@@ -120,6 +120,8 @@ PyAPI_FUNC(const char *) Py_GetBuildInfo(void);
 PyAPI_FUNC(const char *) _Py_svnversion(void);
 PyAPI_FUNC(const char *) Py_SubversionRevision(void);
 PyAPI_FUNC(const char *) Py_SubversionShortBranch(void);
+PyAPI_FUNC(const char *) _Py_hgidentifier(void);
+PyAPI_FUNC(const char *) _Py_hgversion(void);
 
 /* Internal -- various one-time initializations */
 PyAPI_FUNC(PyObject *) _PyBuiltin_Init(void);
 
@@ -35,6 +35,9 @@ LINKCC=		@LINKCC@
 AR=		@AR@
 RANLIB=		@RANLIB@
 SVNVERSION=	@SVNVERSION@
+HGVERSION=	@HGVERSION@
+HGTAG=		@HGTAG@
+HGBRANCH=	@HGBRANCH@
 
 GNULD=		@GNULD@
 
@@ -525,7 +528,12 @@ Modules/getbuildinfo.o: $(PARSER_OBJS) \
 		$(SIGNAL_OBJS) \
 		$(MODOBJS) \
 		$(srcdir)/Modules/getbuildinfo.c
-	$(CC) -c $(PY_CFLAGS) -DSVNVERSION="\"`LC_ALL=C $(SVNVERSION)`\"" -o $@ $(srcdir)/Modules/getbuildinfo.c
+	$(CC) -c $(PY_CFLAGS) \
+	      -DSVNVERSION="\"`LC_ALL=C $(SVNVERSION)`\"" \
+	      -DHGVERSION="\"`LC_ALL=C $(HGVERSION)`\"" \
+	      -DHGTAG="\"`LC_ALL=C $(HGTAG)`\"" \
+	      -DHGBRANCH="\"`LC_ALL=C $(HGBRANCH)`\"" \
+	      -o $@ $(srcdir)/Modules/getbuildinfo.c
 
 Modules/getpath.o: $(srcdir)/Modules/getpath.c Makefile
 	$(CC) -c $(PY_CFLAGS) -DPYTHONPATH='"$(PYTHONPATH)"' \
 
@@ -28,15 +28,28 @@
 #define SVNVERSION "$WCRANGE$$WCMODS?M:$"
 #endif
 
+/* XXX Only unix build process has been tested */
+#ifndef HGVERSION
+#define HGVERSION ""
+#endif
+#ifndef HGTAG
+#define HGTAG ""
+#endif
+#ifndef HGBRANCH
+#define HGBRANCH ""
+#endif
+
 const char *
 Py_GetBuildInfo(void)
 {
     static char buildinfo[50];
-    const char *revision = Py_SubversionRevision();
+    const char *revision = _Py_hgversion();
     const char *sep = *revision ? ":" : "";
-    const char *branch = Py_SubversionShortBranch();
+    const char *hgid = _Py_hgidentifier();
+    if (!(*hgid))
+        hgid = "default";
     PyOS_snprintf(buildinfo, sizeof(buildinfo),
-                  "%s%s%s, %.20s, %.9s", branch, sep, revision,
+                  "%s%s%s, %.20s, %.9s", hgid, sep, revision,
                   DATE, TIME);
     return buildinfo;
 }
@@ -50,3 +63,21 @@ _Py_svnversion(void)
         return svnversion; /* it was interpolated, or passed on command line */
     return "Unversioned directory";
 }
+
+const char *
+_Py_hgversion(void)
+{
+    return HGVERSION;
+}
+
+const char *
+_Py_hgidentifier(void)
+{
+    const char *hgtag, *hgid;
+    hgtag = HGTAG;
+    if ((*hgtag) && strcmp(hgtag, "tip") != 0)
+        hgid = hgtag;
+    else
+        hgid = HGBRANCH;
+    return hgid;
+}
@@ -1358,6 +1358,9 @@ _PySys_Init(void)
     SET_SYS_FROM_STRING("subversion",
                         Py_BuildValue("(UUU)", "CPython", branch,
                                       svn_revision));
+    SET_SYS_FROM_STRING("_mercurial",
+                        Py_BuildValue("(szz)", "CPython", _Py_hgidentifier(),
+                                      _Py_hgversion()));
     SET_SYS_FROM_STRING("dont_write_bytecode",
                          PyBool_FromLong(Py_DontWriteBytecodeFlag));
     SET_SYS_FROM_STRING("api_version",
 
@@ -1,5 +1,5 @@
 #! /bin/sh
-# From configure.in Revision: 88561 .
+# From configure.in Revision.
 # Guess values for system-dependent variables and create Makefiles.
 # Generated by GNU Autoconf 2.68 for python 3.1.
 #
@@ -639,6 +639,10 @@ LN
 INSTALL_DATA
 INSTALL_SCRIPT
 INSTALL_PROGRAM
+HAS_HG
+HGBRANCH
+HGTAG
+HGVERSION
 SVNVERSION
 ARFLAGS
 AR
@@ -5089,6 +5093,58 @@ else
 	SVNVERSION="echo Unversioned directory"
 fi
 
+
+
+
+# Extract the first word of "hg", so it can be a program name with args.
+set dummy hg; ac_word=$2
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+$as_echo_n "checking for $ac_word... " >&6; }
+if ${ac_cv_prog_HAS_HG+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -n "$HAS_HG"; then
+  ac_cv_prog_HAS_HG="$HAS_HG" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if { test -f "$as_dir/$ac_word$ac_exec_ext" && $as_test_x "$as_dir/$ac_word$ac_exec_ext"; }; then
+    ac_cv_prog_HAS_HG="found"
+    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+  test -z "$ac_cv_prog_HAS_HG" && ac_cv_prog_HAS_HG="not-found"
+fi
+fi
+HAS_HG=$ac_cv_prog_HAS_HG
+if test -n "$HAS_HG"; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $HAS_HG" >&5
+$as_echo "$HAS_HG" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+
+if test $HAS_HG = found
+then
+    HGVERSION="hg id -i \$(srcdir)"
+    HGTAG="hg id -t \$(srcdir)"
+    HGBRANCH="hg id -b \$(srcdir)"
+else
+    HGVERSION=""
+    HGTAG=""
+    HGBRANCH=""
+fi
+
 case $MACHDEP in
 bsdos*|hp*|HP*)
 	# install -d does not work on BSDI or HP-UX
 
@@ -785,6 +785,21 @@ else
 	SVNVERSION="echo Unversioned directory"
 fi
 
+AC_SUBST(HGVERSION)
+AC_SUBST(HGTAG)
+AC_SUBST(HGBRANCH)
+AC_CHECK_PROG(HAS_HG, hg, found, not-found)
+if test $HAS_HG = found
+then
+    HGVERSION="hg id -i \$(srcdir)"
+    HGTAG="hg id -t \$(srcdir)"
+    HGBRANCH="hg id -b \$(srcdir)"
+else
+    HGVERSION=""
+    HGTAG=""
+    HGBRANCH=""
+fi
+
 case $MACHDEP in
 bsdos*|hp*|HP*)
 	# install -d does not work on BSDI or HP-UX