What causes "Can't check permissions for null context" in didi/DoKit?

Pass a non-null Context — ideally getApplicationContext() captured at init, or getActivity() guarded for null.

didi/DoKit · error · IllegalArgumentException

Can't check permissions for null context

Error message

Can't check permissions for null context

What it means

DoKitPermissionUtil.hasPermissions(context, perms...) returns true unconditionally below API 23 (the OS handles install-time permissions), so a null Context can only reach the real check on M+ devices — where it throws IllegalArgumentException('Can't check permissions for null context') before calling ContextCompat.checkSelfPermission. The library treats a null context on M+ as a programming error, since permission state fundamentally cannot be queried without one.

Source

Thrown at Android/dokit/src/main/java/com/didichuxing/doraemonkit/util/DoKitPermissionUtil.java:147

     *
     * @param context
     * @param perms
     * @return
     */
    public static boolean hasPermissions(@NonNull Context context,
                                         @Size(min = 1) @NonNull String... perms) {
        // Always return true for SDK < M, let the system deal with the permissions
        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M) {
            Log.w(TAG, "hasPermissions: API version < M, returning true by default");

            // DANGER ZONE!!! Changing this will break the library.
            return true;
        }

        // Null context may be passed if we have detected Low API (less than M) so getting
        // to this point with a null context should not be possible.
        if (context == null) {
            throw new IllegalArgumentException("Can't check permissions for null context");
        }

        for (String perm : perms) {
            if (ContextCompat.checkSelfPermission(context, perm)
                    != PackageManager.PERMISSION_GRANTED) {
                return false;
            }
        }

        return true;
    }

    /**
     * 检测是否有sd卡读写权限，不可靠。无sd卡或者磁盘满了的情况下，即使赋予了权限也可能报无权限
     *
     * @return
     */
    public static boolean checkStorageUnreliable() {

View on GitHub (pinned to 626827cddb)

Solutions

Pass a non-null Context — ideally getApplicationContext() captured at init, or getActivity() guarded for null.
In fragments, guard: Context ctx = getContext(); if (ctx == null) return; before permission checks.
Initialize any context field in onCreate/attach before the first hasPermissions call.
Note the varargs must also be non-empty (@Size(min = 1)); pass at least one permission.

Example fix

// before
if (DoKitPermissionUtil.hasPermissions(null, Manifest.permission.WRITE_EXTERNAL_STORAGE)) { ... }

// after
Context ctx = fragment.getContext();
if (ctx != null && DoKitPermissionUtil.hasPermissions(ctx, Manifest.permission.WRITE_EXTERNAL_STORAGE)) { ... }

Defensive patterns

Strategy: type-guard

Validate before calling

if (context != null) {
    boolean ok = DoKitPermissionUtil.hasPermissions(context, perms);
} else {
    // capture a context before permission checks
}

Type guard

static boolean canCheckPermissions(Context ctx) {
    return ctx != null && Build.VERSION.SDK_INT >= Build.VERSION_CODES.M;
}

Try / catch

Not recommended — IllegalArgumentException marks a caller bug; supply a real Context instead of catching.

Prevention

Capture getApplicationContext() at module init and use it for permission checks.
Guard fragment calls with getContext() null-checks (detached fragments return null).
Remember the <M path returns true by default, so tests must include API 23+ devices.

When it happens

Trigger: Calling DoKitPermissionUtil.hasPermissions(null, Manifest.permission.X) (or a wrapper that forwards a null Activity/Context) on a device running API 23+; a field-based context used before initialization; a detached fragment whose getActivity() returned null and was passed unchecked.

Common situations: Calling permission helpers from background services or broadcast receivers where a context was never captured; helper classes with a lazily-set application context that is null at first use; testing on old emulators (< M) masking the bug, then crashing on modern devices.

Related errors

AI-assisted analysis of didi/DoKit@626827cddb (2026-08-14). Data as JSON: /api/errors/83acb285ccebdd4c. Report an issue: GitHub.