[PATCH/RFC 0/2] no-op shell script i18n infrastructure

[PATCH/RFC 0/2] no-op shell script i18n infrastructure

[Ævar Arnfjörð Bjarmason]

While the no-op C patch series is cooking I thought I'd send an RFC
for the no-op shellscript infrastructure. So here (as threatened in
<AANLkTinUtqJJHNyS9CxrC=VnS87v=GH=pOw9yr4r=pii@mail.gmail.com>[1]) is
the infrastructure needed to gettextize the shell script programs.

To quote my previous E-Mail[1] here are the things that are DONE and
still need to be done.
    
    Open issues:
    
       * Write documentation for git-sh-i18n.sh and git-sh-i18n--envsubst
         like we have for git-sh-setup (already in WIP form).

It now has documentation. So this isn't a problem anymore.
    
       * git-sh-i18n--envsubst is still too fat:
    
            $ ldd -r git-sh-i18n--envsubst
                linux-vdso.so.1 =>  (0x00007fffc60fd000)
                libz.so.1 => /usr/lib/libz.so.1 (0x00007f25cff9e000)
                libcrypto.so.0.9.8 => /usr/lib/libcrypto.so.0.9.8
    (0x00007f25cfbfd000)
                libpthread.so.0 => /lib/libpthread.so.0 (0x00007f25cf9e0000)
                libc.so.6 => /lib/libc.so.6 (0x00007f25cf67f000)
                libdl.so.2 => /lib/libdl.so.2 (0x00007f25cf47b000)
                /lib64/ld-linux-x86-64.so.2 (0x00007f25d01c0000)
    
         It only needs to link to libc, but I didn't find out when I last
         checked how to convince the Makefile to only link against
         that. Help welcome :)

This is still an issue. It needs to link to libgit for xmalloc() and
friends, but it doesn't need libz, libcrypto etc.
    
       * Deal with the changes in 92c62a3f4f93432c0c82e3031a9e64e03ba290f7:
    
            $ git --no-pager  grep -A1 abomination *.sh
            git-pull.sh:            # XXX: This is an abomination
            git-pull.sh-            require_clean_work_tree "pull with
    rebase" "Please commit or stash them."
    
         The changes Ramkumar Ramachandra made in 92c62a3f4f, while good,
         are hard to square with i18n.
    
         I think I'll just leave those bits untranslated for now and deal
         with them later, since I'm trying to keep this minimal.

This is not part of this RFC series, but I still haven't dealt with it
in my branch.
    
    And then there's the issue that unlike the C patches these will not be
    a no-op that'll be optimized away by the compiler. We'll be calling an
    external program for displaying messages. While this is a trivial cost
    on Unix (especially in the context we're using it, i.e. not in tight
    loops) it's more expensive on Windows.
    
    I don't see any way to deal with that short of implementing some
    pre-processor, but I think the cost is worth it, but others might
    disagree of course.

This is still a problem I think. Although there's been some work on
this on the MinGW front from what I can gleam from the mailing list.
    
1. http://www.spinics.net/lists/git/msg151971.html

Ævar Arnfjörð Bjarmason (2):
  git-sh-i18n--envsubst: our own envsubst(1) for eval_gettext()
  git-sh-i18n.sh: add no-op gettext() and eval_gettext() wrappers

 .gitignore                              |    3 +
 Documentation/git-sh-i18n--envsubst.txt |   36 +++
 Documentation/git-sh-i18n.txt           |   57 ++++
 Makefile                                |    2 +
 git-sh-i18n.sh                          |   17 ++
 sh-i18n--envsubst.c                     |  444 +++++++++++++++++++++++++++++++
 6 files changed, 559 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/git-sh-i18n--envsubst.txt
 create mode 100644 Documentation/git-sh-i18n.txt
 create mode 100644 git-sh-i18n.sh
 create mode 100644 sh-i18n--envsubst.c

-- 
1.7.4.1

[PATCH/RFC 1/2] git-sh-i18n--envsubst: our own envsubst(1) for eval_gettext()

[Ævar Arnfjörð Bjarmason]

Add a git-sh-i18n--envsubst program which is a stripped-down version
of the GNU envsubst(1) program that comes with GNU gettext for use in
the eval_gettext() fallback, instead of using a clever (but broken)
printf + eval + printf trick.

In a previous incarnation of the gettext series I implemented the
eval_gettext() fallback like this:

    eval_gettext() {
        gettext_out=$(gettext "$1")
        gettext_eval="printf '%s' \"$gettext_out\""
        printf "%s" "`eval \"$gettext_eval\"`"
    }

This was clever, but would incorrectly handle cases where the variable
being interpolated contained spaces. E.g.:

    cmd="git foo"; eval_gettext "command: \$cmd"

Would emit "command: gitfoo", instead of the correct "command: git
foo". This happened with a message in git-am.sh that used the $cmdline
variable.

To work around this, and to improve our variable expansion behavior
(eval has security issues) I've imported a stripped-down version of
gettext's envsubst(1) program. With it eval_gettext() is implemented
like this:

    eval_gettext() {
        printf "%s" "$1" | (
            export PATH $(git sh-i18n--envsubst --variables "$1");
            git sh-i18n--envsubst "$1"
        )
    }

These are the modifications I made to envsubst.c as I turned it into
sh-i18n--envsubst.c:

 * Added our git-compat-util.h header for xrealloc() and friends.

 * Removed inclusion of gettext-specific headers.

 * Removed most of main() and replaced it with my own. The modified
   version only does option parsing for --variables. That's all it
   needs.

 * Modified error() invocations to use our error() instead of
   error(3).

 * Replaced the gettext XNMALLOC(n, size) macro with just
   xmalloc(n). Since XNMALLOC() only allocated char's.

 * Removed the string_list_destroy function. It's redundant (also in
   the upstream code).

 * Replaced the use of stdbool.h (a C99 header) by doing the following
   replacements on the code:

    * s/bool/unsigned short int/g
    * s/true/1/g
    * s/false/0/g

Reported-by: Johannes Sixt <j.sixt@viscovery.net>
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 .gitignore                              |    2 +
 Documentation/git-sh-i18n--envsubst.txt |   36 +++
 Makefile                                |    1 +
 sh-i18n--envsubst.c                     |  444 +++++++++++++++++++++++++++++++
 4 files changed, 483 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/git-sh-i18n--envsubst.txt
 create mode 100644 sh-i18n--envsubst.c

diff --git a/.gitignore b/.gitignore
index c460c66..dad653d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -127,6 +127,8 @@
 /git-rm
 /git-send-email
 /git-send-pack
+/git-sh-i18n
+/git-sh-i18n--envsubst
 /git-sh-setup
 /git-shell
 /git-shortlog
diff --git a/Documentation/git-sh-i18n--envsubst.txt b/Documentation/git-sh-i18n--envsubst.txt
new file mode 100644
index 0000000..e146a2c
--- /dev/null
+++ b/Documentation/git-sh-i18n--envsubst.txt
@@ -0,0 +1,36 @@
+git-sh-i18n--envsubst(1)
+========================
+
+NAME
+----
+git-sh-i18n--envsubst - Git's own envsubst(1) for i18n fallbacks
+
+DESCRIPTION
+-----------
+
+This is not a command the end user would want to run.  Ever.
+This documentation is meant for people who are studying the
+plumbing scripts and/or are writing new ones.
+
+git-sh-i18n--envsubst is Git's stripped-down copy of the GNU
+`envsubst(1)` program that comes with the GNU gettext
+package. It's used internally by linkgit:git-sh-i18n[1] to
+provide the `eval_gettext` fallback on Solaris and systems
+that don't have a gettext implementation.
+
+No promises are made about the interface, or that this
+program won't disappear without warning in the next version
+of Git. Don't use it.
+
+Author
+------
+Written by Ævar Arnfjörð Bjarmason <avarab@gmail.com>
+
+Documentation
+--------------
+Documentation by Ævar Arnfjörð Bjarmason and the git-list
+<git@vger.kernel.org>.
+
+GIT
+---
+Part of the linkgit:git[1] suite
diff --git a/Makefile b/Makefile
index 7497835..c002c08 100644
--- a/Makefile
+++ b/Makefile
@@ -419,6 +419,7 @@ PROGRAM_OBJS += shell.o
 PROGRAM_OBJS += show-index.o
 PROGRAM_OBJS += upload-pack.o
 PROGRAM_OBJS += http-backend.o
+PROGRAM_OBJS += sh-i18n--envsubst.o
 
 PROGRAMS += $(patsubst %.o,git-%$X,$(PROGRAM_OBJS))
 
diff --git a/sh-i18n--envsubst.c b/sh-i18n--envsubst.c
new file mode 100644
index 0000000..8db71b1
--- /dev/null
+++ b/sh-i18n--envsubst.c
@@ -0,0 +1,444 @@
+/*
+ * sh-i18n--envsubst.c - a stripped-down version of gettext's envsubst(1)
+ *
+ * Copyright (C) 2010 Ævar Arnfjörð Bjarmason
+ *
+ * This is a modified version of
+ * 67d0871a8c:gettext-runtime/src/envsubst.c from the gettext.git
+ * repository. It has been stripped down to only implement the
+ * envsubst(1) features that we need in the git-sh-i18n fallbacks.
+ *
+ * The "Close standard error" part in main() is from
+ * 8dac033df0:gnulib-local/lib/closeout.c. The copyright notices for
+ * both files are reproduced immediately below.
+ */
+
+#include "git-compat-util.h"
+
+/* Substitution of environment variables in shell format strings.
+   Copyright (C) 2003-2007 Free Software Foundation, Inc.
+   Written by Bruno Haible <bruno@clisp.org>, 2003.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software Foundation,
+   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+
+/* closeout.c - close standard output and standard error
+   Copyright (C) 1998-2007 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software Foundation,
+   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+
+#include <errno.h>
+#include <getopt.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+/* If true, substitution shall be performed on all variables.  */
+static unsigned short int all_variables;
+
+/* Forward declaration of local functions.  */
+static void print_variables (const char *string);
+static void note_variables (const char *string);
+static void subst_from_stdin (void);
+
+int
+main (int argc, char *argv[])
+{
+  /* Default values for command line options.  */
+  unsigned short int show_variables = 0;
+
+  switch (argc)
+	{
+	case 1:
+	  error ("we won't substitute all variables on stdin for you");
+	  /*
+	  all_variables = 1;
+      subst_from_stdin ();
+	  */
+	case 2:
+	  /* echo '$foo and $bar' | git sh-i18n--envsubst --variables '$foo and $bar' */
+	  all_variables = 0;
+	  note_variables (argv[1]);
+      subst_from_stdin ();
+	  break;
+	case 3:
+	  /* git sh-i18n--envsubst --variables '$foo and $bar' */
+	  if (strcmp(argv[1], "--variables"))
+		error ("first argument must be --variables when two are given");
+	  show_variables = 1;
+      print_variables (argv[2]);
+	  break;
+	default:
+	  error ("too many arguments");
+	  break;
+	}
+
+  /* Close standard error.  This is simpler than fwriteerror_no_ebadf, because
+     upon failure we don't need an errno - all we can do at this point is to
+     set an exit status.  */
+  errno = 0;
+  if (ferror (stderr) || fflush (stderr))
+    { 
+      fclose (stderr);
+      exit (EXIT_FAILURE);
+    }
+  if (fclose (stderr) && errno != EBADF)
+    exit (EXIT_FAILURE);
+
+  exit (EXIT_SUCCESS);
+}
+
+/* Parse the string and invoke the callback each time a $VARIABLE or
+   ${VARIABLE} construct is seen, where VARIABLE is a nonempty sequence
+   of ASCII alphanumeric/underscore characters, starting with an ASCII
+   alphabetic/underscore character.
+   We allow only ASCII characters, to avoid dependencies w.r.t. the current
+   encoding: While "${\xe0}" looks like a variable access in ISO-8859-1
+   encoding, it doesn't look like one in the BIG5, BIG5-HKSCS, GBK, GB18030,
+   SHIFT_JIS, JOHAB encodings, because \xe0\x7d is a single character in these
+   encodings.  */
+static void
+find_variables (const char *string,
+		void (*callback) (const char *var_ptr, size_t var_len))
+{
+  for (; *string != '\0';)
+    if (*string++ == '$')
+      {
+	const char *variable_start;
+	const char *variable_end;
+	unsigned short int valid;
+	char c;
+
+	if (*string == '{')
+	  string++;
+
+	variable_start = string;
+	c = *string;
+	if ((c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z') || c == '_')
+	  {
+	    do
+	      c = *++string;
+	    while ((c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z')
+		   || (c >= '0' && c <= '9') || c == '_');
+	    variable_end = string;
+
+	    if (variable_start[-1] == '{')
+	      {
+		if (*string == '}')
+		  {
+		    string++;
+		    valid = 1;
+		  }
+		else
+		  valid = 0;
+	      }
+	    else
+	      valid = 1;
+
+	    if (valid)
+	      callback (variable_start, variable_end - variable_start);
+	  }
+      }
+}
+
+
+/* Print a variable to stdout, followed by a newline.  */
+static void
+print_variable (const char *var_ptr, size_t var_len)
+{
+  fwrite (var_ptr, var_len, 1, stdout);
+  putchar ('\n');
+}
+
+/* Print the variables contained in STRING to stdout, each one followed by a
+   newline.  */
+static void
+print_variables (const char *string)
+{
+  find_variables (string, &print_variable);
+}
+
+
+/* Type describing list of immutable strings,
+   implemented using a dynamic array.  */
+typedef struct string_list_ty string_list_ty;
+struct string_list_ty
+{
+  const char **item;
+  size_t nitems;
+  size_t nitems_max;
+};
+
+/* Initialize an empty list of strings.  */
+static inline void
+string_list_init (string_list_ty *slp)
+{
+  slp->item = NULL;
+  slp->nitems = 0;
+  slp->nitems_max = 0;
+}
+
+/* Append a single string to the end of a list of strings.  */
+static inline void
+string_list_append (string_list_ty *slp, const char *s)
+{
+  /* Grow the list.  */
+  if (slp->nitems >= slp->nitems_max)
+    {
+      size_t nbytes;
+
+      slp->nitems_max = slp->nitems_max * 2 + 4;
+      nbytes = slp->nitems_max * sizeof (slp->item[0]);
+      slp->item = (const char **) xrealloc (slp->item, nbytes);
+    }
+
+  /* Add the string to the end of the list.  */
+  slp->item[slp->nitems++] = s;
+}
+
+/* Compare two strings given by reference.  */
+static int
+cmp_string (const void *pstr1, const void *pstr2)
+{
+  const char *str1 = *(const char **)pstr1;
+  const char *str2 = *(const char **)pstr2;
+
+  return strcmp (str1, str2);
+}
+
+/* Sort a list of strings.  */
+static inline void
+string_list_sort (string_list_ty *slp)
+{
+  if (slp->nitems > 0)
+    qsort (slp->item, slp->nitems, sizeof (slp->item[0]), cmp_string);
+}
+
+/* Test whether a string list contains a given string.  */
+static inline int
+string_list_member (const string_list_ty *slp, const char *s)
+{
+  size_t j;
+
+  for (j = 0; j < slp->nitems; ++j)
+    if (strcmp (slp->item[j], s) == 0)
+      return 1;
+  return 0;
+}
+
+/* Test whether a sorted string list contains a given string.  */
+static int
+sorted_string_list_member (const string_list_ty *slp, const char *s)
+{
+  size_t j1, j2;
+
+  j1 = 0;
+  j2 = slp->nitems;
+  if (j2 > 0)
+    {
+      /* Binary search.  */
+      while (j2 - j1 > 1)
+	{
+	  /* Here we know that if s is in the list, it is at an index j
+	     with j1 <= j < j2.  */
+	  size_t j = (j1 + j2) >> 1;
+	  int result = strcmp (slp->item[j], s);
+
+	  if (result > 0)
+	    j2 = j;
+	  else if (result == 0)
+	    return 1;
+	  else
+	    j1 = j + 1;
+	}
+      if (j2 > j1)
+	if (strcmp (slp->item[j1], s) == 0)
+	  return 1;
+    }
+  return 0;
+}
+
+
+/* Set of variables on which to perform substitution.
+   Used only if !all_variables.  */
+static string_list_ty variables_set;
+
+/* Adds a variable to variables_set.  */
+static void
+note_variable (const char *var_ptr, size_t var_len)
+{
+  char *string = xmalloc (var_len + 1);
+  memcpy (string, var_ptr, var_len);
+  string[var_len] = '\0';
+
+  string_list_append (&variables_set, string);
+}
+
+/* Stores the variables occurring in the string in variables_set.  */
+static void
+note_variables (const char *string)
+{
+  string_list_init (&variables_set);
+  find_variables (string, &note_variable);
+  string_list_sort (&variables_set);
+}
+
+
+static int
+do_getc ()
+{
+  int c = getc (stdin);
+
+  if (c == EOF)
+    {
+      if (ferror (stdin))
+	error ("error while reading standard input");
+    }
+
+  return c;
+}
+
+static inline void
+do_ungetc (int c)
+{
+  if (c != EOF)
+    ungetc (c, stdin);
+}
+
+/* Copies stdin to stdout, performing substitutions.  */
+static void
+subst_from_stdin ()
+{
+  static char *buffer;
+  static size_t bufmax;
+  static size_t buflen;
+  int c;
+
+  for (;;)
+    {
+      c = do_getc ();
+      if (c == EOF)
+	break;
+      /* Look for $VARIABLE or ${VARIABLE}.  */
+      if (c == '$')
+	{
+	  unsigned short int opening_brace = 0;
+	  unsigned short int closing_brace = 0;
+
+	  c = do_getc ();
+	  if (c == '{')
+	    {
+	      opening_brace = 1;
+	      c = do_getc ();
+	    }
+	  if ((c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z') || c == '_')
+	    {
+	      unsigned short int valid;
+
+	      /* Accumulate the VARIABLE in buffer.  */
+	      buflen = 0;
+	      do
+		{
+		  if (buflen >= bufmax)
+		    {
+		      bufmax = 2 * bufmax + 10;
+		      buffer = xrealloc (buffer, bufmax);
+		    }
+		  buffer[buflen++] = c;
+
+		  c = do_getc ();
+		}
+	      while ((c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z')
+		     || (c >= '0' && c <= '9') || c == '_');
+
+	      if (opening_brace)
+		{
+		  if (c == '}')
+		    {
+		      closing_brace = 1;
+		      valid = 1;
+		    }
+		  else
+		    {
+		      valid = 0;
+		      do_ungetc (c);
+		    }
+		}
+	      else
+		{
+		  valid = 1;
+		  do_ungetc (c);
+		}
+
+	      if (valid)
+		{
+		  /* Terminate the variable in the buffer.  */
+		  if (buflen >= bufmax)
+		    {
+		      bufmax = 2 * bufmax + 10;
+		      buffer = xrealloc (buffer, bufmax);
+		    }
+		  buffer[buflen] = '\0';
+
+		  /* Test whether the variable shall be substituted.  */
+		  if (!all_variables
+		      && !sorted_string_list_member (&variables_set, buffer))
+		    valid = 0;
+		}
+
+	      if (valid)
+		{
+		  /* Substitute the variable's value from the environment.  */
+		  const char *env_value = getenv (buffer);
+
+		  if (env_value != NULL)
+		    fputs (env_value, stdout);
+		}
+	      else
+		{
+		  /* Perform no substitution at all.  Since the buffered input
+		     contains no other '$' than at the start, we can just
+		     output all the buffered contents.  */
+		  putchar ('$');
+		  if (opening_brace)
+		    putchar ('{');
+		  fwrite (buffer, buflen, 1, stdout);
+		  if (closing_brace)
+		    putchar ('}');
+		}
+	    }
+	  else
+	    {
+	      do_ungetc (c);
+	      putchar ('$');
+	      if (opening_brace)
+		putchar ('{');
+	    }
+	}
+      else
+	putchar (c);
+    }
+}
-- 
1.7.4.1

[PATCH/RFC 2/2] git-sh-i18n.sh: add no-op gettext() and eval_gettext() wrappers

[Ævar Arnfjörð Bjarmason]

Add a no-op wrapper library for Git's shell scripts. To split up the
gettext series I'm first submitting patches to gettextize the source
tree before I add any of the Makefile and Shell library changes needed
to actually use them.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---

This documentation doesn't accurately reflect what it does *now*, but
what it'll do eventually later in the series.

 .gitignore                    |    1 +
 Documentation/git-sh-i18n.txt |   57 +++++++++++++++++++++++++++++++++++++++++
 Makefile                      |    1 +
 git-sh-i18n.sh                |   17 ++++++++++++
 4 files changed, 76 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/git-sh-i18n.txt
 create mode 100644 git-sh-i18n.sh

diff --git a/.gitignore b/.gitignore
index dad653d..e9ab0af 100644
--- a/.gitignore
+++ b/.gitignore
@@ -130,6 +130,7 @@
 /git-sh-i18n
 /git-sh-i18n--envsubst
 /git-sh-setup
+/git-sh-i18n
 /git-shell
 /git-shortlog
 /git-show
diff --git a/Documentation/git-sh-i18n.txt b/Documentation/git-sh-i18n.txt
new file mode 100644
index 0000000..b41b3af
--- /dev/null
+++ b/Documentation/git-sh-i18n.txt
@@ -0,0 +1,57 @@
+git-sh-i18n(1)
+==============
+
+NAME
+----
+git-sh-i18n - Git's i18n setup code for shell scripts
+
+SYNOPSIS
+--------
+'. "$(git --exec-path)/git-sh-i18n"'
+
+DESCRIPTION
+-----------
+
+This is not a command the end user would want to run.  Ever.
+This documentation is meant for people who are studying the
+Porcelain-ish scripts and/or are writing new ones.
+
+The 'git sh-i18n scriptlet is designed to be sourced (using
+`.`) by Git's porcelain programs implemented in shell
+script. It provides wrappers for the GNU `gettext` and
+`eval_gettext` functions accessible through the `gettext.sh`
+script, and provides pass-through fallbacks on systems
+without GNU gettext.
+
+FUNCTIONS
+---------
+
+gettext::
+	On GNU systems this will be the `gettext` function from
+	`gettext.sh`, on Solaris it`ll be the `gettext(1)`
+	command.
+
+	If neither of those implementations are available a
+	dummy fall-through function is provided.
+    
+eval_gettext::
+	On GNU systems this will be the `eval_gettext` function
+	from `gettext.sh`, on Solaris we provide an
+	`eval_gettext` using the
+	linkgit:git-sh-i18n--envsubst[1] helper.
+
+	If neither of those implementations are available a
+	dummy fall-through function is provided.
+
+Author
+------
+Written by Ævar Arnfjörð Bjarmason <avarab@gmail.com>
+
+Documentation
+--------------
+Documentation by Ævar Arnfjörð Bjarmason and the git-list
+<git@vger.kernel.org>.
+
+GIT
+---
+Part of the linkgit:git[1] suite
diff --git a/Makefile b/Makefile
index c002c08..f5fa8a6 100644
--- a/Makefile
+++ b/Makefile
@@ -386,6 +386,7 @@ SCRIPT_SH += git-web--browse.sh
 SCRIPT_LIB += git-mergetool--lib
 SCRIPT_LIB += git-parse-remote
 SCRIPT_LIB += git-sh-setup
+SCRIPT_LIB += git-sh-i18n
 
 SCRIPT_PERL += git-add--interactive.perl
 SCRIPT_PERL += git-difftool.perl
diff --git a/git-sh-i18n.sh b/git-sh-i18n.sh
new file mode 100644
index 0000000..ea05e16
--- /dev/null
+++ b/git-sh-i18n.sh
@@ -0,0 +1,17 @@
+#!/bin/sh
+#
+# Copyright (c) 2010 Ævar Arnfjörð Bjarmason
+#
+# This is a skeleton no-op implementation of gettext for Git. It'll be
+# replaced by something that uses gettext.sh in a future patch series.
+
+gettext () {
+	printf "%s" "$1"
+}
+
+eval_gettext () {
+	printf "%s" "$1" | (
+		export PATH $(git sh-i18n--envsubst --variables "$1");
+		git sh-i18n--envsubst "$1"
+	)
+}
-- 
1.7.4.1

Re: [PATCH/RFC 1/2] git-sh-i18n--envsubst: our own envsubst(1) for eval_gettext()

[Ævar Arnfjörð Bjarmason]

On Thu, Mar 3, 2011 at 01:14, Junio C Hamano <gitster@pobox.com> wrote:
> Ævar Arnfjörð Bjarmason  <avarab@gmail.com> writes:
>
>> In a previous incarnation of the gettext series I implemented the
>> eval_gettext() fallback like this:
>>
>>     eval_gettext() {
>>         gettext_out=$(gettext "$1")
>>         gettext_eval="printf '%s' \"$gettext_out\""
>>         printf "%s" "`eval \"$gettext_eval\"`"
>>     }
>>
>> This was clever, but would incorrectly handle cases where the variable
>> being interpolated contained spaces. E.g.:
>>
>>     cmd="git foo"; eval_gettext "command: \$cmd"
>>
>> Would emit "command: gitfoo", instead of the correct "command: git
>> foo".
>
> Hmm, are you sure you got your quoting right?
>
>    $ cat >1.sh <<\EOF
>    #!/bin/sh
>    gettext () {
>            case "$1" in
>            'command: $cmd') echo 'dcomman: $cmd' ;;
>            *) echo "GETTEXT POISON" ;;
>            esac
>    }
>
>    eval_gettext() {
>            gettext_out=$(gettext "$1") &&
>            gettext_eval="printf '%s' \"$gettext_out\"" &&
>            gettext_cmd=$(eval "$gettext_eval") &&
>            printf "%s" "$gettext_cmd"
>    }
>
>    cmd="git foo"
>    eval_gettext "command: \$cmd"
>    EOF
>    $ sh -x 1.sh
>    + cmd='git foo'
>    + eval_gettext 'command: $cmd'
>    ++ gettext 'command: $cmd'
>    ++ case "$1" in
>    ++ echo 'dcomman: $cmd'
>    + gettext_out='dcomman: $cmd'
>    + gettext_eval='printf '\''%s'\'' "dcomman: $cmd"'
>    ++ eval 'printf '\''%s'\'' "dcomman: $cmd"'
>    +++ printf %s 'dcomman: git foo'
>    + gettext_cmd='dcomman: git foo'
>    + printf %s 'dcomman: git foo'
>    dcomman: git foo
>
> Am I grossly missing something from what you are trying to do here?

(CC-ing the list again, so there's a record of this in the mail
archive).

Your eval_gettext() is better, but it still fails in cases where the
string contains "'s. E.g.:

    test_expect_success C_LOCALE_OUTPUT 'eval_gettext: our
eval_gettext() fallback can interpolate variables with spaces in them'
'
        cmdline="git am" &&
        export cmdline;
        printf "When you have resolved this problem run \"git am
--resolved\"." >expect &&
        eval_gettext "When you have resolved this problem run
\"\$cmdline --resolved\"." >actual
        test_cmp expect actual
    '

If this were just:

    test_expect_success C_LOCALE_OUTPUT 'eval_gettext: our
eval_gettext() fallback can interpolate variables with spaces in them'
'
        cmdline="git am" &&
        export cmdline;
        printf "When you have resolved this problem run git am
--resolved." >expect &&
        eval_gettext "When you have resolved this problem run
\$cmdline --resolved." >actual
        test_cmp expect actual
    '

Your version would work.

Maybe there's some portable version of doing this that works with
variables with spaces mixed with quotes. But unless someone can point
it out I'll submit a series with git-sh-i18n--envsubst and tests
demonstrating why it's needed soon.q