Null ValueTree error but ValueTree exists?

#1

I have a ValueTree (patch) with a subtree (named “KEYLOCK”). I’d like to change the property “DEFAULTLOCK” of “KEYLOCK” when a toggle button is pressed, but I’m failing an assertion when I try to do so: “Trying to add a property to a null ValueTree will fail.” The weird thing is that, as far as I can tell, all ValueTrees in question appear to exist!

The following code prints the correct value of the property “DEFAULTLOCK” (set elsewhere in the code), but when I try to set it here I get the jassert.

juce::Logger::writeToLog(patch.getChildWithName(patchName).getProperty("DEFAULTLOCK") ? "true" : "false");
patch.getChildWithName(patchName).setProperty("DEFAULTLOCK", defaultLockButton.getToggleState(), nullptr);

Any ideas for what might be going on? Thank you!

#2

has the parent value tree you tried to add the property to been made valid yet? you can validate a valueTree by giving it an identifier (juce::String / juce::Identifier) at construction

#3

As far as I can tell, the parent value tree is valid: it has other child valuetrees which work as expected elsewhere. It also works here to read properties, but for some reason isn’t working to set them here.

Thank you!

#4

The class might be a normal initialised ValueTree, but like @Mrugalla pointed out: a ValueTree is considered invalid when it was constructed from the default constructor.
When you created the parent ValueTree, make sure to give it a type name:

juce::ValueTree patch;              // <= invalid
juce::ValueTree patch ("");         // <= invalid
juce::ValueTree patch ("whatever"); // <= valid

You seem to be able to use an invalid ValueTree, but in some functions there is a check to warn you that the ValueTree might not do what you expect.

Hope that helps

#5

what daniel says.

also it could be that at some point of your code you actually replaced a valid vt with an invalid one accidently. that would explain why it seems that some stuff works

#6

I think I figured it out; I was initializing the child ValueTree with a juce::Identifier&, but the Identifier was going out of scope before the ValueTree was accessed. Switching this to an object instead of a reference so that it made a copy of the original Identifier fixed this.

Thank you very much for the help!