Limit the number of owners per project

src/templates/src/project_edit.html

@@ -236,6 +236,8 @@
 	const OWNER_QUERY_STATE_IDLE = 0;
 	const OWNER_QUERY_STATE_QUERYING = 1;
 
+	const MAX_OWNERS = {{ .MaxOwners }};
+
 	let ownerCheckUrl = "{{ .APICheckUsernameUrl }}";
 	let ownerQueryState = OWNER_QUERY_STATE_IDLE;
 	let addOwnerInput = document.querySelector("#owner_name");
@@ -256,6 +258,12 @@
 		startAddOwner();
 	});
 
+	function updateAddOwnerStyles() {
+		const numOwnerRows = document.querySelectorAll('.owner_row').length;
+		addOwnerInput.disabled = numOwnerRows >= MAX_OWNERS;
+	}
+	updateAddOwnerStyles();
+
 	function startAddOwner() {
 		if (ownerQueryState == OWNER_QUERY_STATE_QUERYING) {
 			return;
@@ -310,6 +318,7 @@
 		querying = (ownerQueryState == OWNER_QUERY_STATE_QUERYING);
 		addOwnerInput.disabled = querying;
 		addOwnerButton.disabled = querying;
+		updateAddOwnerStyles();
 	}
 
 	function addOwner(username) {
@@ -317,12 +326,14 @@
 		ownerEl.input.value = username;
 		ownerEl.name.textContent = username;
 		ownerList.appendChild(ownerEl.root);
+		updateAddOwnerStyles();
 	}
 
 	ownerList.addEventListener("click", function(ev) {
 		if (ev.target.classList.contains("remove_owner")) {
 			ev.target.parentElement.remove();
 		}
+		updateAddOwnerStyles();
 	});
 
 	/////////////////////

src/website/projects.go

@@ -27,6 +27,7 @@ import (
 )
 
 const maxPersonalProjects = 5
+const maxProjectOwners = 5
 
 type ProjectTemplateData struct {
 	templates.BaseData
@@ -383,6 +384,7 @@ type ProjectEditData struct {
 
 	Editing         bool
 	ProjectSettings templates.ProjectSettings
+	MaxOwners       int
 
 	APICheckUsernameUrl string
 	LogoMaxFileSize     int
@@ -408,6 +410,7 @@ func ProjectNew(c *RequestContext) ResponseData {
 		BaseData:        getBaseDataAutocrumb(c, "New Project"),
 		Editing:         false,
 		ProjectSettings: project,
+		MaxOwners:       maxProjectOwners,
 
 		APICheckUsernameUrl: hmnurl.BuildAPICheckUsername(),
 		LogoMaxFileSize:     ProjectLogoMaxFileSize,
@@ -508,6 +511,7 @@ func ProjectEdit(c *RequestContext) ResponseData {
 		BaseData:        getBaseDataAutocrumb(c, "Edit Project"),
 		Editing:         true,
 		ProjectSettings: projectSettings,
+		MaxOwners:       maxProjectOwners,
 
 		APICheckUsernameUrl: hmnurl.BuildAPICheckUsername(),
 		LogoMaxFileSize:     ProjectLogoMaxFileSize,
@@ -629,6 +633,10 @@ func ParseProjectEditForm(c *RequestContext) ProjectEditFormResult {
 	}
 
 	owners := c.Req.Form["owners"]
+	if len(owners) > maxProjectOwners {
+		res.RejectionReason = fmt.Sprintf("Projects can have at most %d owners", maxProjectOwners)
+		return res
+	}
 
 	slug := strings.TrimSpace(c.Req.Form.Get("slug"))
 	officialStr := c.Req.Form.Get("official")