--- a/mercurial/commands.py	Sat Nov 07 00:13:05 2009 +0100
+++ b/mercurial/commands.py	Sat Nov 07 01:46:27 2009 +0100
@@ -1029,15 +1029,12 @@
 
     # check username
     ui.status(_("Checking username...\n"))
-    user = os.environ.get("HGUSER")
-    if user is None:
-        user = ui.config("ui", "username")
-    if user is None:
-        user = os.environ.get("EMAIL")
-    if not user:
-        ui.warn(" ")
-        ui.username()
+    try:
+        user = ui.username()
+    except util.Abort, e:
+        ui.write(" %s\n" % e)
         ui.write(_(" (specify a username in your .hgrc file)\n"))
+        problems += 1
 
     if not problems:
         ui.status(_("No problems detected\n"))

--- a/tests/test-install	Sat Nov 07 00:13:05 2009 +0100
+++ b/tests/test-install	Sat Nov 07 01:46:27 2009 +0100
@@ -1,3 +1,10 @@
 #!/bin/sh
 
+echo '% hg debuginstall'
 hg debuginstall
+
+echo '% hg debuginstall with no username'
+HGUSER= hg debuginstall
+
+# Happy End
+true

--- a/tests/test-install.out	Sat Nov 07 00:13:05 2009 +0100
+++ b/tests/test-install.out	Sat Nov 07 01:46:27 2009 +0100
@@ -1,3 +1,4 @@
+% hg debuginstall
 Checking encoding (ascii)...
 Checking extensions...
 Checking templates...
@@ -5,3 +6,13 @@
 Checking commit editor...
 Checking username...
 No problems detected
+% hg debuginstall with no username
+Checking encoding (ascii)...
+Checking extensions...
+Checking templates...
+Checking patch...
+Checking commit editor...
+Checking username...
+ Please specify a username.
+ (specify a username in your .hgrc file)
+1 problems detected, please check your install!