[PATCH 1 of 3] extdiff: prepare sections of dodiff() for conditionalizing

[Matt Harbison]

# HG changeset patch
# User Matt Harbison <matt_harbison at yahoo.com>
# Date 1441846089 14400
#      Wed Sep 09 20:48:09 2015 -0400
# Node ID 1ddeec36d049de2232b7a609d6433b2942ff9172
# Parent  ea489d94e1dc1fc3dc1dcbef1c86c18c49605ed1
extdiff: prepare sections of dodiff() for conditionalizing

This is purely indenting under an unconditional branch, so that the actual
changes in the next patch are clear.  Feel free to fold them if desired.

diff --git a/hgext/extdiff.py b/hgext/extdiff.py
--- a/hgext/extdiff.py
+++ b/hgext/extdiff.py
@@ -146,72 +146,77 @@
     subrepos=opts.get('subrepos')
 
     matcher = scmutil.match(repo[node2], pats, opts)
-    mod_a, add_a, rem_a = map(set, repo.status(node1a, node2, matcher,
-                                               listsubrepos=subrepos)[:3])
-    if do3way:
-        mod_b, add_b, rem_b = map(set, repo.status(node1b, node2, matcher,
+
+    if True:
+        mod_a, add_a, rem_a = map(set, repo.status(node1a, node2, matcher,
                                                    listsubrepos=subrepos)[:3])
-    else:
-        mod_b, add_b, rem_b = set(), set(), set()
-    modadd = mod_a | add_a | mod_b | add_b
-    common = modadd | rem_a | rem_b
-    if not common:
-        return 0
+        if do3way:
+            mod_b, add_b, rem_b = map(set,
+                                      repo.status(node1b, node2, matcher,
+                                                  listsubrepos=subrepos)[:3])
+        else:
+            mod_b, add_b, rem_b = set(), set(), set()
+        modadd = mod_a | add_a | mod_b | add_b
+        common = modadd | rem_a | rem_b
+        if not common:
+            return 0
 
     tmproot = tempfile.mkdtemp(prefix='extdiff.')
     try:
-        # Always make a copy of node1a (and node1b, if applicable)
-        dir1a_files = mod_a | rem_a | ((mod_b | add_b) - add_a)
-        dir1a = snapshot(ui, repo, dir1a_files, node1a, tmproot, subrepos)[0]
-        rev1a = '@%d' % repo[node1a].rev()
-        if do3way:
-            dir1b_files = mod_b | rem_b | ((mod_a | add_a) - add_b)
-            dir1b = snapshot(ui, repo, dir1b_files, node1b, tmproot,
+        if True:
+            # Always make a copy of node1a (and node1b, if applicable)
+            dir1a_files = mod_a | rem_a | ((mod_b | add_b) - add_a)
+            dir1a = snapshot(ui, repo, dir1a_files, node1a, tmproot,
                              subrepos)[0]
-            rev1b = '@%d' % repo[node1b].rev()
-        else:
-            dir1b = None
-            rev1b = ''
+            rev1a = '@%d' % repo[node1a].rev()
+            if do3way:
+                dir1b_files = mod_b | rem_b | ((mod_a | add_a) - add_b)
+                dir1b = snapshot(ui, repo, dir1b_files, node1b, tmproot,
+                                 subrepos)[0]
+                rev1b = '@%d' % repo[node1b].rev()
+            else:
+                dir1b = None
+                rev1b = ''
 
-        fns_and_mtime = []
+            fns_and_mtime = []
 
-        # If node2 in not the wc or there is >1 change, copy it
-        dir2root = ''
-        rev2 = ''
-        if node2:
-            dir2 = snapshot(ui, repo, modadd, node2, tmproot, subrepos)[0]
-            rev2 = '@%d' % repo[node2].rev()
-        elif len(common) > 1:
-            #we only actually need to get the files to copy back to
-            #the working dir in this case (because the other cases
-            #are: diffing 2 revisions or single file -- in which case
-            #the file is already directly passed to the diff tool).
-            dir2, fns_and_mtime = snapshot(ui, repo, modadd, None, tmproot,
-                                           subrepos)
-        else:
-            # This lets the diff tool open the changed file directly
-            dir2 = ''
-            dir2root = repo.root
+            # If node2 in not the wc or there is >1 change, copy it
+            dir2root = ''
+            rev2 = ''
+            if node2:
+                dir2 = snapshot(ui, repo, modadd, node2, tmproot, subrepos)[0]
+                rev2 = '@%d' % repo[node2].rev()
+            elif len(common) > 1:
+                #we only actually need to get the files to copy back to
+                #the working dir in this case (because the other cases
+                #are: diffing 2 revisions or single file -- in which case
+                #the file is already directly passed to the diff tool).
+                dir2, fns_and_mtime = snapshot(ui, repo, modadd, None, tmproot,
+                                               subrepos)
+            else:
+                # This lets the diff tool open the changed file directly
+                dir2 = ''
+                dir2root = repo.root
 
-        label1a = rev1a
-        label1b = rev1b
-        label2 = rev2
+            label1a = rev1a
+            label1b = rev1b
+            label2 = rev2
 
-        # If only one change, diff the files instead of the directories
-        # Handle bogus modifies correctly by checking if the files exist
-        if len(common) == 1:
-            common_file = util.localpath(common.pop())
-            dir1a = os.path.join(tmproot, dir1a, common_file)
-            label1a = common_file + rev1a
-            if not os.path.isfile(dir1a):
-                dir1a = os.devnull
-            if do3way:
-                dir1b = os.path.join(tmproot, dir1b, common_file)
-                label1b = common_file + rev1b
-                if not os.path.isfile(dir1b):
-                    dir1b = os.devnull
-            dir2 = os.path.join(dir2root, dir2, common_file)
-            label2 = common_file + rev2
+            # If only one change, diff the files instead of the directories
+            # Handle bogus modifies correctly by checking if the files exist
+            if len(common) == 1:
+                common_file = util.localpath(common.pop())
+                dir1a = os.path.join(tmproot, dir1a, common_file)
+                label1a = common_file + rev1a
+                if not os.path.isfile(dir1a):
+                    dir1a = os.devnull
+                if do3way:
+                    dir1b = os.path.join(tmproot, dir1b, common_file)
+                    label1b = common_file + rev1b
+                    if not os.path.isfile(dir1b):
+                        dir1b = os.devnull
+                dir2 = os.path.join(dir2root, dir2, common_file)
+                label2 = common_file + rev2
 
         # Function to quote file/dir names in the argument string.
         # When not operating in 3-way mode, an empty string is