[PATCH] git-version-gen: avoid test -z portability glitch

[Eric Blake]

Autoconf warns that there are some broken shells where 'test -z "$x"'
gives 0 exit status if $x is ')'.  Since some of our strings come
from command-line arguments, and since git-version-gen is run on
end-user machines where sh might be broken, we should be robust to
abuse.  Some of the instances replaced here are provably safe,
and could not confuse even broken 'test', but it is easier to
replace all instances of test -[nz].

* build-aux/git-version-gen: Prefer portable test spelling, since
git-version-gen is run on more than just developer machines.

Signed-off-by: Eric Blake <address@hidden>
---
 ChangeLog                 |  6 ++++++
 build-aux/git-version-gen | 16 ++++++++--------
 2 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 622211e..41fc6ac 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2012-12-31  Eric Blake  <address@hidden>
+
+       git-version-gen: avoid test -z portability glitch
+       * build-aux/git-version-gen: Prefer portable test spelling, since
+       git-version-gen is run on more than just developer machines.
+
 2012-12-31  Peter Rosin  <address@hidden>  (tiny change)

        git-version-gen: add --fallback option to use if git is not present
diff --git a/build-aux/git-version-gen b/build-aux/git-version-gen
index 9152baa..891f0b4 100755
--- a/build-aux/git-version-gen
+++ b/build-aux/git-version-gen
@@ -1,6 +1,6 @@
 #!/bin/sh
 # Print a version string.
-scriptversion=2012-12-31.22; # UTC
+scriptversion=2012-12-31.23; # UTC

 # Copyright (C) 2007-2012 Free Software Foundation, Inc.
 #
@@ -107,9 +107,9 @@ while test $# -gt 0; do
       echo "$0: Try '--help' for more information." >&2
       exit 1;;
     *)
-      if test -z "$tarball_version_file"; then
+      if test "x$tarball_version_file" = x; then
         tarball_version_file="$1"
-      elif test -z "$tag_sed_script"; then
+      elif test "x$tag_sed_script" = x; then
         tag_sed_script="$1"
       else
         echo "$0: extra non-option argument '$1'." >&2
@@ -119,7 +119,7 @@ while test $# -gt 0; do
   shift
 done

-if test -z "$tarball_version_file"; then
+if test "x$tarball_version_file" = x; then
     echo "$usage"
     exit 1
 fi
@@ -143,11 +143,11 @@ then
         [0-9]*) ;;
         *) v= ;;
     esac
-    test -z "$v" \
+    test "x$v" = x \
         && echo "$0: WARNING: $tarball_version_file is missing or damaged" 1>&2
 fi

-if test -n "$v"
+if test "x$v" != x
 then
     : # use $v
 # Otherwise, if there is at least one git commit involving the working
@@ -187,7 +187,7 @@ then
     # Remove the "g" in git describe's output string, to save a byte.
     v=`echo "$v" | sed 's/-/./;s/\(.*\)-g/\1-/'`;
     v_from_git=1
-elif test -z "$fallback" || git --version >/dev/null 2>&1; then
+elif test "x$fallback" = x || git --version >/dev/null 2>&1; then
     v=UNKNOWN
 else
     v=$fallback
@@ -198,7 +198,7 @@ v=`echo "$v" |sed "s/^$prefix//"`
 # Test whether to append the "-dirty" suffix only if the version
 # string we're using came from git.  I.e., skip the test if it's "UNKNOWN"
 # or if it came from .tarball-version.
-if test -n "$v_from_git"; then
+if test "x$v_from_git" != x; then
   # Don't declare a version "dirty" merely because a time stamp has changed.
   git update-index --refresh > /dev/null 2>&1

-- 
1.8.0.2