feat(native): offline caching

The native daemon uses the same HTTP transport, so it gets offline
caching for free as long as the cache_keep option is propagated via
shared memory. Also, disable http_retry in the daemon since it is a
single-shot process where retry backoff makes no sense.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: jpnurmi

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+**Features**:
+
+- Add offline caching support to the new experimental `native` backend. ([#1585](https://github.com/getsentry/sentry-native/pull/1585))
+
 **Fixes**:
 
 - Fix `cache_keep` to only cache envelopes when HTTP send fails, instead of unconditionally on restart. ([#1585](https://github.com/getsentry/sentry-native/pull/1585))

src/backends/native/sentry_crash_context.h

@@ -260,6 +260,7 @@ typedef struct {
     int crash_reporting_mode; // sentry_crash_reporting_mode_t
     bool debug_enabled; // Debug logging enabled in parent process
     bool attach_screenshot; // Screenshot attachment enabled in parent process
+    bool cache_keep;
 
     // Platform-specific crash context
 #if defined(SENTRY_PLATFORM_LINUX) || defined(SENTRY_PLATFORM_ANDROID)

src/backends/native/sentry_crash_daemon.c

@@ -2966,6 +2966,7 @@ sentry__crash_daemon_main(pid_t app_pid, uint64_t app_tid, HANDLE event_handle,
     // Use debug logging and screenshot settings from parent process
     sentry_options_set_debug(options, ipc->shmem->debug_enabled);
     options->attach_screenshot = ipc->shmem->attach_screenshot;
+    options->cache_keep = ipc->shmem->cache_keep;
 
     // Set custom logger that writes to file
     if (log_file) {

src/backends/sentry_backend_native.c

@@ -176,6 +176,7 @@ native_backend_startup(
     // Pass debug logging setting to daemon
     ctx->debug_enabled = options->debug;
     ctx->attach_screenshot = options->attach_screenshot;
+    ctx->cache_keep = options->cache_keep;
 
     // Set up event and breadcrumb paths
     sentry_path_t *run_path = options->run->run_path;

tests/assertions.py

@@ -559,11 +559,12 @@ def assert_failed_proxy_auth_request(stdout):
 
 
 def wait_for_file(path, timeout=10.0, poll_interval=0.1):
+    import glob
     import time
 
     deadline = time.time() + timeout
     while time.time() < deadline:
-        if path.exists():
+        if glob.glob(str(path)):
             return True
         time.sleep(poll_interval)
     return False

tests/test_integration_native.py

@@ -19,6 +19,7 @@
 from .assertions import (
     assert_meta,
     assert_session,
+    wait_for_file,
 )
 from .conditions import has_native, is_kcov, is_asan
 
@@ -626,3 +627,30 @@ def test_crash_mode_native_with_minidump(cmake, httpserver):
 
     # Should have debug_meta
     assert "debug_meta" in event
+
+
+@pytest.mark.parametrize("cache_keep", [True, False])
+def test_native_cache_keep(cmake, cache_keep):
+    tmp_path = cmake(["sentry_example"], {"SENTRY_BACKEND": "native"})
+    db_dir = tmp_path / ".sentry-native"
+    cache_dir = db_dir / "cache"
+    unreachable_dsn = "http://uiaeosnrtdy@127.0.0.1:19999/123456"
+    env = dict(os.environ, SENTRY_DSN=unreachable_dsn)
+
+    # crash -> daemon sends via HTTP -> unreachable -> cache
+    run_crash(
+        tmp_path,
+        "sentry_example",
+        ["log", "stdout", "crash"] + (["cache-keep"] if cache_keep else []),
+        env=env,
+    )
+
+    if cache_keep:
+        assert wait_for_file(cache_dir / "*.envelope")
+        assert len(list(cache_dir.glob("*.envelope"))) == 1
+    else:
+        # Best-effort wait for crash processing to finish. 2s is not
+        # guaranteed to be enough, but we cannot poll for the non-existence
+        # of a file.
+        time.sleep(2)
+        assert len(list(cache_dir.glob("*.envelope"))) == 0