GWT SuperDevMode throws this: Multiple fragment 0 sourcemaps found. Too many permutations - gwt

Question

I am using SuperDevMode with Chrome and it worked fine until suddently the sourcemaps stopped showing in Chrome.
And CodeServer throws the following exception: Multiple fragment 0 sourcemaps found. Too many permutations.
During compilation it shows:
Compiling 5 permutations
Compiling permutation 0...
Source Maps Enabled
Compiling permutation 1...
Source Maps Enabled
Compiling permutation 2...
Source Maps Enabled
Compiling permutation 3...
Source Maps Enabled
Compiling permutation 4...
Source Maps Enabled
Compile of permutations succeeded
Any ideas?

Answer 1

By default GWT compiles 6 basic permutations, one for each category of browser.
Firefox, all versions
All Webkit browsers (Safari, Chrome, Android Browser, etc)
IE6 and IE7
IE8
IE9 (and IE10)
Opera
There is a reported issue about that: Issue 7458: Super Dev Mode shouldn't compile 6 permutations when user.agent is missing
Suggested workaround from the issue description:
is to restrict the browser permutations in the gwt.xml file. For example, if you are using Chrome or Safari:
<set-property name="user.agent" value="safari"/>
Also if you're using Sencha GXT I also recommend look through the following article: Using the GWT Compiler for Better Builds
According to the article I also added following line to my gwt.xml:
<collapse-all-properties />
So finaly my config for SuperDev mode is the following:
<add-linker name="xsiframe"/>
<set-configuration-property name="devModeRedirectEnabled" value="true"/>
<set-property name="compiler.useSourceMaps" value="true" />
<set-property name="user.agent" value="safari"/>
<collapse-all-properties />
As result GWT compiles only one permutation:
binding: user.agent=safari
binding: compiler.useSourceMaps=true
binding: locale=en
Compiling module com.mycompany.Main
...
Compiling 1 permutation
Compiling permutation 0...
Source Maps Enabled
Compile of permutations succeeded

Answer 2

This can happen if you add locales but do not add the en locale explicitly and/or don't "remove" the default locale and you didn't Dev Mode Off before loading the page in your browser.
For instance, in my module, I had:
<extend-property name="locale" values="fr" />
<set-property-fallback name="locale" value="fr"/>
With this setting, there are 2 locales: fr and default (but the default locale is no longer used, as I override the fallback to fr).
When launching SuperDevMode, it compiles 2 permutations (probably because it forces the locale to en but doesn't actually checks whether such a locale exists in the module).
I had previously launched the app and turned Dev Mode On, but then stopped and restarted the SuperDevMode. When I refresh the page in Chrome, because it's still in dev mode (the state is stored in localStorage), it loads the script from SuperDevMode and tries to load the source maps right away, and this fails as the SuperDevMode compiled 2 permutations and not just one.
Clicking Dev Mode On and Compile forces the SuperDevMode to recompile using the properties from the browser environment (locale=fr here, as it's the fallback). It thus compiles a single permutation and source maps work again.
In my specific case, I needed a single permutation; all I had to do was to add <set-property name="locale" value="fr"/>.
You must be in a similar situation.
I'm sorry that's all the information I can share. Nothing authoritative.