build: port all python from python2 to python3

ONIE still shipped python2-only code throughout the tree.  Port every
python asset to python3 so the build no longer needs a python2
interpreter (a prerequisite for moving to a modern Debian build host)
and so nothing in contrib/ or the machine tests is left on a dead
runtime.  This change deliberately does NOT touch the CI Dockerfile, so
the cross-toolchain cache key is preserved (the Debian-13 build-host
bump is deferred to the toolchain-upgrade step, where it must land
alongside crosstool-NG/GCC -- the current GCC 8.3.0 toolchain cannot be
built on a GCC 14 host).

Build path:
  - build-config/scripts/mk-part-table.py (the only python invoked by
    the image build -- it writes the recovery ISO MBR partition table):
    env python3 shebang, integer division (/ -> //) so CHS values stay
    ints, and the ISO opened in binary mode ('r+b') so struct.pack()
    bytes are written correctly.  A shebang-only change is insufficient;
    without the // and binary fixes the script silently writes a wrong
    partition table under python3.  Verified to emit a correct MBR
    (0xaa55 signature, 0x80 boot flag, 0xEF EFI type) on a test image.
  - build-config/Makefile: retarget $(PYTHON) from python2 to python3.
    grub's autogen.sh invokes "${PYTHON:-python}", and a bare "python"
    no longer exists once python2 is gone, so the build must export
    PYTHON=python3 (grub's gentpl.py/import_gcry.py are python3-safe).
    The old block only set PYTHON=python2 when "python" was absent;
    replace it with an exported `PYTHON ?= python3`.  Also switch
    DEBIAN_BUILD_HOST_PACKAGES from python-all-dev/python-sphinx to
    python3-all-dev/python3-sphinx.

Tooling and tests (mechanical 2to3, behaviour preserved):
  - contrib/oce, contrib/onie-server, contrib/git-stats/gitdm (vendored),
    and the machine/*/test DUT scripts: python3 shebangs; print()
    functions; `except E, e` -> `except E as e`; iteritems/iterkeys/
    itervalues -> items/keys/values; has_key -> `in`; raw_input -> input;
    cStringIO/StringIO -> io; py2 stdlib renames (Queue->queue,
    SimpleHTTPServer/SocketServer->http.server/socketserver, thread->
    _thread); sort(cmp=...) -> key=cmp_to_key(...); list() wrapping of
    views/maps that are indexed or sorted; onie-server.py spawns its
    helpers with "python3" instead of "python".
  - contrib/onie-server/proxy-server.py was cp1252-encoded; re-encode it
    as UTF-8 and update the coding declaration so its (Portuguese)
    comments survive the python3 port intact.

Every python file in the tree now passes `python3 -m py_compile`, all
shebang scripts use `#!/usr/bin/env python3`, and no python2-only syntax
remains.

Signed-off-by: Brad House <bhouse@nexthop.ai>
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: bhouse-nexthop

build-config/Makefile

@@ -515,13 +515,11 @@ ifeq ($(FIRMWARE_UPDATE_ENABLE),yes)
   include make/firmware-update.make
 endif
 
-# Pre Debian 11 environments just had /usr/bin/python
-# Now the environment distinguishes between python2 and python3
-# If 'python' is not present, default to python2
-ifeq (, $(shell which python ))
-  export PYTHON=python2
-endif
-
+# Some sub-package build scripts (notably grub's autogen.sh) invoke the
+# interpreter as "${PYTHON:-python}".  A bare "python" no longer exists on
+# modern systems now that python2 is gone, so point $(PYTHON) at python3.
+# (grub's build scripts -- gentpl.py, import_gcry.py -- are python3-safe.)
+export PYTHON ?= python3
 
 #-------------------------------------------------------------------------------
 #
@@ -594,11 +592,11 @@ machine-prefix:
 # The onie/build-config/scripts/onie-build-targets.json file lists
 #  platforms and known working build environments.
 DEBIAN_BUILD_HOST_PACKAGES	= build-essential stgit u-boot-tools util-linux \
-				  gperf device-tree-compiler python-all-dev xorriso \
+				  gperf device-tree-compiler python3-all-dev xorriso \
 				  autoconf automake bison flex texinfo libtool libtool-bin \
 				  gawk libncurses5 libncurses5-dev bc \
 				  dosfstools mtools pkg-config git wget help2man libexpat1 \
-				  libexpat1-dev fakeroot python-sphinx rst2pdf \
+				  libexpat1-dev fakeroot python3-sphinx rst2pdf \
 				  libefivar-dev libnss3-tools libnss3-dev libpopt-dev \
 				  libssl-dev sbsigntool uuid-runtime uuid-dev cpio \
 				  bsdmainutils unzip

build-config/scripts/mk-part-table.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python2
+#!/usr/bin/env python3
 
 from struct import pack
 import sys
@@ -23,8 +23,8 @@
 # See MBR partition table entry format here:
 # http://en.wikipedia.org/wiki/Master_boot_record#Partition_table_entries
 def chs(sector_z):
-    C = sector_z / (63 * 255)
-    H = (sector_z % (63 * 255)) / 63
+    C = sector_z // (63 * 255)
+    H = (sector_z % (63 * 255)) // 63
     # convert zero-based sector to CHS format
     S = (sector_z % 63) + 1
     # munge accord to partition table format
@@ -42,7 +42,7 @@ def chs(sector_z):
 #
 # See the partition table format here:
 # http://en.wikipedia.org/wiki/Master_boot_record#Sector_layout
-f = open(iso, 'r+')
+f = open(iso, 'r+b')
 f.seek(0x1BE)
 f.write(pack("<8BLL48xH", 0x80, s_H, s_S, s_C,
              fs_type, e_H, e_S, e_C, start, length, 0xaa55))

contrib/git-stats/gitdm/ConfigFile.py

@@ -147,10 +147,10 @@ def ReadFileType (filename):
         m = regex_file_type.match (line)
         if not m or len (m.groups ()) != 2:
             ConfigFile.croak ('Funky file type line "%s"' % (line))
-        if not patterns.has_key (m.group (1)):
+        if m.group (1) not in patterns:
             patterns[m.group (1)] = []
         if m.group (1) not in order:
-            print '%s not found, appended to the last order' % m.group (1)
+            print('%s not found, appended to the last order' % m.group (1))
             order.append (m.group (1))
 
         patterns[m.group (1)].append (re.compile (m.group (2), re.IGNORECASE))

contrib/git-stats/gitdm/csvdump.py

@@ -50,7 +50,7 @@ def store_patch(patch):
         ChangeSets.append([patch.commit, str(patch.date),
                            patch.email, domain, author, employer,
                            patch.added, patch.removed])
-        for (filetype, (added, removed)) in patch.filetypes.iteritems():
+        for (filetype, (added, removed)) in patch.filetypes.items():
             FileTypes.append([patch.commit, filetype, added, removed])
 
 

contrib/git-stats/gitdm/database.py

@@ -38,7 +38,7 @@ def emailemployer (self, email, date):
                 for edate, empl in self.employer[i]:
                     if edate > date:
                         return empl
-        print 'OOPS.  ', self.name, self.employer, self.email, email, date
+        print('OOPS.  ', self.name, self.employer, self.email, email, date)
         return None # Should not happen
 
     def addpatch (self, patch):
@@ -118,11 +118,11 @@ def LookupStoreHacker(name, email, mapunknown = True):
 
 
 def AllHackers ():
-    return HackersByID.values ()
+    return list(HackersByID.values ())
 
 def DumpDB ():
     out = open ('database.dump', 'w')
-    names = HackersByName.keys ()
+    names = list(HackersByName.keys ())
     names.sort ()
     for name in names:
         h = HackersByName[name]
@@ -179,7 +179,7 @@ def GetEmployer (name):
         return e
 
 def AllEmployers ():
-    return Employers.values ()
+    return list(Employers.values ())
 
 #
 # Certain obnoxious developers, who will remain nameless (because we
@@ -209,8 +209,8 @@ def applysplits (self):
         self.__init__ (name) # Reset counts just in case
 
     def store (self):
-        if Employers.has_key (self.name):
-            print Employers[self.name]
+        if self.name in Employers:
+            print(Employers[self.name])
             sys.stderr.write ('WARNING: Virtual empl %s overwrites another\n'
                               % (self.name))
         if len (self.splits) == 0:
@@ -229,7 +229,7 @@ def guess_file_type (self, filename, patterns=None, order=None):
         order = order or self.order
 
         for file_type in order:
-            if patterns.has_key (file_type):
+            if file_type in patterns:
                 for patt in patterns[file_type]:
                     if patt.search (filename):
                         return file_type
@@ -255,7 +255,7 @@ def MixVirtuals ():
 EmailAliases = { }
 
 def AddEmailAlias (variant, canonical):
-    if EmailAliases.has_key (variant):
+    if variant in EmailAliases:
         sys.stderr.write ('Duplicate email alias for %s\n' % (variant))
     EmailAliases[variant] = canonical
 
@@ -282,7 +282,7 @@ def AddEmailEmployerMapping (email, employer, end = nextyear):
         for i in range (0, len(l)):
             date, xempl = l[i]
             if date == end:  # probably both nextyear
-                print 'WARNING: duplicate email/empl for %s' % (email)
+                print('WARNING: duplicate email/empl for %s' % (email))
             if date > end:
                 l.insert (i, (end, empl))
                 return
@@ -299,7 +299,7 @@ def MapToEmployer (email, unknown = 0):
         pass
     namedom = email.split ('@')
     if len (namedom) < 2:
-        print 'Oops...funky email %s' % email
+        print('Oops...funky email %s' % email)
         return [(nextyear, GetEmployer ('Funky'))]
     s = namedom[1].split ('.')
     for dots in range (len (s) - 2, -1, -1):

contrib/git-stats/gitdm/findoldfiles

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python3
 #
 # Another quick hack of a script to find files unchanged
 # since a given commit.
@@ -19,7 +19,7 @@ def CheckFile(file):
     git = os.popen('git log --pretty=oneline -1 ' + file, 'r')
     line = git.readline()
     if line.startswith(OriginalSin):
-        print file
+        print(file)
     git.close()
 #
 # Here we just plow through all the files.

contrib/git-stats/gitdm/gitlog.py

@@ -61,7 +61,7 @@ def SaveLine(line):
 def get_header(patch, line, input):
     if line == '':
         if patch.author == '':
-            print 'Funky auth line in', patch.commit
+            print('Funky auth line in', patch.commit)
             patch.author = database.LookupStoreHacker('Unknown',
                                                       'unknown@hacker.net')
         return S_DESC
@@ -78,7 +78,7 @@ def get_header(patch, line, input):
 
 def get_desc(patch, line, input):
     if not line:
-        print 'Missing desc in', patch.commit
+        print('Missing desc in', patch.commit)
         return S_CHANGELOG
     patch.desc = line
     line = getline(input)
@@ -186,7 +186,7 @@ def grabpatch(input):
         return None
     m = patterns['commit'].match(line)
     if not m:
-        print 'noncommit', line
+        print('noncommit', line)
         return None
     p = patch(m.group(1))
     state = S_HEADER
@@ -197,7 +197,7 @@ def grabpatch(input):
         line = getline(input)
         if line is None:
             if state != S_NUMSTAT:
-                print 'Ran out of patch', state
+                print('Ran out of patch', state)
                 return None
             return p
         state = grabbers[state](p, line, input)

contrib/git-stats/gitdm/logparser.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 #-*- coding:utf-8 -*-
 #
 # Copyright © 2009 Germán Póo-Caamaño <gpoo@gnome.org>
@@ -85,6 +85,6 @@ def __grab_patch__(self):
     patches = LogPatchSplitter(sys.stdin)
 
     for patch in patches:
-        print '---------- NEW PATCH ----------'
+        print('---------- NEW PATCH ----------')
         for line in patch:
-            print line,
+            print(line, end=' ')