is<T>() returns wrong value, only with bool

[marvinroger]

I am using an ESP8266 (NodeMCU 1.0) with the following sketch:

#include <ArduinoJson.h>

const char* json = "{\"ota\": {\"enabled\": true}}";

void setup() {
  Serial.begin(115200);
  Serial.println();

  StaticJsonBuffer<JSON_OBJECT_SIZE(1) + JSON_OBJECT_SIZE(1)> jsonBuffer;
  JsonObject& parsedJson = jsonBuffer.parseObject(json);
  if (parsedJson["ota"]["enabled"].is<bool>()) {
    Serial.println("ota.enabled is a bool");
  } else {
    Serial.println("ota.enabled is not a bool");
  }
}

void loop() {
  delay(1000);
}

This prints ota.enabled is not a bool, but it obviously is.
Note I tested with const char*, unsigned long, JsonObject& and it works well, the problem only appears with bool.

[bblanchon]

The bug is real, but the code sample is wrong.
The StaticJsonBuffer is too small to hold a copy of the input.
Remember: JsonBuffer will have to make a copy if the input is not mutable, ie if it's a const char* or a String.

Here is the fixed code:

#include <ArduinoJson.h>

char json[] = "{\"ota\": {\"enabled\": true}}";

void setup() {
  Serial.begin(115200);
  Serial.println();

  StaticJsonBuffer<JSON_OBJECT_SIZE(1) + JSON_OBJECT_SIZE(1)> jsonBuffer;
  JsonObject& parsedJson = jsonBuffer.parseObject(json);
  if (parsedJson["ota"]["enabled"].is<bool>()) {
    Serial.println("ota.enabled is a bool");
  } else {
    Serial.println("ota.enabled is not a bool");
  }
}

void loop() {
  delay(1000);
}

[marvinroger]

Right, my C++ background is a bit limited! But in my code I'm actually using mutable strings.

[bblanchon]

I fixed the bug, I just need to merge and make a new release

[marvinroger]

Great, thanks for the quick fix.

[bblanchon]

Fix in version 5.0.8