Fix build for Swift Package Index by dynamically detecting FreeTDS and guarding imports

Author: vkuttyp

.spi.yml

@@ -1,27 +1,5 @@
 version: 1
 builder:
   configs:
-    # Linux builds — apt-install FreeTDS before building.
-    # macOS builds are excluded: SPI's macOS runners cannot pre-install
-    # Homebrew packages, so pkg-config cannot locate FreeTDS at build time.
-    # macOS users install via: brew install freetds
+    - platform: macos-spm
     - platform: linux
-      swift_version: '5.10'
-      linux_packages:
-        - freetds-dev
-        - pkg-config
-    - platform: linux
-      swift_version: '6.0'
-      linux_packages:
-        - freetds-dev
-        - pkg-config
-    - platform: linux
-      swift_version: '6.1'
-      linux_packages:
-        - freetds-dev
-        - pkg-config
-    - platform: linux
-      swift_version: '6.2'
-      linux_packages:
-        - freetds-dev
-        - pkg-config

Package.swift

@@ -1,5 +1,55 @@
 // swift-tools-version: 5.9
 import PackageDescription
+import Foundation
+
+// SPI Runners do not have FreeTDS installed. 
+// We detect its presence to avoid Clang scanner errors on SPI.
+let hasFreeTDS: Bool = {
+    // Manual override for local testing
+    if ProcessInfo.processInfo.environment["SKIP_FREETDS"] != nil { return false }
+    
+    let standardPaths = [
+        "/opt/homebrew/include/sybdb.h",      // macOS Apple Silicon
+        "/usr/local/include/sybdb.h",         // macOS Intel
+        "/usr/include/sybdb.h",               // Linux (Standard)
+        "/usr/include/freetds/sybdb.h",       // Linux (Alternative)
+        "/opt/homebrew/opt/freetds/include/sybdb.h" // Brew opt path
+    ]
+    return standardPaths.contains { FileManager.default.fileExists(atPath: $0) }
+}()
+
+var packageTargets: [Target] = [
+    .target(
+        name: "SQLClientSwift",
+        dependencies: hasFreeTDS ? ["CFreeTDS"] : [],
+        path: "Sources/SQLClientSwift",
+        swiftSettings: [
+            .enableExperimentalFeature("StrictConcurrency=complete"),
+        ] + (hasFreeTDS ? [.define("FREETDS_FOUND")] : []),
+        linkerSettings: [
+            .linkedLibrary("sybdb", .when(platforms: [.linux]))
+        ]
+    ),
+    .testTarget(
+        name: "SQLClientSwiftTests",
+        dependencies: ["SQLClientSwift"],
+        path: "Tests/SQLClientSwiftTests"
+    ),
+]
+
+if hasFreeTDS {
+    packageTargets.append(
+        .systemLibrary(
+            name: "CFreeTDS",
+            path: "Sources/CFreeTDS",
+            pkgConfig: "freetds",
+            providers: [
+                .brew(["freetds"]),
+                .apt(["freetds-dev"]),
+            ]
+        )
+    )
+}
 
 let package = Package(
     name: "SQLClientSwift",
@@ -12,35 +62,5 @@ let package = Package(
             targets: ["SQLClientSwift"]
         ),
     ],
-    targets: [
-        // systemLibrary uses pkg-config to find FreeTDS at build time.
-        // No hardcoded paths, no unsafeFlags — works as an SPM dependency.
-        //   macOS : brew install freetds && brew install pkg-config
-        //   Linux : sudo apt install freetds-dev
-        .systemLibrary(
-            name: "CFreeTDS",
-            path: "Sources/CFreeTDS",
-            pkgConfig: "freetds",
-            providers: [
-                .brew(["freetds"]),
-                .apt(["freetds-dev"]),
-            ]
-        ),
-        .target(
-            name: "SQLClientSwift",
-            dependencies: ["CFreeTDS"],
-            path: "Sources/SQLClientSwift",
-            swiftSettings: [
-                .enableExperimentalFeature("StrictConcurrency=complete"),
-            ],
-            linkerSettings: [
-                .linkedLibrary("sybdb", .when(platforms: [.linux]))
-            ]
-        ),
-        .testTarget(
-            name: "SQLClientSwiftTests",
-            dependencies: ["SQLClientSwift"],
-            path: "Tests/SQLClientSwiftTests"
-        ),
-    ]
-)
+    targets: packageTargets
+)

Sources/CFreeTDS/include/CFreeTDS.h

@@ -1,9 +1,7 @@
-#ifndef CFREETDS_H
-#define CFREETDS_H
-
 #pragma once
 
+// Wrapper header for FreeTDS / libsybdb.
+// This module is only included in the package graph if sybdb.h is detected.
+
 #include <sybdb.h>
 #include <sybfront.h>
-
-#endif /* CFREETDS_H */