bug#49250: dejagnu 1.6.3 breaks automake 1.16.3 testsuite

[Jacob Bachmeyer]

The Automake tests are using a legacy layout that does not meet a 
long-documented requirement.

The DejaGnu manual has for years (including all available revision 
history) stated that a DejaGnu testsuite is required to be in a 
directory tree named "testsuite" at its root.  Previous versions of 
DejaGnu did not actually care, but this led to an ambiguity that made 
integrating DejaGnu with non-recursive Automake build systems very 
difficult.  This caused significant difficulties with DejaGnu's own 
testsuite, and fixing it was needed to actually run the DejaGnu 
testsuite properly.

The simple fix is to move the DejaGnu testsuites in the Automake test 
cases into "testsuite" directories, but this causes the tests to fail 
with older versions of DejaGnu.  This broken legacy case is deprecated 
in 1.6.3 but still supposed to be supported, even though the manual has 
always said that DejaGnu testsuites are required to be in testsuite/ 
directories.

The code that detects this legacy case was written to match conditions 
observed with DejaGnu's own testsuite, with an older version of Automake 
in use at that time.  As a result, that code branch fails to catch the 
situations in the Automake 1.16.3 testsuite and DejaGnu falls back to a 
"deep legacy" mode in which some features do not work.  One of the 
features that does not work in this mode is limiting testing to a single 
tool at a time; this appears to cause most of the failures.


An experimental patch is attached.



-- Jacob

diff -urN -x '*~' dejagnu-1.6.3/runtest.exp dejagnu-1.6.3-patch/runtest.exp
--- dejagnu-1.6.3/runtest.exp   2021-06-16 21:15:25.000000000 -0500
+++ dejagnu-1.6.3-patch/runtest.exp     2021-06-29 21:41:28.735667904 -0500
@@ -741,7 +741,7 @@
     set testsuitedir $base_dir
     set testbuilddir $base_dir
 } else {
-    if { $testsuitedir eq "testsuite" && $srcdir eq "." && $objdir eq "." } {
+    if { $testsuitedir eq "testsuite" && $testbuilddir eq "testsuite" } {
        # Broken legacy case -- testsuite not actually in testsuite/
        # Produce a warning, but continue.
        send_error "WARNING: testsuite is not in a testsuite/ directory.\n"