[PATCH 2/8] Maintainer-check: warn against zsh xtrace bug

[Stefano Lattarini]

Maintainer-check: warn against zsh xtrace bug.

Extended target maintainer-check, to warn against idioms and
constructs in test scripts which might trigger the Zsh xtrace
bug.

* Makefile.am (sc_tests_stderr_redirection): New check.
(sc_tests_stderr_redirection__perl_code): New internal macro.
(sc_tests_stderr_redirection__whitelist): Likewise.
(syntax_check_rules): Added `sc_tests_stderr_redirection'.

From ec8b0ea72f2423d648e366d76ac192c7307e1411 Mon Sep 17 00:00:00 2001
From: Stefano Lattarini <address@hidden>
Date: Tue, 8 Dec 2009 18:09:14 +0100
Subject: [PATCH 2/8] Maintainer-check: warn against zsh xtrace bug

Extended target maintainer-check, to warn against idioms and
constructs in test scripts which might trigger the Zsh xtrace
bug.

* Makefile.am (sc_tests_stderr_redirection): New check.
(sc_tests_stderr_redirection__perl_code): New internal macro.
(sc_tests_stderr_redirection__whitelist): Likewise.
(syntax_check_rules): Added `sc_tests_stderr_redirection'.
---
 ChangeLog   |   10 +++++++++
 Makefile.am |   66 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 Makefile.in |   44 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 120 insertions(+), 0 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 825e919..0b81e60 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2009-01-31  Stefano Lattarini  <address@hidden>
+
+       Extended target maintainer-check, to warn against idioms and
+       constructs in test scripts which might trigger the Zsh xtrace
+       bug.
+       * Makefile.am (sc_tests_stderr_redirection): New check.
+       (sc_tests_stderr_redirection__perl_code): New internal macro.
+       (sc_tests_stderr_redirection__whitelist): Likewise.
+       (syntax_check_rules): Added `sc_tests_stderr_redirection'.
+
 2010-01-31  Stefano Lattarini  <address@hidden>
 
        Testsuite: avoid Zsh-related problem with `set -x'.
diff --git a/Makefile.am b/Makefile.am
index 08047d2..fc8207a 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -190,6 +190,7 @@ sc_tests_required_after_defs \
 sc_tests_overriding_macros_on_cmdline \
 sc_tests_plain_sleep \
 sc_tests_plain_egrep_fgrep \
+sc_tests_stderr_redirection \
 sc_mkdir_p \
 sc_perl_at_substs \
 sc_unquoted_DESTDIR \
@@ -496,6 +497,71 @@ sc_at_in_texi:
          exit 1; \
        fi
 
+## Helper internal macro, holding a list of `file-name:line-number'
+## couples which are exempted from the checks done by target
+## `sc_tests_stderr_redirection' below.
+sc_tests_stderr_redirection__whitelist = \
+  ccnoco.test:37 \
+  depcomp5.test:24
+
+## Helper internal macro, used in the target `sc_tests_stderr_redirection'
+## below.  Do NOT use single quotes in the definition of this macro (using
+## them in `##' comments is ok, though, as they get stripped by automake).
+sc_tests_stderr_redirection__perl_code = \
+    use strict; \
+    use warnings FATAL => "all"; \
+    $$^W = 1; \
+    my $$e = 0; \
+    ## List of whitelisted `file-name:line-number' couples, for which
+    ## our checks are to be skipped.
+    my @whitelist = qw!$(sc_tests_stderr_redirection__whitelist)!; \
+    my %whitelist = map { $$_ => 1 } @whitelist; \
+    foreach my $$file (@ARGV) { \
+        open(FILE, "<$$file") or die "$$file: cannot open: $$!\n"; \
+        while (<FILE>) { \
+            ## Remove traling newline from current input line.
+            chomp; \
+            if (exists $$whitelist{"$$file:$$."}) { \
+                ## Current line is whitelisted, checks must be skipped
+                print "$@: INFO: skipping whitelisted line $$file:$$.\n"; \
+                next; \
+            }; \
+            ## Save original input line.
+            my $$s = $$_; \
+            ## Normalize format of redirections.
+            s|(>+)\s*|$$1|g; \
+            ## For our purposes, there is no distinction between overriding
+            ## (`> out') and appending (`>> out') redirections.
+            s|>>|>|g; \
+            ## The construct `>/dev/null 2>&1' still redirects stderr to
+            ## /dev/null, so we can safely ignore it.
+            s|>/dev/null\s+2>&1\b||g; \
+            ## Look for bad stderr redirections, and if any is found,
+            ## display the guilty line (with file name and line number),
+            ## and properly update the exit status.
+            if (m|\b2>(?!/dev/null\b)|) { \
+                print "$$file:$$.: $$s\n"; \
+                $$e = 1; \
+            }; \
+        }; \
+        close(FILE) or die "$$file: cannot close: $$!\n"; \
+    }; \
+    exit $$e;
+
+## Redirecting standard error to something != /dev/null might be
+## inappropriate when shell traces are on, due to a bug in Zsh hadling
+## of the xtrace flag.
+sc_tests_stderr_redirection:
+       @cd $(srcdir)/tests || exit 1; \
+        $(PERL) -e '$(sc_tests_stderr_redirection__perl_code)' *.test; \
+        case $$? in \
+         0) exit 0;; \
+         1) echo $@: The previous lines might trigger a Zsh xtrace bug.; \
+            echo $@: Consider using the run_command shell function.;; \
+         *) echo $@: INTERNAL ERROR in auxiliary perl script.;; \
+        esac 1>&2; \
+        exit 1;
+
 
 git-dist: maintainer-check
 ## Make sure the NEWS file is up-to-date.
diff --git a/Makefile.in b/Makefile.in
index e8fb282..0082bde 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -312,12 +312,45 @@ sc_tests_required_after_defs \
 sc_tests_overriding_macros_on_cmdline \
 sc_tests_plain_sleep \
 sc_tests_plain_egrep_fgrep \
+sc_tests_stderr_redirection \
 sc_mkdir_p \
 sc_perl_at_substs \
 sc_unquoted_DESTDIR \
 sc_tabs_in_texi \
 sc_at_in_texi
 
+sc_tests_stderr_redirection__whitelist = \
+  ccnoco.test:37 \
+  depcomp5.test:24
+
+sc_tests_stderr_redirection__perl_code = \
+    use strict; \
+    use warnings FATAL => "all"; \
+    $$^W = 1; \
+    my $$e = 0; \
+    my @whitelist = qw!$(sc_tests_stderr_redirection__whitelist)!; \
+    my %whitelist = map { $$_ => 1 } @whitelist; \
+    foreach my $$file (@ARGV) { \
+        open(FILE, "<$$file") or die "$$file: cannot open: $$!\n"; \
+        while (<FILE>) { \
+            chomp; \
+            if (exists $$whitelist{"$$file:$$."}) { \
+                print "$@: INFO: skipping whitelisted line $$file:$$.\n"; \
+                next; \
+            }; \
+            my $$s = $$_; \
+            s|(>+)\s*|$$1|g; \
+            s|>>|>|g; \
+            s|>/dev/null\s+2>&1\b||g; \
+            if (m|\b2>(?!/dev/null\b)|) { \
+                print "$$file:$$.: $$s\n"; \
+                $$e = 1; \
+            }; \
+        }; \
+        close(FILE) or die "$$file: cannot close: $$!\n"; \
+    }; \
+    exit $$e;
+
 WGET = wget
 WGET_SV_CVS = $(WGET) http://savannah.gnu.org/cgi-bin/viewcvs/~checkout~/
 WGET_SV_GIT_CF = $(WGET) 
'http://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;hb=HEAD;f='
@@ -1210,6 +1243,17 @@ sc_at_in_texi:
          exit 1; \
        fi
 
+sc_tests_stderr_redirection:
+       @cd $(srcdir)/tests || exit 1; \
+        $(PERL) -e '$(sc_tests_stderr_redirection__perl_code)' *.test; \
+        case $$? in \
+         0) exit 0;; \
+         1) echo $@: The previous lines might trigger a Zsh xtrace bug.; \
+            echo $@: Consider using the run_command shell function.;; \
+         *) echo $@: INTERNAL ERROR in auxiliary perl script.;; \
+        esac 1>&2; \
+        exit 1;
+
 git-dist: maintainer-check
        @if sed 1q $(srcdir)/NEWS | grep -e "$(VERSION)" > /dev/null; then :; 
else \
          echo "NEWS not updated; not releasing" 1>&2; \
-- 
1.6.5