Fixed M117 "string too long" issue

4 files changed, 5 insertions, 4 deletions

diff --git a/src/Configuration.h b/src/Configuration.h
index 32344a03..dd67344f 100644
--- a/src/Configuration.h
+++ b/src/Configuration.h
@@ -237,7 +237,7 @@ constexpr size_t GCodeReplyLength = StringLength256;	// Maximum number of charac
 constexpr size_t MachineNameLength = StringLength50;
 constexpr size_t RepRapPasswordLength = StringLength20;
 constexpr size_t MediumStringLength = MaxFilenameLength;
-constexpr size_t StringBufferLength = StringLength256;	// Length of the string buffer used by the expression parser
+constexpr size_t M117StringLength = MediumStringLength;
 constexpr size_t StringLengthLoggedCommand = StringLength100;	// Length of a string buffer for a command to be logged
 
 #if SAM4E || SAM4S || SAME70 || SAME5x || defined(ESP_NETWORKING)
diff --git a/src/GCodes/GCodeBuffer/StringParser.cpp b/src/GCodes/GCodeBuffer/StringParser.cpp
index 8b4df0f0..4c89a853 100644
--- a/src/GCodes/GCodeBuffer/StringParser.cpp
+++ b/src/GCodes/GCodeBuffer/StringParser.cpp
@@ -1278,7 +1278,7 @@ void StringParser::InternalGetQuotedString(const StringRef& str) THROWS(GCodeExc
 			}
 			else if (gb.buffer[readPointer] == c)
 			{
-				// Two backslashes are used to represent one
+				// Two single quote characters are used to represent one
 				++readPointer;
 			}
 		}
diff --git a/src/GCodes/GCodeQueue.cpp b/src/GCodes/GCodeQueue.cpp
index 300ca2b8..9412e735 100644
--- a/src/GCodes/GCodeQueue.cpp
+++ b/src/GCodes/GCodeQueue.cpp
@@ -71,7 +71,8 @@ GCodeQueue::GCodeQueue() noexcept : freeItems(nullptr), queuedItems(nullptr)
 				case 117:	// display message
 					{
 						// We need to call GetUnprecedentedString to ensure that if the string argument is not quoted, gb.DataLength() will return the correct value.
-						String<1> dummy;
+						// We need to pass the correct length string buffer here because GetUnprecedentedString will throw if the string is too long for the buffer.
+						String<M117StringLength> dummy;
 						gb.GetUnprecedentedString(dummy.GetRef());
 					}
 					return true;
diff --git a/src/GCodes/GCodes2.cpp b/src/GCodes/GCodes2.cpp
index ebca723f..cbe9497d 100644
--- a/src/GCodes/GCodes2.cpp
+++ b/src/GCodes/GCodes2.cpp
@@ -1767,7 +1767,7 @@ bool GCodes::HandleMcode(GCodeBuffer& gb, const StringRef& reply) THROWS(GCodeEx
 
 		case 117:	// Display message
 			{
-				String<MediumStringLength> msg;
+				String<M117StringLength> msg;
 				gb.GetUnprecedentedString(msg.GetRef(), true);
 				reprap.SetMessage(msg.c_str());
 			}