import: move tryone closure in cmdutil

We extract the `tryone` function into the `cmdutil` module. A lot of the command
context have to be passed to the utility function, but having and explicit
declaration will allow extension to wrap it. This will allows use to make
changeset evolution related experiment in dedicated extension.

Improving the API of this function is noble goal but outside of the scope of
this patches.

mercurial/cmdutil.py

@@ -542,6 +542,131 b' def service(opts, parentfn=None, initfn='
     if runfn:
         return runfn()
 
+def tryimportone(ui, repo, hunk, parents, opts, msgs, updatefunc):
+    """Utility function used by commands.import to import a single patch
+
+    This function is explicitly defined here to help the evolve extension to
+    wrap this part of the import logic.
+
+    The API is currently a bit ugly because it a simple code translation from
+    the import command. Feel free to make it better.
+
+    :hunk: a patch (as a binary string)
+    :parents: nodes that will be parent of the created commit
+    :opts: the full dict of option passed to the import command
+    :msgs: list to save commit message to.
+           (used in case we need to save it when failing)
+    :updatefunc: a function that update a repo to a given node
+                 updatefunc(<repo>, <node>)
+    """
+    tmpname, message, user, date, branch, nodeid, p1, p2 = \
+        patch.extract(ui, hunk)
+
+    editor = commiteditor
+    if opts.get('edit'):
+        editor = commitforceeditor
+    update = not opts.get('bypass')
+    strip = opts["strip"]
+    sim = float(opts.get('similarity') or 0)
+    if not tmpname:
+        return (None, None)
+    msg = _('applied to working directory')
+
+    try:
+        cmdline_message = logmessage(ui, opts)
+        if cmdline_message:
+            # pickup the cmdline msg
+            message = cmdline_message
+        elif message:
+            # pickup the patch msg
+            message = message.strip()
+        else:
+            # launch the editor
+            message = None
+        ui.debug('message:\n%s\n' % message)
+
+        if len(parents) == 1:
+            parents.append(repo[nullid])
+        if opts.get('exact'):
+            if not nodeid or not p1:
+                raise util.Abort(_('not a Mercurial patch'))
+            p1 = repo[p1]
+            p2 = repo[p2 or nullid]
+        elif p2:
+            try:
+                p1 = repo[p1]
+                p2 = repo[p2]
+                # Without any options, consider p2 only if the
+                # patch is being applied on top of the recorded
+                # first parent.
+                if p1 != parents[0]:
+                    p1 = parents[0]
+                    p2 = repo[nullid]
+            except error.RepoError:
+                p1, p2 = parents
+        else:
+            p1, p2 = parents
+
+        n = None
+        if update:
+            if p1 != parents[0]:
+                updatefunc(repo, p1.node())
+            if p2 != parents[1]:
+                repo.setparents(p1.node(), p2.node())
+
+            if opts.get('exact') or opts.get('import_branch'):
+                repo.dirstate.setbranch(branch or 'default')
+
+            files = set()
+            patch.patch(ui, repo, tmpname, strip=strip, files=files,
+                        eolmode=None, similarity=sim / 100.0)
+            files = list(files)
+            if opts.get('no_commit'):
+                if message:
+                    msgs.append(message)
+            else:
+                if opts.get('exact') or p2:
+                    # If you got here, you either use --force and know what
+                    # you are doing or used --exact or a merge patch while
+                    # being updated to its first parent.
+                    m = None
+                else:
+                    m = scmutil.matchfiles(repo, files or [])
+                n = repo.commit(message, opts.get('user') or user,
+                                opts.get('date') or date, match=m,
+                                editor=editor)
+        else:
+            if opts.get('exact') or opts.get('import_branch'):
+                branch = branch or 'default'
+            else:
+                branch = p1.branch()
+            store = patch.filestore()
+            try:
+                files = set()
+                try:
+                    patch.patchrepo(ui, repo, p1, store, tmpname, strip,
+                                    files, eolmode=None)
+                except patch.PatchError, e:
+                    raise util.Abort(str(e))
+                memctx = context.makememctx(repo, (p1.node(), p2.node()),
+                                            message,
+                                            opts.get('user') or user,
+                                            opts.get('date') or date,
+                                            branch, files, store,
+                                            editor=commiteditor)
+                repo.savecommitmessage(memctx.description())
+                n = memctx.commit()
+            finally:
+                store.close()
+        if opts.get('exact') and hex(n) != nodeid:
+            raise util.Abort(_('patch is damaged or loses information'))
+        if n:
+            # i18n: refers to a short changeset id
+            msg = _('created %s') % short(n)
+        return (msg, n)
+    finally:
+        os.unlink(tmpname)
+
 def export(repo, revs, template='hg-%h.patch', fp=None, switch_parent=False,
            opts=None):
     '''export changesets as hg patches.'''

mercurial/commands.py

@@ -3678,10 +3678,6 b' def import_(ui, repo, patch1=None, *patc'
     if date:
         opts['date'] = util.parsedate(date)
 
-    editor = cmdutil.commiteditor
-    if opts.get('edit'):
-        editor = cmdutil.commitforceeditor
-
     update = not opts.get('bypass')
     if not update and opts.get('no_commit'):
         raise util.Abort(_('cannot use --no-commit with --bypass'))
@@ -3700,112 +3696,9 b' def import_(ui, repo, patch1=None, *patc'
         cmdutil.bailifchanged(repo)
 
     base = opts["base"]
-    strip = opts["strip"]
     wlock = lock = tr = None
     msgs = []
 
-    def tryone(ui, hunk, parents):
-        tmpname, message, user, date, branch, nodeid, p1, p2 = \
-            patch.extract(ui, hunk)
-
-        if not tmpname:
-            return (None, None)
-        msg = _('applied to working directory')
-
-        try:
-            cmdline_message = cmdutil.logmessage(ui, opts)
-            if cmdline_message:
-                # pickup the cmdline msg
-                message = cmdline_message
-            elif message:
-                # pickup the patch msg
-                message = message.strip()
-            else:
-                # launch the editor
-                message = None
-            ui.debug('message:\n%s\n' % message)
-
-            if len(parents) == 1:
-                parents.append(repo[nullid])
-            if opts.get('exact'):
-                if not nodeid or not p1:
-                    raise util.Abort(_('not a Mercurial patch'))
-                p1 = repo[p1]
-                p2 = repo[p2 or nullid]
-            elif p2:
-                try:
-                    p1 = repo[p1]
-                    p2 = repo[p2]
-                    # Without any options, consider p2 only if the
-                    # patch is being applied on top of the recorded
-                    # first parent.
-                    if p1 != parents[0]:
-                        p1 = parents[0]
-                        p2 = repo[nullid]
-                except error.RepoError:
-                    p1, p2 = parents
-            else:
-                p1, p2 = parents
-
-            n = None
-            if update:
-                if p1 != parents[0]:
-                    hg.clean(repo, p1.node())
-                if p2 != parents[1]:
-                    repo.setparents(p1.node(), p2.node())
-
-                if opts.get('exact') or opts.get('import_branch'):
-                    repo.dirstate.setbranch(branch or 'default')
-
-                files = set()
-                patch.patch(ui, repo, tmpname, strip=strip, files=files,
-                            eolmode=None, similarity=sim / 100.0)
-                files = list(files)
-                if opts.get('no_commit'):
-                    if message:
-                        msgs.append(message)
-                else:
-                    if opts.get('exact') or p2:
-                        # If you got here, you either use --force and know what
-                        # you are doing or used --exact or a merge patch while
-                        # being updated to its first parent.
-                        m = None
-                    else:
-                        m = scmutil.matchfiles(repo, files or [])
-                    n = repo.commit(message, opts.get('user') or user,
-                                    opts.get('date') or date, match=m,
-                                    editor=editor)
-            else:
-                if opts.get('exact') or opts.get('import_branch'):
-                    branch = branch or 'default'
-                else:
-                    branch = p1.branch()
-                store = patch.filestore()
-                try:
-                    files = set()
-                    try:
-                        patch.patchrepo(ui, repo, p1, store, tmpname, strip,
-                                        files, eolmode=None)
-                    except patch.PatchError, e:
-                        raise util.Abort(str(e))
-                    memctx = context.makememctx(repo, (p1.node(), p2.node()),
-                                                message,
-                                                opts.get('user') or user,
-                                                opts.get('date') or date,
-                                                branch, files, store,
-                                                editor=cmdutil.commiteditor)
-                    repo.savecommitmessage(memctx.description())
-                    n = memctx.commit()
-                finally:
-                    store.close()
-            if opts.get('exact') and hex(n) != nodeid:
-                raise util.Abort(_('patch is damaged or loses information'))
-            if n:
-                # i18n: refers to a short changeset id
-                msg = _('created %s') % short(n)
-            return (msg, n)
-        finally:
-            os.unlink(tmpname)
 
     try:
         try:
@@ -3826,7 +3719,8 b' def import_(ui, repo, patch1=None, *patc'
 
                 haspatch = False
                 for hunk in patch.split(patchfile):
-                    (msg, node) = tryone(ui, hunk, parents)
+                    (msg, node) = cmdutil.tryimportone(ui, repo, hunk, parents,
+                                                       opts, msgs, hg.clean)
                     if msg:
                         haspatch = True
                         ui.note(msg + '\n')