build-aux/msys-to-w32: always output absolute paths.

1 files changed, 19 insertions, 16 deletions

diff --git a/build-aux/msys-to-w32 b/build-aux/msys-to-w32
index f8c37222889..1f9fda49fff 100755
--- a/build-aux/msys-to-w32
+++ b/build-aux/msys-to-w32
@@ -1,5 +1,5 @@
 #!/bin/bash
-# Convert a MSYS path list to Windows-native format.
+# Convert a MSYS path list to absolute, Windows-native format.
 # Status is zero if successful, nonzero otherwise.
 
 # Copyright (C) 2013-2014 Free Software Foundation, Inc.
@@ -25,20 +25,20 @@ usage="usage: ${me} PATHLIST"
 help="$usage
   or:  ${me} OPTION
 
-Convert a MSYS path list to Windows-native format.
+Convert a MSYS path list to absolute, Windows-native format.
 
 PATHLIST should be a colon-separated list of MSYS paths, which will be
 written to the standard output after performing these transformations:
 
 1. Discard empty paths.
 2. Replace: '\' with '/', '//' with '/' and ':' with ';'.
-3. Translate each path to Windows-native format.
+3. Translate each path to absolute, Windows-native format.
 
-Relative paths or paths starting with '%emacs_dir%' will be passed
-verbatim to the standard output.
+Paths starting with '%emacs_dir%' will be passed verbatim to the
+standard output.
 
-Each non existing absolute path will be translated by looking for its
-deepest existing directory, which will be translated and the remainder
+Each non existing path will be translated by looking for its deepest
+existing directory, which will be translated and the remainder
 appended.
 
 Options:
@@ -81,9 +81,6 @@ do
     if [ "${p:0:11}" = "%emacs_dir%" ]
     then
         w32p=$p
-    elif [ "${p:0:1}" != "/" ]
-    then
-        w32p=$p
     elif [ -d "$p" ]
     then
         w32p=$(cd "$p" && pwd -W)
@@ -95,17 +92,23 @@ do
         p=${p//\/\///}
         p=${p%/}
 
-        p1=$p
+        p1=$p # last candidate tried
         while :
         do
-            p1=${p1%/*}
-            [ -z "$p1" ] && p1="/" && break
-            [ -d "$p1" ] && break
+            p2=${p1%/*} # next candidate to try
+            [ "$p2" = "$p1" ] && {
+                # No more candidates to try
+                echo "Invalid path '$p'." >&2
+                exit 1
+            }
+            [ -z "$p2" ] && p2="/" && break
+            [ -d "$p2" ] && break
+            p1=$p2
         done
 
         # translate the existing part and append the rest
-        w32p=$(cd "${p1}" && pwd -W)
-        remainder=${p#$p1}
+        w32p=$(cd "${p2}" && pwd -W)
+        remainder=${p#$p2}
         w32p+=/${remainder#/}
     fi