Add error handling for MDBX_MAP_FULL with descriptive error messages (#161)

* Add error handling for MDBX_MAP_FULL with descriptive error messages

* Allow cmake installation downgrade in GitHub Actions workflow setup.

---------

Co-authored-by: JkLondon <ilya@mikheev.fun>

Author: JkLondon

.github/workflows/test.yml

@@ -34,7 +34,7 @@ jobs:
       - name: Install dependencies
         run: |
           choco upgrade mingw -y --no-progress --version 13.2.0
-          choco install cmake -y --no-progress --version 3.27.8
+          choco install cmake -y --no-progress --version 3.27.8 --allow-downgrade
 
       - uses: actions/checkout@v4
       - uses: actions/setup-go@v5

mdbx/error.go

@@ -84,15 +84,19 @@ var CorruptErrorHardwareRecommendations = "Maybe free space is over on disk. Oth
 var CorruptErrorBacktraceRecommendations = "Otherwise - please create issue in Application repo." // with backtrace or coredump. To create coredump set compile option 'MDBX_FORCE_ASSERTIONS=1' and env variable 'GOTRACEBACK=crash'."
 var CorruptErrorRecoveryRecommendations = "On default DURABLE mode, power outage can't cause this error. On other modes - power outage may break last transaction and mdbx_chk can recover db in this case, see '-t' and '-0|1|2' options."
 var CorruptErrorMessage = CorruptErrorHardwareRecommendations + " " + CorruptErrorBacktraceRecommendations + " " + CorruptErrorRecoveryRecommendations
+var MapFullErrorMessage = "The allocated database storage size limit has been reached."
 
 func (e Errno) Error() string {
-	if e == Corrupted {
-		return "MDBX_FATAL: " + CorruptErrorMessage
+	switch e {
+	case Corrupted:
+		return fmt.Sprintf("MDBX_FATAL(%d): ", int(e)) + CorruptErrorMessage
+	case Panic:
+		return fmt.Sprintf("MDBX_PANIC(%d): ", int(e)) + CorruptErrorMessage
+	case MapFull:
+		return fmt.Sprintf("MDBX_MAP_FULL(%d)", int(e)) + MapFullErrorMessage
+	default:
+		return C.GoString(C.mdbx_strerror(C.int(e)))
 	}
-	if e == Panic {
-		return "MDBX_PANIC: " + CorruptErrorMessage
-	}
-	return C.GoString(C.mdbx_strerror(C.int(e)))
 }
 
 // _operrno is for use by tests that can't import C