gistfile1.js

// Selects all text layers that have the same text style as the reference text layer (command control t)

// init

var layerCount = 0;
var pageCount = 0;
var lastFoundOnPage = -1;
var selectedLayers = [];
var i = 0;

// We can only search for similar text layers when a reference layer is selected

if (selection.count() == 1) {

	[doc showMessage: "Looking for similar text layers…"]

	// Remember the reference text style

	var reference = selection[0].style().textStyle().attributes();

	// Loop through pages
    var pages = doc.pages().objectEnumerator();
    while (page = pages.nextObject()) {
    	i++;
		// Loop through all children of the page
		var layers = page.children().objectEnumerator();
		while (layer = layers.nextObject()) {

			// Check if the layer is a text layer
	  		if ([layer isKindOfClass:MSTextLayer]) {
	  			if(layer.style().textStyle().attributes() == reference) {
	  				[layer select:true byExpandingSelection:true];
	  				layerCount++;
	  			  	if (i != lastFoundOnPage) {
	  			  		pageCount++;
	  			  		lastFoundOnPage = i;
	  			  	}
	  			}
	  		}
	}
}

	// Show how many layers have been selected
	[doc showMessage: layerCount + " layers on " + pageCount + " pages selected."]

} else {
	[doc showMessage: "Please select a single reference text layer."]
}

// Selects all text layers that have the same text style as the reference text layer (command control t)

// init

var pageCount = 0,
  layerCount = 0,
  textLayerCount = 0,
  selectedLayerCount = 0,
  lastFoundOnPage = -1,
  selectedLayers = [],
  i = 0,
  reference = null,
  pages,
  page,
  layers,
  layer;

// We can only search for similar text layers when a reference layer is selected

if (selection.count() === 1) {

  doc.showMessage("Looking for similar text layers…");

  // Remember the reference text style
  reference = selection[0].style().textStyle().attributes();

  // Loop through pages
  pages = doc.pages().objectEnumerator();

  while (page = pages.nextObject()) {
    i++;
    pageCount++;

    // Loop through all children of the page
    layers = page.children().objectEnumerator();

    while (layer = layers.nextObject()) {
      layerCount++;

      // Check if the layer is a text layer
      if (layer.isKindOfClass(MSTextLayer)) {
        textLayerCount++;

        if (layer.style().textStyle().attributes() === reference) {
          layer.setIsSelected(true);
          selectedLayerCount++;

          if (i !== lastFoundOnPage) {
            lastFoundOnPage = i;
          }
        }
      }
    }
  }

  // Show how many layers have been selected
  doc.showMessage(selectedLayerCount + " text layers selected within " +
    textLayerCount + " exisiting text layers within " +
    layerCount + " layers on " +
    pageCount + " pages.");
} else {
  doc.showMessage("Please select a single reference text layer.");
}

What I did:

• I rewrote all Cocoa code into the JavaScript equivalent
• I moved all variable definitions into the »init« section
• I changed week equality to strong equality (!= and == to !== and ===)
• I added semicolons to all lines where needed
• I added counters at more places to see if the script touches all layers
• I changed the layer selection code to layer.setIsSelected(true);

Only the last change is relevant, the other changes may be lint optimizations.

For me this changed script selects the layers as expected without crashes.