merge(3p/git): Merge git subtree at v2.29.2

This also bumps the stable nixpkgs to 20.09 as of 2020-11-21, because
there is some breakage in the git build related to the netrc
credentials helper which someone has taken care of in nixpkgs.

The stable channel is not used for anything other than git, so this
should be fine.

Change-Id: I3575a19dab09e1e9556cf8231d717de9890484fb

third_party/git/contrib/hg-to-git/hg-to-git.py

@@ -42,7 +42,7 @@ hgnewcsets = 0
 
 def usage():
 
-        print """\
+        print("""\
 %s: [OPTIONS] <hgprj>
 
 options:
@@ -54,7 +54,7 @@ options:
 
 required:
     hgprj:  name of the HG project to import (directory)
-""" % sys.argv[0]
+""" % sys.argv[0])
 
 #------------------------------------------------------------------------------
 
@@ -104,22 +104,22 @@ os.chdir(hgprj)
 if state:
     if os.path.exists(state):
         if verbose:
-            print 'State does exist, reading'
+            print('State does exist, reading')
         f = open(state, 'r')
         hgvers = pickle.load(f)
     else:
-        print 'State does not exist, first run'
+        print('State does not exist, first run')
 
 sock = os.popen('hg tip --template "{rev}"')
 tip = sock.read()
 if sock.close():
     sys.exit(1)
 if verbose:
-    print 'tip is', tip
+    print('tip is', tip)
 
 # Calculate the branches
 if verbose:
-    print 'analysing the branches...'
+    print('analysing the branches...')
 hgchildren["0"] = ()
 hgparents["0"] = (None, None)
 hgbranch["0"] = "master"
@@ -154,15 +154,15 @@ for cset in range(1, int(tip) + 1):
         else:
             hgbranch[str(cset)] = "branch-" + str(cset)
 
-if not hgvers.has_key("0"):
-    print 'creating repository'
+if "0" not in hgvers:
+    print('creating repository')
     os.system('git init')
 
 # loop through every hg changeset
 for cset in range(int(tip) + 1):
 
     # incremental, already seen
-    if hgvers.has_key(str(cset)):
+    if str(cset) in hgvers:
         continue
     hgnewcsets += 1
 
@@ -180,27 +180,27 @@ for cset in range(int(tip) + 1):
     os.write(fdcomment, csetcomment)
     os.close(fdcomment)
 
-    print '-----------------------------------------'
-    print 'cset:', cset
-    print 'branch:', hgbranch[str(cset)]
-    print 'user:', user
-    print 'date:', date
-    print 'comment:', csetcomment
+    print('-----------------------------------------')
+    print('cset:', cset)
+    print('branch:', hgbranch[str(cset)])
+    print('user:', user)
+    print('date:', date)
+    print('comment:', csetcomment)
     if parent:
-	print 'parent:', parent
+        print('parent:', parent)
     if mparent:
-        print 'mparent:', mparent
+        print('mparent:', mparent)
     if tag:
-        print 'tag:', tag
-    print '-----------------------------------------'
+        print('tag:', tag)
+    print('-----------------------------------------')
 
     # checkout the parent if necessary
     if cset != 0:
         if hgbranch[str(cset)] == "branch-" + str(cset):
-            print 'creating new branch', hgbranch[str(cset)]
+            print('creating new branch', hgbranch[str(cset)])
             os.system('git checkout -b %s %s' % (hgbranch[str(cset)], hgvers[parent]))
         else:
-            print 'checking out branch', hgbranch[str(cset)]
+            print('checking out branch', hgbranch[str(cset)])
             os.system('git checkout %s' % hgbranch[str(cset)])
 
     # merge
@@ -209,7 +209,7 @@ for cset in range(int(tip) + 1):
             otherbranch = hgbranch[mparent]
         else:
             otherbranch = hgbranch[parent]
-        print 'merging', otherbranch, 'into', hgbranch[str(cset)]
+        print('merging', otherbranch, 'into', hgbranch[str(cset)])
         os.system(getgitenv(user, date) + 'git merge --no-commit -s ours "" %s %s' % (hgbranch[str(cset)], otherbranch))
 
     # remove everything except .git and .hg directories
@@ -233,12 +233,12 @@ for cset in range(int(tip) + 1):
 
     # delete branch if not used anymore...
     if mparent and len(hgchildren[str(cset)]):
-        print "Deleting unused branch:", otherbranch
+        print("Deleting unused branch:", otherbranch)
         os.system('git branch -d %s' % otherbranch)
 
     # retrieve and record the version
     vvv = os.popen('git show --quiet --pretty=format:%H').read()
-    print 'record', cset, '->', vvv
+    print('record', cset, '->', vvv)
     hgvers[str(cset)] = vvv
 
 if hgnewcsets >= opt_nrepack and opt_nrepack != -1:
@@ -247,7 +247,7 @@ if hgnewcsets >= opt_nrepack and opt_nrepack != -1:
 # write the state for incrementals
 if state:
     if verbose:
-        print 'Writing state'
+        print('Writing state')
     f = open(state, 'w')
     pickle.dump(hgvers, f)