feat: add Windows and Linux support

.changeset/desktop-dart-sdk.md

@@ -0,0 +1,5 @@
+---
+"posthog_flutter": minor
+---
+
+Add Windows and Linux support, set up with the same `Posthog().setup(config)` as the other platforms. Event and screen capture, exception capture (including autocapture of Flutter and Dart errors, and exception steps), identify, alias, groups, super properties, feature flags, bootstrap, opt-out and application lifecycle events work on both. App metadata comes from the executable's `ProductName` and `ProductVersion` on Windows and the bundled `version.json` on Linux. State is stored under `posthog/<project token>` in the application support directory returned by the official Windows/Linux `path_provider` implementations. If the directory is unavailable, state stays in memory and is lost when the SDK closes or the app exits. Events include `$timezone` when the SDK can determine a local IANA time zone; on Windows, this uses the system ICU data on a best-effort basis. Session replay, surveys, logs, push notifications and native crash capture are not supported on Windows and Linux.

.github/workflows/ci.yml

@@ -174,7 +174,7 @@ jobs:
         if: needs.detect-markdown-only.outputs.markdown_only != 'true'
         timeout-minutes: 5
         working-directory: ./posthog_flutter
-        run: flutter test --platform chrome test/posthog_flutter_web_handler_test.dart test/posthog_flutter_web_setup_test.dart test/posthog_widget_web_test.dart test/posthog_widget_test.dart test/web_before_send_test.dart test/web_canvas_mask_provider_test.dart
+        run: flutter test --platform chrome test/posthog_flutter_web_handler_test.dart test/posthog_flutter_web_setup_test.dart test/posthog_widget_web_test.dart test/posthog_widget_test.dart test/web_before_send_test.dart test/web_canvas_mask_provider_test.dart test/posthog_error_tracking_web_test.dart
 
       # dart2js resolves the isolate-handler conditional import differently;
       # only a wasm compile exercises the dart2wasm selection this test guards.
@@ -184,6 +184,97 @@ jobs:
         working-directory: ./posthog_flutter
         run: flutter test --platform chrome --wasm test/posthog_isolate_error_handler_web_test.dart
 
+  test-build-windows:
+    needs: detect-markdown-only
+    name: Windows test and build
+    runs-on: windows-latest
+    timeout-minutes: 20
+    steps:
+      - name: Complete markdown-only PR check
+        if: needs.detect-markdown-only.outputs.markdown_only == 'true'
+        run: echo "Only Markdown files changed; no additional work is required for this check."
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        if: needs.detect-markdown-only.outputs.markdown_only != 'true'
+
+      # axi92/flutter-action is a fork of subosito/flutter-action that SHA-pins its internal
+      # actions/cache calls; subosito itself uses tag refs which conflicts with our org-wide
+      # "Require actions to be pinned to a full-length commit SHA" policy. Tracks upstream.
+      - uses: axi92/flutter-action@36d2c2625bac6ea011cd7808d2a01bd8a7e5c766 # feature/pin-action-sha @ 2026-04-30
+        if: needs.detect-markdown-only.outputs.markdown_only != 'true'
+        with:
+          channel: 'stable'
+          cache: true
+
+      - name: Install dependencies
+        if: needs.detect-markdown-only.outputs.markdown_only != 'true'
+        run: flutter pub get
+
+      - name: Test on Windows
+        if: needs.detect-markdown-only.outputs.markdown_only != 'true'
+        working-directory: ./posthog_flutter
+        run: flutter test
+
+      - name: Build Windows example
+        if: needs.detect-markdown-only.outputs.markdown_only != 'true'
+        working-directory: ./example
+        run: flutter build windows --release --build-name=1.2.3 --build-number=456
+
+      - name: Test Windows version resource
+        if: needs.detect-markdown-only.outputs.markdown_only != 'true'
+        working-directory: ./posthog_flutter
+        run: flutter test --dart-define=POSTHOG_TEST_EXECUTABLE=../example/build/windows/x64/runner/Release/posthog_flutter_example.exe test/posthog_windows_version_resource_test.dart
+
+      - name: Integration test on Windows
+        if: needs.detect-markdown-only.outputs.markdown_only != 'true'
+        working-directory: ./example
+        run: flutter test integration_test/desktop_test.dart -d windows
+
+  test-build-linux:
+    needs: detect-markdown-only
+    name: Linux test and build
+    runs-on: ubuntu-latest
+    timeout-minutes: 20
+    steps:
+      - name: Complete markdown-only PR check
+        if: needs.detect-markdown-only.outputs.markdown_only == 'true'
+        run: echo "Only Markdown files changed; no additional work is required for this check."
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        if: needs.detect-markdown-only.outputs.markdown_only != 'true'
+
+      - name: Install Linux build dependencies
+        if: needs.detect-markdown-only.outputs.markdown_only != 'true'
+        run: |
+          sudo apt-get update -y
+          sudo apt-get install -y clang cmake ninja-build pkg-config libgtk-3-dev libstdc++-12-dev
+
+      # axi92/flutter-action is a fork of subosito/flutter-action that SHA-pins its internal
+      # actions/cache calls; subosito itself uses tag refs which conflicts with our org-wide
+      # "Require actions to be pinned to a full-length commit SHA" policy. Tracks upstream.
+      - uses: axi92/flutter-action@36d2c2625bac6ea011cd7808d2a01bd8a7e5c766 # feature/pin-action-sha @ 2026-04-30
+        if: needs.detect-markdown-only.outputs.markdown_only != 'true'
+        with:
+          channel: 'stable'
+          cache: true
+
+      - name: Install dependencies
+        if: needs.detect-markdown-only.outputs.markdown_only != 'true'
+        run: flutter pub get
+
+      - name: Test on Linux
+        if: needs.detect-markdown-only.outputs.markdown_only != 'true'
+        working-directory: ./posthog_flutter
+        run: flutter test
+
+      - name: Build Linux example
+        if: needs.detect-markdown-only.outputs.markdown_only != 'true'
+        working-directory: ./example
+        run: flutter build linux --release
+
+      - name: Integration test on Linux
+        if: needs.detect-markdown-only.outputs.markdown_only != 'true'
+        working-directory: ./example
+        run: xvfb-run -a flutter test integration_test/desktop_test.dart -d linux
+
   publish-dry-run:
     needs: detect-markdown-only
     name: Pub publish dry run

LICENSE

@@ -46,3 +46,27 @@ AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.
+
+---
+
+The desktop core in posthog_flutter/lib/src/core is derived from PostHog/posthog-js-lite (posthog-core).
+
+Copyright (c) 2022 PostHog (part of Hiberly Inc)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

@@ -6,6 +6,32 @@ Please see the main [PostHog docs](https://posthog.com/docs).
 
 Specifically, the [Flutter docs](https://posthog.com/docs/libraries/flutter) details.
 
+## Desktop support
+
+Windows and Linux support the core analytics SDK. Session replay, surveys,
+logs, push notifications, and native crash capture are not supported.
+
+Desktop state is stored under `posthog/<project token>` in the application
+support directory returned by Flutter's Windows/Linux `path_provider`
+implementations. Keep the application's storage identity stable across releases:
+Windows uses the company/product metadata, and Linux uses the application ID,
+with executable-name fallbacks when that metadata is unavailable. On Linux,
+`path_provider` also reuses an existing executable-name directory if the
+application-ID directory does not exist.
+
+Await `Posthog().setup(config)` to finish initialization. If the application
+support directory is unavailable, desktop state stays in memory and is lost
+when the SDK closes or the app exits. If an I/O error prevents reading an
+existing state file, that client keeps state changes in memory and leaves the
+file untouched. A new client can try reading the file again. Corrupt file
+contents reset the state to defaults; the next state write replaces the file.
+
+`Posthog().close()` makes one attempt to send the queued events and waits for it
+for up to two seconds. Events it could not send stay on disk and go out with the
+next client, or are lost when state is kept in memory. Closing the app window
+does not call `close()`, but the SDK also sends the queue whenever the app
+becomes inactive.
+
 ## Questions?
 
 ### [Check out our community page.](https://posthog.com/posts)

api/posthog_flutter.api.json

@@ -68,6 +68,36 @@
         ],
         "fieldDeclarations": [],
         "interfaceDeclarations": [
+            {
+                "entryPoints": [
+                    "posthog_flutter_dart.dart"
+                ],
+                "executableDeclarations": [
+                    {
+                        "entryPoints": [],
+                        "isDeprecated": false,
+                        "isExperimental": false,
+                        "isStatic": true,
+                        "name": "registerWith",
+                        "parameters": [],
+                        "relativePath": "lib/posthog_flutter_dart.dart",
+                        "returnTypeName": "void",
+                        "type": "method",
+                        "typeParameterNames": []
+                    }
+                ],
+                "fieldDeclarations": [],
+                "isDeprecated": false,
+                "isExperimental": false,
+                "isRequired": false,
+                "isSealed": false,
+                "name": "PosthogFlutterDart",
+                "relativePath": "lib/posthog_flutter_dart.dart",
+                "superTypeNames": [
+                    "Object"
+                ],
+                "typeParameterNames": []
+            },
             {
                 "entryPoints": [
                     "posthog_flutter_web.dart"
@@ -5952,6 +5982,18 @@
         "iosPlatformConstraints": null,
         "minSdkVersion": "3.6.0",
         "packageDependencies": [
+            {
+                "packageName": "path_provider_linux",
+                "packageVersion": "^2.2.1"
+            },
+            {
+                "packageName": "path_provider_platform_interface",
+                "packageVersion": "^2.1.2"
+            },
+            {
+                "packageName": "path_provider_windows",
+                "packageVersion": "^2.3.0"
+            },
             {
                 "packageName": "plugin_platform_interface",
                 "packageVersion": "^2.0.2"

example/.metadata

@@ -18,6 +18,12 @@ migration:
     - platform: macos
       create_revision: 78666c8dc57e9f7548ca9f8dd0740fbf0c658dc9
       base_revision: 78666c8dc57e9f7548ca9f8dd0740fbf0c658dc9
+    - platform: windows
+      create_revision: 78666c8dc57e9f7548ca9f8dd0740fbf0c658dc9
+      base_revision: 78666c8dc57e9f7548ca9f8dd0740fbf0c658dc9
+    - platform: linux
+      create_revision: 4cf24164269a5ebf0c16a028a00727d0e77bbb05
+      base_revision: 4cf24164269a5ebf0c16a028a00727d0e77bbb05
 
   # User provided section