histedit: move all arguments checks to the beginning of the command

This changeset move all checks and raises related to arguments
validation to the top of the file. This gathers all the logic in one
place and clarifies the code doing actual work. This paves the way for
splitting this gigantic function in separated functions.

A `goal` variable is introduced in the process. It holds the action to
be done by this invocation (new, continue or abort).

An invalid invocation is found in the process (the new code is a bit stricter).

hgext/histedit.py

@@ -428,7 +428,7 b" actiontable = {'p': pick,"
       _('force outgoing even for unrelated repositories')),
      ('r', 'rev', [], _('first revision to be edited'))],
      _("[PARENT]"))
-def histedit(ui, repo, *parent, **opts):
+def histedit(ui, repo, *freeargs, **opts):
     """interactively edit changeset history
     """
     # TODO only abort if we try and histedit mq patches, not just
@@ -437,13 +437,43 b' def histedit(ui, repo, *parent, **opts):'
     if mq and mq.applied:
         raise util.Abort(_('source has mq patches applied'))
 
-    parent = list(parent) + opts.get('rev', [])
+    # basic argument incompatibility processing
+    outg = opts.get('outgoing')
+    cont = opts.get('continue')
+    abort = opts.get('abort')
+    force = opts.get('force')
+    rules = opts.get('commands', '')
+    revs = opts.get('rev', [])
+    goal = 'new' # This invocation goal, in new, continue, abort
+    if force and not outg:
+        raise util.Abort(_('--force only allowed with --outgoing'))
+    if cont:
+        if util.any((outg, abort, revs, freeargs, rules)):
+            raise util.Abort(_('no arguments allowed with --continue'))
+        goal = 'continue'
+    elif abort:
+        if util.any((outg, revs, freeargs, rules)):
+            raise util.Abort(_('no arguments allowed with --abort'))
+        goal = 'abort'
+    else:
+        if os.path.exists(os.path.join(repo.path, 'histedit-state')):
+            raise util.Abort(_('history edit already in progress, try '
+                               '--continue or --abort'))
+        if outg:
+            if revs:
+                raise util.Abort(_('no revisions allowed with --outgoing'))
+            if len(freeargs) > 1:
+                raise util.Abort(
+                    _('only one repo argument allowed with --outgoing'))
+        else:
+            parent = list(freeargs) + opts.get('rev', [])
+            if len(parent) != 1:
+                raise util.Abort(
+                    _('histedit requires exactly one parent revision'))
+
     if opts.get('outgoing'):
-        if len(parent) > 1:
-            raise util.Abort(
-                _('only one repo argument allowed with --outgoing'))
-        elif parent:
-            parent = parent[0]
+        if freeargs:
+            parent = freeargs[0]
 
         dest = ui.expandpath(parent or 'default-push', parent or 'default')
         dest, revs = hg.parseurl(dest, None)[:2]
@@ -460,22 +490,17 b' def histedit(ui, repo, *parent, **opts):'
         # contains special revset characters like ":" the revset
         # parser can choke.
         parent = [node.hex(n) for n in discovery.findcommonoutgoing(
-            repo, other, revs, force=opts.get('force')).missing[0:1]]
-    else:
-        if opts.get('force'):
-            raise util.Abort(_('--force only allowed with --outgoing'))
+            repo, other, revs, force=force).missing[0:1]]
+        if not parent:
+            raise util.Abort(_('no outgoing ancestors'))
 
-    if opts.get('continue', False):
-        if len(parent) != 0:
-            raise util.Abort(_('no arguments allowed with --continue'))
+    if goal == 'continue':
         (parentctxnode, rules, keep, topmost, replacements) = readstate(repo)
         currentparent, wantnull = repo.dirstate.parents()
         parentctx = repo[parentctxnode]
         parentctx, repl = bootstrapcontinue(ui, repo, parentctx, rules, opts)
         replacements.extend(repl)
-    elif opts.get('abort', False):
-        if len(parent) != 0:
-            raise util.Abort(_('no arguments allowed with --abort'))
+    elif goal == 'abort':
         (parentctxnode, rules, keep, topmost, replacements) = readstate(repo)
         mapping, tmpnodes, leafs, _ntm = processreplacement(repo, replacements)
         ui.debug('restore wc to old parent %s\n' % node.short(topmost))
@@ -486,14 +511,9 b' def histedit(ui, repo, *parent, **opts):'
         return
     else:
         cmdutil.bailifchanged(repo)
-        if os.path.exists(os.path.join(repo.path, 'histedit-state')):
-            raise util.Abort(_('history edit already in progress, try '
-                               '--continue or --abort'))
 
         topmost, empty = repo.dirstate.parents()
 
-        if len(parent) != 1:
-            raise util.Abort(_('histedit requires exactly one parent revision'))
         parent = scmutil.revsingle(repo, parent[0]).node()
 
         keep = opts.get('keep', False)
@@ -503,7 +523,6 b' def histedit(ui, repo, *parent, **opts):'
                              node.short(parent))
 
         ctxs = [repo[r] for r in revs]
-        rules = opts.get('commands', '')
         if not rules:
             rules = '\n'.join([makedesc(c) for c in ctxs])
             rules += '\n\n'

tests/test-histedit-non-commute.t

@@ -240,7 +240,7 b' edit the history, this time with a fold '
 
   $ echo 'I can haz no commute' > e
   $ hg resolve --mark e
-  $ hg histedit --commands $EDITED --continue 2>&1 | fixbundle
+  $ hg histedit --continue 2>&1 | fixbundle
   0 files updated, 0 files merged, 0 files removed, 0 files unresolved
   merging e
   warning: conflicts during merge.