diff --git a/mercurial/dispatch.py b/mercurial/dispatch.py
--- a/mercurial/dispatch.py
+++ b/mercurial/dispatch.py
@@ -283,12 +283,19 @@ def _runcatch(req):
                 # We found an untested extension. It's likely the culprit.
                 worst = name, 'unknown', report
                 break
-            if compare not in testedwith.split() and testedwith != 'internal':
-                tested = [tuplever(v) for v in testedwith.split()]
-                lower = [t for t in tested if t < ct]
-                nearest = max(lower or tested)
-                if worst[0] is None or nearest < worst[1]:
-                    worst = name, nearest, report
+
+            # Never blame on extensions bundled with Mercurial.
+            if testedwith == 'internal':
+                continue
+
+            tested = [tuplever(t) for t in testedwith.split()]
+            if ct in tested:
+                continue
+
+            lower = [t for t in tested if t < ct]
+            nearest = max(lower or tested)
+            if worst[0] is None or nearest < worst[1]:
+                worst = name, nearest, report
         if worst[0] is not None:
             name, testedwith, report = worst
             if not isinstance(testedwith, str):
@@ -315,7 +322,10 @@ def _runcatch(req):
 
 def tuplever(v):
     try:
-        return tuple([int(i) for i in v.split('.')])
+        # Assertion: tuplever is only used for extension compatibility
+        # checking. Otherwise, the discarding of extra version fields is
+        # incorrect.
+        return tuple([int(i) for i in v.split('.')[0:2]])
     except ValueError:
         return tuple()
 
diff --git a/tests/test-extension.t b/tests/test-extension.t
--- a/tests/test-extension.t
+++ b/tests/test-extension.t
@@ -858,7 +858,7 @@ Broken disabled extension and command:
   [255]
 
   $ cat > throw.py <<EOF
-  > from mercurial import cmdutil, commands
+  > from mercurial import cmdutil, commands, util
   > cmdtable = {}
   > command = cmdutil.command(cmdtable)
   > class Bogon(Exception): pass
@@ -910,7 +910,7 @@ If the extensions declare outdated versi
   $ hg --config extensions.throw=throw.py --config extensions.older=older.py \
   >   throw 2>&1 | egrep '^\*\*'
   ** Unknown exception encountered with possibly-broken third-party extension older
-  ** which supports versions 1.9.3 of Mercurial.
+  ** which supports versions 1.9 of Mercurial.
   ** Please disable older and try your action again.
   ** If that fixes the bug please report it to the extension author.
   ** Python * (glob)
@@ -923,7 +923,7 @@ One extension only tested with older, on
   $ hg --config extensions.throw=throw.py --config extensions.older=older.py \
   >   throw 2>&1 | egrep '^\*\*'
   ** Unknown exception encountered with possibly-broken third-party extension older
-  ** which supports versions 1.9.3 of Mercurial.
+  ** which supports versions 1.9 of Mercurial.
   ** Please disable older and try your action again.
   ** If that fixes the bug please report it to the extension author.
   ** Python * (glob)
@@ -936,7 +936,7 @@ Older extension is tested with current v
   $ hg --config extensions.throw=throw.py --config extensions.older=older.py \
   >   throw 2>&1 | egrep '^\*\*'
   ** Unknown exception encountered with possibly-broken third-party extension throw
-  ** which supports versions 2.1.1 of Mercurial.
+  ** which supports versions 2.1 of Mercurial.
   ** Please disable throw and try your action again.
   ** If that fixes the bug please report it to http://example.com/bts
   ** Python * (glob)
@@ -954,6 +954,17 @@ Declare the version as supporting this h
   ** Mercurial Distributed SCM (*) (glob)
   ** Extensions loaded: throw
 
+Patch version is ignored during compatibility check
+  $ echo "testedwith = '3.2'" >> throw.py
+  $ echo "util.version = lambda:'3.2.2'" >> throw.py
+  $ rm -f throw.pyc throw.pyo
+  $ hg --config extensions.throw=throw.py throw 2>&1 | egrep '^\*\*'
+  ** unknown exception encountered, please report by visiting
+  ** http://mercurial.selenic.com/wiki/BugTracker
+  ** Python * (glob)
+  ** Mercurial Distributed SCM (*) (glob)
+  ** Extensions loaded: throw
+
 Test version number support in 'hg version':
   $ echo '__version__ = (1, 2, 3)' >> throw.py
   $ rm -f throw.pyc throw.pyo