Have commit-msg report commit failure

[gnu-emacs] / build-aux / git-hooks / commit-msg

diff --git a/build-aux/git-hooks/commit-msg b/build-aux/git-hooks/commit-msg
index 6a09eddf88bd1cc2bc5dd59a2bcf11fa69d51ecd..6721d53a582363930c05ab30ecd4ad4edd9f2021 100755 (executable)
--- a/build-aux/git-hooks/commit-msg
+++ b/build-aux/git-hooks/commit-msg
@@ -1,7 +1,7 @@
 #!/bin/sh
 # Check the format of GNU Emacs change log entries.
 
-# Copyright 2014 Free Software Foundation, Inc.
+# Copyright 2014-2015 Free Software Foundation, Inc.
 
 # This file is part of GNU Emacs.
 
@@ -20,71 +20,110 @@
 
 # Written by Paul Eggert.
 
+# Prefer gawk if available, as it handles NUL bytes properly.
+if type gawk >/dev/null 2>&1; then
+  awk=gawk
+else
+  awk=awk
+fi
+
 # Use a UTF-8 locale if available, so that the UTF-8 check works.
 # Use U+00A2 CENT SIGN to test whether the locale works.
 cent_sign_utf8_octal='\302\242'
 at_sign=`
   printf "${cent_sign_utf8_octal}@" |
-  awk '{print substr($0, 2)}' 2>/dev/null
+  $awk '{print substr($0, 2)}' 2>/dev/null
 `
 if test "$at_sign" != @; then
   at_sign=`
     printf "${cent_sign_utf8_octal}@" |
-    LC_ALL=en_US.utf8 awk '{print substr($0, 2)}' 2>/dev/null
+    LC_ALL=en_US.UTF-8 $awk '{print substr($0, 2)}' 2>/dev/null
   `
   if test "$at_sign" = @; then
-    LC_ALL=en_US.utf8; export LC_ALL
+    LC_ALL=en_US.UTF-8; export LC_ALL
   fi
 fi
 
 # Check the log entry.
-exec awk '
+exec $awk '
+  BEGIN {
+    if (" " ~ /[[:space:]]/) {
+      space = "[[:space:]]"
+      non_space = "[^[:space:]]"
+      non_print = "[^[:print:]]"
+    } else {
+      # mawk 1.3.3 does not support POSIX bracket expressions.
+      # Approximate them as best we can.
+      space = "[ \f\n\r\t\v]"
+      non_space = "[^ \f\n\r\t\v]"
+      non_print = "[\1-\37\177]"
+    }
+  }
+
   /^#/ { next }
 
   !/^.*$/ {
-    print "Invalid character (not UTF-8)"
+    print "Invalid character (not UTF-8) in commit message"
     status = 1
   }
 
-  nlines == 0 && !/[^[:space:]]/ { next }
+  nlines == 0 && $0 !~ non_space { next }
 
   { nlines++ }
 
-  nlines == 1 && /^[[:space:]]/ {
-    print "White space at start of first line"
-    status = 1
+  nlines == 1 {
+    # Ignore special markers used by "git rebase --autosquash".
+    if (! sub(/^fixup! /, ""))
+      sub(/^squash! /, "")
+
+    if ($0 ~ "^" space) {
+      print "White space at start of commit message'\''s first line"
+      status = 1
+    }
   }
 
-  nlines == 2 && /[^[:space:]]/ {
-    print "Nonempty second line"
+  nlines == 2 && $0 ~ non_space {
+    print "Nonempty second line in commit message"
     status = 1
   }
 
-  /[[:cntrl:]]/ {
-    print "Text contains control character; please use spaces instead of tabs"
-    status = 1
+  {
+    # Expand tabs to spaces for length calculations etc.
+    while (match($0, /\t/)) {
+      before_tab = substr($0, 1, RSTART - 1)
+      after_tab = substr($0, RSTART + 1)
+      $0 = sprintf("%s%*s%s", before_tab, 8 - (RSTART - 1) % 8, "", after_tab)
+    }
   }
 
-  72 < length && /[[:space:]]/ {
-    print "Line longer than 72 characters"
+  78 < length && $0 ~ space {
+    print "Line longer than 78 characters in commit message"
     status = 1
   }
 
   140 < length {
-    print "Word longer than 140 characters"
+    print "Word longer than 140 characters in commit message"
     status = 1
   }
 
   /^Signed-off-by: / {
-    print "'Signed-off-by:' present"
+    print "'\''Signed-off-by:'\'' in commit message"
+    status = 1
+  }
+
+  $0 ~ non_print {
+    print "Unprintable character in commit message"
     status = 1
   }
 
   END {
     if (nlines == 0) {
-      print "Empty change log entry"
+      print "Empty commit message"
       status = 1
     }
+    if (status != 0) {
+      print "Commit aborted; please see the file 'CONTRIBUTE'"
+    }
     exit status
   }
 ' <"$1"