fix: add CSQLite system library for Linux SQLite3 support

- Create Sources/CSQLite/module.modulemap for Linux sqlite3
- Add #if canImport(SQLite3) conditional imports in SQLiteNio sources
- Add #if os(Linux) CSQLite system library target in Package.swift
- Add libsqlite3-dev install step to all CI/release workflow jobs
- Fix PostgreSQL health-cmd to use pg_isready without -d flag

This fixes the root cause of all CI job failures: 'import SQLite3'
not resolving on Linux caused SwiftPM to fail compiling the entire
package, which broke SQLite, PostgreSQL, MySQL, and MSSQL test jobs.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: vkuttyp

.github/workflows/ci.yml

@@ -59,6 +59,10 @@ jobs:
           restore-keys: |
             ${{ runner.os }}-spm-${{ matrix.swift }}-
 
+      - name: Install SQLite (Linux)
+        if: runner.os == 'Linux'
+        run: sudo apt-get install -y libsqlite3-dev
+
       - name: Build
         run: swift build --configuration debug 2>&1
 
@@ -98,6 +102,9 @@ jobs:
         with:
           swift-version: ${{ env.SWIFT_VERSION }}
 
+      - name: Install SQLite
+        run: sudo apt-get install -y libsqlite3-dev
+
       - name: Cache SPM
         uses: actions/cache@v4
         with:
@@ -137,7 +144,7 @@ jobs:
         ports:
           - 5432:5432
         options: >-
-          --health-cmd "pg_isready -U pguser -d PostgresNioTestDb"
+          --health-cmd "pg_isready -U pguser"
           --health-interval 5s
           --health-timeout 3s
           --health-retries 10
@@ -150,6 +157,9 @@ jobs:
         with:
           swift-version: ${{ env.SWIFT_VERSION }}
 
+      - name: Install SQLite
+        run: sudo apt-get install -y libsqlite3-dev
+
       - name: Cache SPM
         uses: actions/cache@v4
         with:
@@ -196,6 +206,9 @@ jobs:
         with:
           swift-version: ${{ env.SWIFT_VERSION }}
 
+      - name: Install SQLite
+        run: sudo apt-get install -y libsqlite3-dev
+
       - name: Cache SPM
         uses: actions/cache@v4
         with:

.github/workflows/release.yml

@@ -21,6 +21,8 @@ jobs:
       - uses: swift-actions/setup-swift@v2
         with:
           swift-version: "6.0"
+      - name: Install SQLite
+        run: sudo apt-get install -y libsqlite3-dev
       - run: swift test --filter SQLiteNioTests
       - run: swift test --filter SQLNioCoreTests
 
@@ -44,6 +46,8 @@ jobs:
       - uses: swift-actions/setup-swift@v2
         with:
           swift-version: "6.0"
+      - name: Install SQLite
+        run: sudo apt-get install -y libsqlite3-dev
       - name: Run PostgreSQL tests
         env:
           PG_TEST_HOST: "127.0.0.1"
@@ -73,6 +77,8 @@ jobs:
       - uses: swift-actions/setup-swift@v2
         with:
           swift-version: "6.0"
+      - name: Install SQLite
+        run: sudo apt-get install -y libsqlite3-dev
       - name: Run MySQL tests
         env:
           MYSQL_TEST_HOST: "127.0.0.1"
@@ -101,6 +107,8 @@ jobs:
       - uses: swift-actions/setup-swift@v2
         with:
           swift-version: "6.0"
+      - name: Install SQLite
+        run: sudo apt-get install -y libsqlite3-dev
       - name: Create test database
         run: |
           until /opt/mssql-tools18/bin/sqlcmd -S 127.0.0.1 -U sa -P 'aBCD111!' -C \

Package.swift

@@ -1,6 +1,20 @@
 // swift-tools-version: 5.9
 import PackageDescription
 
+// SQLite is provided by the Apple SDK on Darwin; on Linux we need a system library.
+#if canImport(Darwin)
+let sqliteSystemLibTargets: [Target] = []
+let sqliteNioExtraDeps:       [Target.Dependency] = []
+let sqliteNioLinkerSettings:  [LinkerSetting] = [.linkedLibrary("sqlite3")]
+#else
+let sqliteSystemLibTargets: [Target] = [
+    .systemLibrary(name: "CSQLite", pkgConfig: "sqlite3",
+                   providers: [.apt(["libsqlite3-dev"])]),
+]
+let sqliteNioExtraDeps:       [Target.Dependency] = [.target(name: "CSQLite")]
+let sqliteNioLinkerSettings:  [LinkerSetting] = []
+#endif
+
 let package = Package(
     name: "sql-nio",
     platforms: [
@@ -86,9 +100,9 @@ let package = Package(
                 .product(name: "NIOCore",   package: "swift-nio"),
                 .product(name: "NIOPosix",  package: "swift-nio"),
                 .product(name: "Logging",   package: "swift-log"),
-            ],
+            ] + sqliteNioExtraDeps,
             swiftSettings: swiftSettings,
-            linkerSettings: [.linkedLibrary("sqlite3")]
+            linkerSettings: sqliteNioLinkerSettings
         ),
 
         // ── Tests ─────────────────────────────────────────────────────────────
@@ -130,7 +144,7 @@ let package = Package(
             ],
             swiftSettings: swiftSettings
         ),
-    ]
+    ] + sqliteSystemLibTargets
 )
 
 var swiftSettings: [SwiftSetting] { [

Sources/CSQLite/module.modulemap

@@ -0,0 +1,5 @@
+module CSQLite [system] {
+    header "sqlite3.h"
+    link "sqlite3"
+    export *
+}

Sources/SQLiteNio/SQLiteBackup.swift

@@ -1,4 +1,8 @@
+#if canImport(SQLite3)
 import SQLite3
+#else
+import CSQLite
+#endif
 import Foundation
 import NIOCore
 import SQLNioCore

Sources/SQLiteNio/SQLiteConnection.swift

@@ -1,4 +1,8 @@
+#if canImport(SQLite3)
 import SQLite3
+#else
+import CSQLite
+#endif
 import Foundation
 import NIOCore
 import NIOPosix