prompt: fix missing file errors in zsh

zsh seems to have a bug while redirecting the stderr of the 'read'
command:

% read foo 2>/dev/null <foo
zsh: no such file or directory: foo

Which causes errors to be displayed when certain files are missing.
Let's add a convenience function to manually check if the file is
readable before calling "read".

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/contrib/completion/git-prompt.sh b/contrib/completion/git-prompt.sh
index 7b732d2aeba0e3bca3b42d28f2f8f5730a08ccee..54489080f8ae25a4483cd4bae076942f47f53031 100644 (file)
--- a/contrib/completion/git-prompt.sh
+++ b/contrib/completion/git-prompt.sh
@@ -259,6 +259,13 @@ __git_ps1_colorize_gitstring ()
        r="$c_clear$r"
 }
 
+eread ()
+{
+       f="$1"
+       shift
+       test -r "$f" && read "$@" <"$f"
+}
+
 # __git_ps1 accepts 0 or 1 arguments (i.e., format string)
 # when called from PS1 using command substitution
 # in this mode it prints text to add to bash PS1 prompt (includes branch name)
@@ -321,9 +328,9 @@ __git_ps1 ()
        local step=""
        local total=""
        if [ -d "$g/rebase-merge" ]; then
-               read b 2>/dev/null <"$g/rebase-merge/head-name"
-               read step 2>/dev/null <"$g/rebase-merge/msgnum"
-               read total 2>/dev/null <"$g/rebase-merge/end"
+               eread "$g/rebase-merge/head-name" b
+               eread "$g/rebase-merge/msgnum" step
+               eread "$g/rebase-merge/end" total
                if [ -f "$g/rebase-merge/interactive" ]; then
                        r="|REBASE-i"
                else
@@ -331,10 +338,10 @@ __git_ps1 ()
                fi
        else
                if [ -d "$g/rebase-apply" ]; then
-                       read step 2>/dev/null <"$g/rebase-apply/next"
-                       read total 2>/dev/null <"$g/rebase-apply/last"
+                       eread "$g/rebase-apply/next" step
+                       eread "$g/rebase-apply/last" total
                        if [ -f "$g/rebase-apply/rebasing" ]; then
-                               read b 2>/dev/null <"$g/rebase-apply/head-name"
+                               eread "$g/rebase-apply/head-name" b
                                r="|REBASE"
                        elif [ -f "$g/rebase-apply/applying" ]; then
                                r="|AM"
@@ -358,7 +365,7 @@ __git_ps1 ()
                        b="$(git symbolic-ref HEAD 2>/dev/null)"
                else
                        local head=""
-                       if ! read head 2>/dev/null <"$g/HEAD"; then
+                       if ! eread "$g/HEAD" head; then
                                if [ $pcmode = yes ]; then
                                        PS1="$ps1pc_start$ps1pc_end"
                                fi