From: Miod Vallat <miod.vallat@powerdns.com>
Date: Thu, 19 Jun 2025 10:29:47 +0000 (+0200)
Subject: Make lmdb del() operations throw upon error.
X-Git-Tag: rec-5.3.0-alpha1~3^2~3
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=436f4284b6b4cdf305bf04ae792f27bf4d1aca99;p=thirdparty%2Fpdns.git

Make lmdb del() operations throw upon error.

In the current state of the code, in flag-deleted mode, failures always
throw; but in regular mode, in the unlikely event of an error during
deletion from cursor, the returned value would be either ignored or...
used to throw an exception.

Signed-off-by: Miod Vallat <miod.vallat@powerdns.com>
---

diff --git a/ext/lmdb-safe/lmdb-safe.hh b/ext/lmdb-safe/lmdb-safe.hh
index 07148ecb0d..d8b84f7900 100644
--- a/ext/lmdb-safe/lmdb-safe.hh
+++ b/ext/lmdb-safe/lmdb-safe.hh
@@ -824,7 +824,7 @@ public:
   }
 #endif
 
-  int del(MDBDbi& dbi, const MDBInVal& key)
+  void del(MDBDbi& dbi, const MDBInVal& key)
   {
     // NOLINTNEXTLINE(cppcoreguidelines-pro-type-cstyle-cast)
     int mdbDelRc = mdb_del(d_txn, dbi, (MDB_val*)&key.d_mdbval, nullptr);
@@ -855,7 +855,6 @@ public:
       }
     }
 #endif
-    return mdbDelRc;
   }
 
   int get(MDBDbi& dbi, const MDBInVal& key, MDBOutVal& val)
@@ -942,7 +941,7 @@ public:
 #endif
 
 #ifndef DNSDIST
-  int del(int flags=0)
+  void del(int flags=0)
   {
     MDBOutVal key, val;
 
@@ -950,7 +949,7 @@ public:
       int rc_get = mdb_cursor_get (*this, &key.d_mdbval, &val.d_mdbval, MDB_GET_CURRENT);
 
       if(rc_get) {
-              throw std::runtime_error("getting key to mark data as deleted: " + std::string(mdb_strerror(rc_get)));
+        throw std::runtime_error("getting key to mark data as deleted: " + std::string(mdb_strerror(rc_get)));
       }
 
       size_t txid = mdb_txn_id(d_txn);
@@ -966,15 +965,16 @@ public:
 
       int rc_put = mdb_cursor_put(*this,
                      const_cast<MDB_val*>(&pkey.d_mdbval),
-                     const_cast<MDB_val*>(&pval.d_mdbval), 0 /* MDB_CURRENT */);
+                     const_cast<MDB_val*>(&pval.d_mdbval), 0);
       if(rc_put) {
-              throw std::runtime_error("marking data deleted: " + std::string(mdb_strerror(rc_put)));
+        throw std::runtime_error("marking data deleted: " + std::string(mdb_strerror(rc_put)));
       }
-      return rc_put;
     }
     else {
       // do a normal delete
-      return mdb_cursor_del(*this, flags);
+      if (int rc_del = mdb_cursor_del(*this, flags); rc_del != 0) {
+        throw std::runtime_error("deleting data: " + std::string(mdb_strerror(rc_del)));
+      }
     }
   }
 #endif
diff --git a/ext/lmdb-safe/lmdb-typed.hh b/ext/lmdb-safe/lmdb-typed.hh
index 4cdcb4efaf..bf78f8253c 100644
--- a/ext/lmdb-safe/lmdb-typed.hh
+++ b/ext/lmdb-safe/lmdb-typed.hh
@@ -158,10 +158,7 @@ struct LMDBIndexOps
     auto scombined = makeCombinedKey(keyConv(d_parent->getMember(type)), idVal);
     MDBInVal combined(scombined);
 
-    int errCode = txn->del(d_idx, combined);
-    if (errCode != 0) {
-      throw std::runtime_error("Error deleting from index: " + std::string(mdb_strerror(errCode)));
-    }
+    txn->del(d_idx, combined);
   }
 
   void openDB(std::shared_ptr<MDBEnv>& env, string_view str, int flags)