Fix problem reported by Donn Cave: if VPATH is an absolute path, it

would always be a hit.   Prevent this by only using VPATH if we know
we are in the build directory.

diff --git a/Modules/getpath.c b/Modules/getpath.c
index e2a87bfe4afeb8b6093e15ca750cd6219b7d13c6..d888df263e4b3b41430cd376a6d621f2d53ce421 100644 (file)
--- a/Modules/getpath.c
+++ b/Modules/getpath.c
@@ -209,25 +209,30 @@ search_for_prefix(argv0_path, home)
        int i, n;
        char *vpath;
 
-       /* Check VPATH to see if argv0_path is in the build directory.
-        * Complication: the VPATH passed in is relative to the
-        * Modules build directory and points to the Modules source
-        * directory; we need it relative to the build tree and
-        * pointing to the source tree.  Solution: chop off a leading
-        * ".." (but only if it's there -- it could be an absolute
-        * path) and chop off the final component (assuming it's
-        * "Modules").
-        */
-       vpath = VPATH;
-       if (vpath[0] == '.' && vpath[1] == '.' && vpath[2] == '/')
-               vpath += 3;
+       /* Check to see if argv[0] is in the build directory */
        strcpy(prefix, argv0_path);
-       join(prefix, vpath);
-       reduce(prefix);
-       join(prefix, "Lib");
-       join(prefix, LANDMARK);
-       if (exists(prefix))
-               return -1;
+       join(prefix, "Modules/Setup");
+       if (exists(prefix)) {
+               /* Check VPATH to see if argv0_path is in the build directory.
+                * Complication: the VPATH passed in is relative to the
+                * Modules build directory and points to the Modules source
+                * directory; we need it relative to the build tree and
+                * pointing to the source tree.  Solution: chop off a leading
+                * ".." (but only if it's there -- it could be an absolute
+                * path) and chop off the final component (assuming it's
+                * "Modules").
+                */
+               vpath = VPATH;
+               if (vpath[0] == '.' && vpath[1] == '.' && vpath[2] == '/')
+                       vpath += 3;
+               strcpy(prefix, argv0_path);
+               join(prefix, vpath);
+               reduce(prefix);
+               join(prefix, "Lib");
+               join(prefix, LANDMARK);
+               if (exists(prefix))
+                       return -1;
+       }
 
        if (home) {
                /* Check $PYTHONHOME */
@@ -474,6 +479,8 @@ calculate_path()
                        strcpy(buf, rtpypath);
                        strcat(buf, delimiter);
                }
+               else
+                       buf[0] = '\0';
 
                /* Next goes merge of compile-time $PYTHONPATH with
                 * dynamically located prefix.