delimiter-precedes-last="never" is not respected for single field authors

[StianOby]

See this thread for examples, and in particular adamsmith's comment identifying the root cause (single field authors):
https://forums.zotero.org/discussion/129620/serial-comma-for-treaty-only-csl-or-zotero-bug

(This is apparently not an issue confined to the treaty type as I speculate in the forum thread, but a universal issue with single field authors.)

[zepinglee]

This is related to CSL-M's <institution> extension. The citeproc-js processor automatically adds an <institution> element into <names>, but it only copies the delimiter and and attributes from <name> element. The delimiter-precedes-last attribute of <name> is not copied to the <institution>.

citeproc-js/src/xmljson.js

Lines 416 to 464 in c3a03eb

	CSL.XmlJSON.prototype.addInstitutionNodes = function(myjson) {
	//print("addInstitutionNodes()");
	var names, thenames, institution, theinstitution, name, thename, xml, pos, len;
	// The idea here is to map relevant attributes from name and nampart=family
	// to the "long" institution-part node, when and only when forcing insert
	// of the default node.
	if (myjson.name === "names") {
	// do stuff
	var attributes = {};
	var insertPos = -1;
	for (var i=0,ilen=myjson.children.length;i<ilen;i+=1) {
	if (myjson.children[i].name == "name") {
	for (var key in myjson.children[i].attrs) {
	attributes[key] = myjson.children[i].attrs[key];
	}
	attributes.delimiter = myjson.children[i].attrs.delimiter;
	attributes.and = myjson.children[i].attrs.and;
	insertPos = i;
	for (var k=0,klen=myjson.children[i].children.length;k<klen;k+=1) {
	if (myjson.children[i].children[k].attrs.name !== 'family') {
	continue;
	}
	for (var key in myjson.children[i].children[k].attrs) {
	attributes[key] = myjson.children[i].children[k].attrs[key];
	}
	}
	}
	if (myjson.children[i].name == "institution") {
	insertPos = -1;
	break;
	}
	}
	if (insertPos > -1) {
	var institution = this.nodeCopy(this.institution);
	for (var i=0,ilen = CSL.INSTITUTION_KEYS.length;i<ilen;i+=1) {
	var attrname = CSL.INSTITUTION_KEYS[i];
	if ("undefined" !== typeof attributes[attrname]) {
	institution.children[0].attrs[attrname] = attributes[attrname];
	}
	if (attributes.delimiter) {
	institution.attrs.delimiter = attributes.delimiter;
	}
	if (attributes.and) {
	institution.attrs.and = attributes.and;
	}
	}
	myjson.children = myjson.children.slice(0,insertPos+1).concat([institution]).concat(myjson.children.slice(insertPos+1));
	}
	}

The last delimiter in the output name list is configured by the <institution> element if the last one is a literal name (i.e., isInstitution is true). The finalJoin in the following code has a prefix ", ", which means the delimiter-precedes-last attribute of the <name> element has no effect here.

citeproc-js/src/util_names_join.js

Lines 94 to 98 in c3a03eb

	if (blobs[blobs.length - 1].isInstitution) {
	finalJoin = this.institution.and[singleOrMultiple];
	} else {
	finalJoin = this.name.and[singleOrMultiple];
	}

[StianOby]

I don't fully understand the comment above, but in case it matters I just wanted to clarify one thing: I'm using vanilla Zotero 8. (And thus not Juris-M).

[bwiernik]

@zepinglee does any fix come to mind for you?

@StianOby Zotero and Jurism use the same processor, which supports both base CSL and the CSL-m extension. @zepinglee is just sharing his investigation of the cause of the bug.