toml: fix silent failure on meta-key insertion

fixes ElektraInitiative#4579

doc/decisions/0_drafts/readonly_keynames.md

@@ -0,0 +1,86 @@
+# Readonly Keynames
+
+## Problem
+
+It might be a good idea to prevent changes to the keyname after creation.
+Currently, the name of a key is automatically made read-only, when it is currently part of or at some point in the past was part of at least one `KeySet`.
+There are discussions about making key names writable again, when the key is removed from all `KeySet`s.
+
+There may also be situations where changing the name of a key after its creation is required.
+In some situations, it may be wise to reuse a key instead of deleting it and creating a new one.
+
+## Constraints
+
+1. `keyAddName` et al. still have to work up to a certain point
+2.
+3.
+
+## Assumptions
+
+1.
+2.
+3.
+
+## Considered Alternatives
+
+### Separate API for keynames
+
+Use the proposed `ElektraBuffer` struct to create a separate API for keynames independent of the `Key` API.
+
+### Read-only keynames
+
+The key name should be permanently read-only after creation.
+
+TBD: How would we dynamically create keynames with this approach?
+
+### Re-entrant lock for the key name
+
+Since we assume a single threaded context, this can be implemented as a simple counter.
+
+```c
+struct _Key {
+    // [...] other stuff
+   uint16_t nameLock; // if zero, name is writable, otherwise name is readonly
+};
+
+void keyLockName (Key * k) {
+    k->nameLock++;
+}
+
+void keyUnlockName (Key * k) {
+    if (k->nameLock == 0) return;
+    k->nameLock--;
+}
+
+void ksAppendKey (KeySet * ks, Key * k) {
+    keyLockName (k);
+    // [...]
+}
+
+void ksRemove (KeySet * ks, elektraCursor cursor) {
+    keyUnlockName (ks->array[cursor]);
+    // [...]
+}
+```
+
+### Alternative C
+
+## Decision
+
+## Rationale
+
+## Implications
+
+-
+-
+-
+
+## Related Decisions
+
+- []()
+- []()
+- []()
+
+## Notes
+
+- [Issue 2202](https://issues.libelektra.org/2202) talks about how unexpected it is that keys will be readonly once in a keyset, but they don't get unlocked when removing them from a keyset.

doc/news/_preparation_next_release.md

@@ -97,6 +97,12 @@ The following text lists news about the [plugins](https://www.libelektra.org/plu
 - Fix redirect logic to not cause loops _(@stefnotch)_
 - <<TODO>>
 
+### toml
+
+- Fix bug, where meta-keys that cannot be inserted don't report an error _(@Bujuhu)_
+- <<TODO>>
+- <<TODO>>
+
 ### uname
 
 - Add error handling if uname call fails _(Richard Stöckl @Eiskasten)_
@@ -355,7 +361,7 @@ This section keeps you up-to-date with the multi-language support provided by El
 - <<TODO>>
 - Many small fixes to adapt to documentation guidelines and new decision process. _(Markus Raab)_
 - <<TODO>>
-- <<TODO>>
+- Add decision for [read-only keynames](../decisions/0_drafts/readonly_keynames.md) _(Maximilian Irlinger @atmaxinger)_
 - <<TODO>>
 - <<TODO>>
 - <<TODO>>

src/plugins/toml/testmod_toml.c

@@ -145,6 +145,7 @@ static const char * prefix = NULL;
 		if (lastKey != NULL) keySetMeta (lastKey, "binary", NULL);                                                                 \
 	}
 
+static bool writeFile (const char * filename, KeySet * ksWrite, int pluginStatus);
 static void testRoundtrip (const char * filePath);
 static void testRead (void);
 static void testReadRoot (void);
@@ -176,6 +177,7 @@ static void testWriteReadComments (void);
 static void testWriteReadCommentsArray (void);
 static void testWriteReadOrderTableNonTable (void);
 static void testWriteReadNull (void);
+static void testWriteReadBogusMetaMustError(void);
 // static void testWriteReadBase64(void);
 static Key * addKey (KeySet * ks, const char * name, const char * value, size_t size, const char * orig, const char * type,
 		     const char * array, const char * tomltype, int order);
@@ -341,6 +343,7 @@ static void testWriteRead (const char * _prefix)
 	testWriteReadInlineTableInArray ();
 	testWriteReadArrayInlineTableAlternating ();
 	testWriteReadOrderTableNonTable ();
+	testWriteReadBogusMetaMustError();
 	prefix = NULL;
 }
 
@@ -457,6 +460,18 @@ static void testWriteReadNull (void)
 	TEST_WR_FOOT;
 }
 
+static void testWriteReadBogusMetaMustError (void)
+{
+	TEST_WR_HEAD;                                                                                            \
+	WRITE_KEY ("asdf");
+	SET_META("asdf", "asdf");
+	writeFile("test_write_read.toml", writeKs, ELEKTRA_PLUGIN_STATUS_ERROR);
+	keyDel (lastKey);   
+	ksDel (expectedKs);                                                                                                                \
+	ksDel (writeKs);                                                                                                           \
+	printf ("End Test: %s\n\n", __func__);                                                                        \
+}
+
 /*static void testWriteReadBase64 (void)
 {
 	TEST_WR_HEAD;
@@ -1423,7 +1438,7 @@ static KeySet * readFile (const char * filename)
 	return ks;
 }
 
-static bool writeFile (const char * filename, KeySet * ksWrite)
+static bool writeFile (const char * filename, KeySet * ksWrite, int pluginStatus)
 {
 	bool success = true;
 	ELEKTRA_LOG_DEBUG ("Writing '%s'\n", filename);
@@ -1433,8 +1448,8 @@ static bool writeFile (const char * filename, KeySet * ksWrite)
 	PLUGIN_OPEN ("toml");
 
 	int setStatus = plugin->kdbSet (plugin, ksWrite, parentKey);
-	succeed_if (setStatus == ELEKTRA_PLUGIN_STATUS_SUCCESS, "Could not write keys");
-	if (setStatus != ELEKTRA_PLUGIN_STATUS_SUCCESS)
+	succeed_if (setStatus == pluginStatus, "Writing keys did not return with expected Status");
+	if (setStatus != pluginStatus)
 	{
 		output_error (parentKey);
 		success = false;
@@ -1448,7 +1463,7 @@ static void testWriteReadCompare (KeySet * ksWrite, KeySet * expected)
 {
 	const char * filename = "test_write_read.toml";
 
-	if (writeFile (filename, ksWrite))
+	if (writeFile (filename, ksWrite, ELEKTRA_PLUGIN_STATUS_SUCCESS))
 	{
 		{
 			KeySet * ksRead = readFile (filename);
@@ -1469,7 +1484,7 @@ static bool roundtripFile (const char * filenameIn, const char * filenameOut)
 	{
 		return false;
 	}
-	bool success = writeFile (filenameOut, ksRead);
+	bool success = writeFile (filenameOut, ksRead, ELEKTRA_PLUGIN_STATUS_SUCCESS);
 	ksDel (ksRead);
 	return success;
 }

src/plugins/toml/write.c

@@ -858,6 +858,15 @@ static int collectComments (CommentList ** comments, Key * key, Writer * writer)
 				subDepth++;
 				pos += elektraStrLen (pos);
 			}
+		//Accept valid metakeys, throw error for everything else
+		} else if(elektraStrCmp(pos, "order") != 0 && 
+			elektraStrCmp(pos, "type") != 0 && 
+			elektraStrCmp(pos, "tomltype") != 0 && 
+			elektraStrCmp(pos, "origvalue") != 0 &&
+			elektraStrCmp(pos, "binary") != 0 &&
+			elektraStrCmp(pos, "array") != 0) {
+			ELEKTRA_SET_RESOURCE_ERRORF(key, "The Metakey %s is not supported by TOML", keyString(meta));
+			return -1;
 		}
 	}
 	*comments = commentRoot;