merge 8.7: avoid unneeded (but expensive) path normalization for several file subsystem commands and operations;

closes [02d5d65d70adab97] and probably [411f52ed87e313dd49e2]

2 files changed, 23 insertions, 2 deletions

diff --git a/unix/tclUnixChan.c b/unix/tclUnixChan.c
index 693720c..0500147 100644
--- a/unix/tclUnixChan.c
+++ b/unix/tclUnixChan.c
@@ -12,6 +12,7 @@
  */
 
 #include "tclInt.h"	/* Internal definitions for Tcl. */
+#include "tclFileSystem.h"
 #include "tclIO.h"	/* To get Channel type declaration. */
 
 #undef SUPPORTS_TTY
@@ -1771,6 +1772,26 @@ TclpOpenFileChannel(
     native = (const char *)Tcl_FSGetNativePath(pathPtr);
     if (native == NULL) {
 	if (interp != (Tcl_Interp *) NULL) {
+	    /*
+	     * We need this just to ensure we return the correct error messages under
+	     * some circumstances (relative paths only), so because the normalization 
+	     * is very expensive, don't invoke it for native or absolute paths.
+	     * Note: since paths starting with ~ are absolute, it also considers tilde expansion,
+	     * (proper error message of tests *io-40.17 "tilde substitution in open")
+	     */
+	    if (
+		(
+		  (
+		    !TclFSCwdIsNative() &&
+		    (Tcl_FSGetPathType(pathPtr) != TCL_PATH_ABSOLUTE)
+		  ) ||
+		  (*TclGetString(pathPtr) == '~')  /* possible tilde expansion */
+		) &&
+		Tcl_FSGetNormalizedPath(interp, pathPtr) == NULL
+	    ) {
+		return NULL;
+	    }
+
 	    Tcl_AppendResult(interp, "couldn't open \"",
 	    TclGetString(pathPtr), "\": filename is invalid on this platform",
 	    (char *)NULL);
diff --git a/unix/tclUnixFile.c b/unix/tclUnixFile.c
index e91ed41..2b0b5b0 100644
--- a/unix/tclUnixFile.c
+++ b/unix/tclUnixFile.c
@@ -1119,9 +1119,9 @@ TclNativeCreateNativeRep(
     Tcl_Obj *validPathPtr;
     Tcl_Size len;
 
-    if (TclFSCwdIsNative()) {
+    if (TclFSCwdIsNative() || Tcl_FSGetPathType(pathPtr) == TCL_PATH_ABSOLUTE) {
 	/*
-	 * The cwd is native, which means we can use the translated path
+	 * The cwd is native (or path is absolute), use the translated path
 	 * without worrying about normalization (this will also usually be
 	 * shorter so the utf-to-external conversion will be somewhat faster).
 	 */