b/tools/lst2codecov/dub.json
@@ -0,0 +1,9 @@
+{
+  "copyright": "Copyright 2026 Garrett D'Amore",
+  "description": "Convert DMD .lst files to CodeCov JSON",
+  "name": "lst2codecov",
+  "targetType": "executable",
+  "targetName": "lst2codecov",
+  "targetPath": "bin",
+  "mainSourceFile": "source/lst2codecov.d"
+}
diff --git a/tools/lst2codecov/source/lst2codecov.d b/tools/lst2codecov/source/lst2codecov.d
new file mode 100644
index 0000000..80f5408
--- /dev/null
+++ b/tools/lst2codecov/source/lst2codecov.d
@@ -0,0 +1,64 @@
+/**
+ * Lst2CodeCov module implements logic to convert DMD *.lst coverage
+ * files into simple codecov custom JSON.
+ *
+ * Copyright: Copyright 2026 Garrett D'Amore
+ * Authors: Garrett D'Amore
+ * License:
+ *   Distributed under the Boost Software License, Version 1.0.
+ *   (See accompanying file LICENSE or https://www.boost.org/LICENSE_1_0.txt)
+ *   SPDX-License-Identifier: BSL-1.0
+ */
+module lst2codecov;
+
+alias FileData = int[string];
+
+// coverage is map of filenames -> line number (as string) -> count
+static int[string][string] coverage;
+
+void main()
+{
+    import std.conv;
+    import std.string;
+    import std.file;
+    import std.json;
+
+    // Approach - find all the *.lst files.
+    // The files have a format of:
+    // count|source
+    // (count might be empty, if nothing is executed)
+    // (count might be 0000000 if the line is missed)
+    // last line is "filename is %% covered" or "filename has no code"
+    // There will not be a | character on that last line.
+
+    // for now shallow only
+    foreach (entry; dirEntries(".", "*.lst", SpanMode.shallow))
+    {
+        auto lineNo = 0;
+        auto fileName = entry.name;
+        int[string] counts;
+        auto lst = readText(entry.name);
+        foreach (line; lst.splitLines())
+        {
+            lineNo++;
+            auto parts = line.split("|");
+            if (parts.length == 1)
+            {
+                parts = line.split(" ");
+                fileName = parts[0].idup;
+            }
+            else
+            {
+                auto countStr = parts[0].strip;
+                if (countStr.isNumeric()) {
+                    counts[lineNo.to!string] = countStr.to!int;
+                }
+            }
+        }
+        coverage[fileName] = counts;
+    }
+
+    JSONValue js = ["coverage" : JSONValue(coverage)];
+
+    write("coverage.json", js.toString);
+}