[PATCH 0/2] git-p4 support for older python

Offered for consideration.

These two patches allow git-p4 to run on python 2.4 which is shipped on
RHEL 5.X.  The changes are minor and unintrusive in my opinion, but please
feel free to reject one or both of them for any reason (in which case the
version check at the top of git-p4.py should be updated).

Brandon Casey (2):
  git-p4.py: support Python 2.5
  git-p4.py: support Python 2.4

 INSTALL                    |  2 +-
 git-p4.py                  | 30 ++++++++++++++++++++++++++----
 t/t9802-git-p4-filetype.sh | 11 ++++++-----
 3 files changed, 33 insertions(+), 10 deletions(-)

-- 
1.8.1.1.297.gad3d74e


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Python 2.5 and older do not accept None as the first argument to
translate() and complain with:

   TypeError: expected a character buffer object

Satisfy this older python by calling maketrans() to generate an empty
translation table and supplying that to translate().

This allows git-p4 to be used with Python 2.5.

Signed-off-by: Brandon Casey <redacted>
---
 INSTALL   | 2 +-
 git-p4.py | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/INSTALL b/INSTALL
index 28f34bd..fc723b3 100644
--- a/INSTALL
+++ b/INSTALL

@@ -131,7 +131,7 @@ Issues of note:
 	  use English. Under autoconf the configure script will do this
 	  automatically if it can't find libintl on the system.
 
-	- Python version 2.6 or later is needed to use the git-p4
+	- Python version 2.5 or later is needed to use the git-p4
 	  interface to Perforce.
 
  - Some platform specific issues are dealt with Makefile rules,

diff --git a/git-p4.py b/git-p4.py
index 2da5649..4f95d7a 100755
--- a/git-p4.py
+++ b/git-p4.py

@@ -768,7 +768,8 @@ def wildcard_encode(path):
     return path
 
 def wildcard_present(path):
-    return path.translate(None, "*#@%") != path
+    from string import maketrans
+    return path.translate(maketrans("",""), "*#@%") != path
 
 class Command:
     def __init__(self):

-- 
1.8.1.1.297.gad3d74e


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Python 2.4 lacks the following features:

   subprocess.check_call
   struct.pack_into

Take a cue from 460d1026 and provide an implementation of the
CalledProcessError exception.  Then replace the calls to
subproccess.check_call with calls to subprocess.call that check the return
status and raise a CalledProcessError exception if necessary.

The struct.pack_into in t/9802 can be converted into a single struct.pack
call which is available in Python 2.4.

Signed-off-by: Brandon Casey <redacted>
---
 INSTALL                    |  2 +-
 git-p4.py                  | 27 ++++++++++++++++++++++++---
 t/t9802-git-p4-filetype.sh | 11 ++++++-----
 3 files changed, 31 insertions(+), 9 deletions(-)

diff --git a/INSTALL b/INSTALL
index fc723b3..b96e16d 100644
--- a/INSTALL
+++ b/INSTALL

@@ -131,7 +131,7 @@ Issues of note:
 	  use English. Under autoconf the configure script will do this
 	  automatically if it can't find libintl on the system.
 
-	- Python version 2.5 or later is needed to use the git-p4
+	- Python version 2.4 or later is needed to use the git-p4
 	  interface to Perforce.
 
  - Some platform specific issues are dealt with Makefile rules,

diff --git a/git-p4.py b/git-p4.py
index 4f95d7a..faec09d 100755
--- a/git-p4.py
+++ b/git-p4.py

@@ -18,6 +18,21 @@ import optparse, os, marshal, subprocess, shelve
 import tempfile, getopt, os.path, time, platform
 import re, shutil
 
+try:
+    from subprocess import CalledProcessError
+except ImportError:
+    # from python2.7:subprocess.py
+    # Exception classes used by this module.
+    class CalledProcessError(Exception):
+        """This exception is raised when a process run by check_call() returns
+        a non-zero exit status.  The exit status will be stored in the
+        returncode attribute."""
+        def __init__(self, returncode, cmd):
+            self.returncode = returncode
+            self.cmd = cmd
+        def __str__(self):
+            return "Command '%s' returned non-zero exit status %d" % (self.cmd, self.returncode)
+
 verbose = False
 
 # Only labels/tags matching this will be imported/exported

@@ -158,13 +173,17 @@ def system(cmd):
     expand = isinstance(cmd,basestring)
     if verbose:
         sys.stderr.write("executing %s\n" % str(cmd))
-    subprocess.check_call(cmd, shell=expand)
+    retcode = subprocess.call(cmd, shell=expand)
+    if retcode:
+        raise CalledProcessError(retcode, cmd)
 
 def p4_system(cmd):
     """Specifically invoke p4 as the system command. """
     real_cmd = p4_build_cmd(cmd)
     expand = isinstance(real_cmd, basestring)
-    subprocess.check_call(real_cmd, shell=expand)
+    retcode = subprocess.call(real_cmd, shell=expand)
+    if retcode:
+        raise CalledProcessError(retcode, real_cmd)
 
 def p4_integrate(src, dest):
     p4_system(["integrate", "-Dt", wildcard_encode(src), wildcard_encode(dest)])

@@ -3174,7 +3193,9 @@ class P4Clone(P4Sync):
         init_cmd = [ "git", "init" ]
         if self.cloneBare:
             init_cmd.append("--bare")
-        subprocess.check_call(init_cmd)
+        retcode = subprocess.call(init_cmd)
+        if retcode:
+            raise CalledProcessError(retcode, init_cmd)
 
         if not P4Sync.run(self, depotPaths):
             return False

diff --git a/t/t9802-git-p4-filetype.sh b/t/t9802-git-p4-filetype.sh
index 21924df..be299dc 100755
--- a/t/t9802-git-p4-filetype.sh
+++ b/t/t9802-git-p4-filetype.sh

@@ -105,12 +105,13 @@ build_gendouble() {
 	cat >gendouble.py <<-\EOF
 	import sys
 	import struct
-	import array
 
-	s = array.array("c", '\0' * 26)
-	struct.pack_into(">L", s,  0, 0x00051607)  # AppleDouble
-	struct.pack_into(">L", s,  4, 0x00020000)  # version 2
-	s.tofile(sys.stdout)
+	s = struct.pack(">LL18s",
+			0x00051607,  # AppleDouble
+			0x00020000,  # version 2
+			""           # pad to 26 bytes
+	)
+	sys.stdout.write(s);
 	EOF
 }
 

-- 
1.8.1.1.297.gad3d74e


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This email message is for the sole use of the intended recipient(s) and may contain
confidential information.  Any unauthorized review, use, disclosure or distribution
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reply email and destroy all copies of the original message.
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drafnel@gmail.com wrote on Fri, 25 Jan 2013 12:44 -0800:

Python 2.5 and older do not accept None as the first argument to
translate() and complain with:

   TypeError: expected a character buffer object

Satisfy this older python by calling maketrans() to generate an empty
translation table and supplying that to translate().

This allows git-p4 to be used with Python 2.5.

This was a lot easier than I imagined!

 def wildcard_present(path):
-    return path.translate(None, "*#@%") != path
+    from string import maketrans
+    return path.translate(maketrans("",""), "*#@%") != path

translate() was a bit too subtle already.  Could you try
something like this instead?

    m = re.search("[*#@%]", path)
    return m is not None

I think that'll work everywhere and not force people to look
up how translate and maketrans work.

		-- Pete

drafnel@gmail.com wrote on Fri, 25 Jan 2013 12:44 -0800:

Python 2.4 lacks the following features:

   subprocess.check_call
   struct.pack_into

Take a cue from 460d1026 and provide an implementation of the
CalledProcessError exception.  Then replace the calls to
subproccess.check_call with calls to subprocess.call that check the return
status and raise a CalledProcessError exception if necessary.

The struct.pack_into in t/9802 can be converted into a single struct.pack
call which is available in Python 2.4.

Excellent.  Should have used struct.pack() from the get-go.

Acked-by: Pete Wyckoff <redacted>

One stray semicolon.

In terms of maintenance, I'll not run tests with 2.4 or 2.5
myself, but maybe you would be willing to check an RC candidate
each release?

		-- Pete

On Sat, Jan 26, 2013 at 4:45 AM, Pete Wyckoff [off-list ref] wrote:

drafnel@gmail.com wrote on Fri, 25 Jan 2013 12:44 -0800:

quoted

Python 2.5 and older do not accept None as the first argument to
translate() and complain with:

   TypeError: expected a character buffer object

Satisfy this older python by calling maketrans() to generate an empty
translation table and supplying that to translate().

This allows git-p4 to be used with Python 2.5.

This was a lot easier than I imagined!

quoted

 def wildcard_present(path):
-    return path.translate(None, "*#@%") != path
+    from string import maketrans
+    return path.translate(maketrans("",""), "*#@%") != path

translate() was a bit too subtle already.  Could you try
something like this instead?

    m = re.search("[*#@%]", path)
    return m is not None

I think that'll work everywhere and not force people to look
up how translate and maketrans work.

Yes that's simpler and works fine.

-Brandon

On Sat, Jan 26, 2013 at 4:48 AM, Pete Wyckoff [off-list ref] wrote:

drafnel@gmail.com wrote on Fri, 25 Jan 2013 12:44 -0800:

quoted

+     sys.stdout.write(s);

One stray semicolon.

Whoops.  Thanks.

In terms of maintenance, I'll not run tests with 2.4 or 2.5
myself, but maybe you would be willing to check an RC candidate
each release?

Not a problem.  I'm sure it will get run much more often then that.

-Brandon