mq: Parse commit message after we find start of changeset patch

patch.extract extracts just the message below HG changeset patch. So to not
parse comments above the patch, we reset the message if we find a changeset
patch as we know the commit message comes after the changeset patch data.
This is similar to the behavior of patch.extract.

The drawback of this approach, after a qref -e the comment above HG changeset
patch is gone. Without this patch the message would become part of the commit
message in the HG changset patch part.

hgext/mq.py

@@ -105,6 +105,7 b' class patchheader(object):'
                     message.append(line)
                     format = None
             elif line == '# HG changeset patch':
+                message = []
                 format = "hgpatch"
             elif (format != "tagdone" and (line.startswith("Subject: ") or
                                            line.startswith("subject: "))):

tests/test-mq-qimport

@@ -27,6 +27,38 b' cd repo'
 echo % qimport non-existing-file
 hg qimport non-existing-file
 
+echo % import email
+hg qimport --push -n email - <<EOF
+From: Username in email <[e-mail]>
+Subject: [PATCH] Message in email
+Date: Fri, 02 Jan 1970 00:00:00 +0000
+
+Text before patch.
+
+# HG changeset patch
+# User Username in patch <[e-mail]>
+# Date 0 0
+# Node ID 1a706973a7d84cb549823634a821d9bdf21c6220
+# Parent  0000000000000000000000000000000000000000
+First line of commit message.
+
+More text in commit message.
+
+diff --git a/x b/x
+new file mode 100644
+--- /dev/null
++++ b/x
+@@ -0,0 +1,1 @@
++new file
+Text after patch.
+
+EOF
+
+echo % hg tip -v
+hg tip -v
+hg qpop
+hg qdelete email
+
 echo % import URL
 echo foo >> foo
 hg add foo

tests/test-mq-qimport.out

@@ -1,5 +1,25 b''
 % qimport non-existing-file
 abort: unable to read non-existing-file
+% import email
+adding email to series file
+applying email
+now at: email
+% hg tip -v
+changeset:   0:1a706973a7d8
+tag:         qtip
+tag:         tip
+tag:         email
+tag:         qbase
+user:        Username in patch <[e-mail]>
+date:        Thu Jan 01 00:00:00 1970 +0000
+files:       x
+description:
+First line of commit message.
+
+More text in commit message.
+
+
+patch queue now empty
 % import URL
 adding url.diff to series file
 url.diff