scons: Automatically add a git commit message hook
authorAndreas Sandberg <andreas.sandberg@arm.com>
Sun, 5 Feb 2017 05:00:38 +0000 (05:00 +0000)
committerAndreas Sandberg <andreas.sandberg@arm.com>
Wed, 1 Mar 2017 11:42:39 +0000 (11:42 +0000)
Gerrit requires that all commit messages have a Change-Id tag. This
tag is added automatically by a commit message hook in Git. Include
the default Gerrit commit message hook and add it automatically using
scons to make life easier for everyone.

Change-Id: I1270fbaaadf6ed151bddf14521a38e0c1a02d131
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/2166
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>

SConstruct
ext/git-commit-msg [new file with mode: 0755]

index e728e51fda8df2e7bed3bffd2fe6453267de9f81..d405781d4e4f4dfe1bca471508922ef0eba4f22f 100755 (executable)
@@ -268,10 +268,17 @@ against the gem5 style rules on %s.
 This script will now install the hook in your %s.
 Press enter to continue, or ctrl-c to abort: """
 
-mercurial_style_message = style_message % ("hg commit and qrefresh commands",
-                                           ".hg/hgrc file")
-git_style_message = style_message % ("'git commit'",
-                                     ".git/hooks/ directory")
+mercurial_style_message = """
+You're missing the gem5 style hook, which automatically checks your code
+against the gem5 style rules on hg commit and qrefresh commands.
+This script will now install the hook in your .hg/hgrc file.
+Press enter to continue, or ctrl-c to abort: """
+
+git_style_message = """
+You're missing the gem5 style or commit message hook. These hooks help
+to ensure that your code follows gem5's style rules on git commit.
+This script will now install the hook in your .git/hooks/ directory.
+Press enter to continue, or ctrl-c to abort: """
 
 mercurial_style_upgrade_message = """
 Your Mercurial style hooks are not up-to-date. This script will now
@@ -376,10 +383,34 @@ def install_git_style_hooks():
         return
 
     git_hooks = gitdir.Dir("hooks")
-    git_pre_commit_hook = git_hooks.File("pre-commit")
-    git_style_script = File("util/git-pre-commit.py")
+    def hook_exists(hook_name):
+        hook = git_hooks.File(hook_name)
+        return hook.exists()
+
+    def hook_install(hook_name, script):
+        hook = git_hooks.File(hook_name)
+        if hook.exists():
+            print "Warning: Can't install %s, hook already exists." % hook_name
+            return
+
+        if not git_hooks.exists():
+            mkdir(git_hooks.get_abspath())
+
+        # Use a relative symlink if the hooks live in the source directory
+        if hook.is_under(main.root):
+            script_path = os.path.relpath(
+                script.get_abspath(),
+                hook.Dir(".").get_abspath())
+        else:
+            script_path = script.get_abspath()
 
-    if git_pre_commit_hook.exists():
+        try:
+            os.symlink(script_path, hook.get_abspath())
+        except:
+            print "Error updating git %s hook" % hook_name
+            raise
+
+    if hook_exists("pre-commit") and hook_exists("commit-msg"):
         return
 
     print git_style_message,
@@ -389,22 +420,11 @@ def install_git_style_hooks():
         print "Input exception, exiting scons.\n"
         sys.exit(1)
 
-    if not git_hooks.exists():
-        mkdir(git_hooks.get_abspath())
-
-    # Use a relative symlink if the hooks live in the source directory
-    if git_pre_commit_hook.is_under(main.root):
-        script_path = os.path.relpath(
-            git_style_script.get_abspath(),
-            git_pre_commit_hook.Dir(".").get_abspath())
-    else:
-        script_path = git_style_script.get_abspath()
+    git_style_script = File("util/git-pre-commit.py")
+    git_msg_script = File("ext/git-commit-msg")
 
-    try:
-        os.symlink(script_path, git_pre_commit_hook.get_abspath())
-    except:
-        print "Error updating git pre-commit hook"
-        raise
+    hook_install("pre-commit", git_style_script)
+    hook_install("commit-msg", git_msg_script)
 
 # Try to wire up git to the style hooks
 if not ignore_style and main.root.Entry(".git").exists():
diff --git a/ext/git-commit-msg b/ext/git-commit-msg
new file mode 100755 (executable)
index 0000000..60fe59d
--- /dev/null
@@ -0,0 +1,191 @@
+#!/bin/sh
+# From Gerrit Code Review 2.13.5-2617-gba50ae91fd
+#
+# Part of Gerrit Code Review (https://www.gerritcodereview.com/)
+#
+# Copyright (C) 2009 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+unset GREP_OPTIONS
+
+CHANGE_ID_AFTER="Bug|Depends-On|Issue|Test|Feature|Fixes|Fixed"
+MSG="$1"
+
+# Check for, and add if missing, a unique Change-Id
+#
+add_ChangeId() {
+       clean_message=`sed -e '
+               /^diff --git .*/{
+                       s///
+                       q
+               }
+               /^Signed-off-by:/d
+               /^#/d
+       ' "$MSG" | git stripspace`
+       if test -z "$clean_message"
+       then
+               return
+       fi
+
+       # Do not add Change-Id to temp commits
+       if echo "$clean_message" | head -1 | grep -q '^\(fixup\|squash\)!'
+       then
+               return
+       fi
+
+       if test "false" = "`git config --bool --get gerrit.createChangeId`"
+       then
+               return
+       fi
+
+       # Does Change-Id: already exist? if so, exit (no change).
+       if grep -i '^Change-Id:' "$MSG" >/dev/null
+       then
+               return
+       fi
+
+       id=`_gen_ChangeId`
+       T="$MSG.tmp.$$"
+       AWK=awk
+       if [ -x /usr/xpg4/bin/awk ]; then
+               # Solaris AWK is just too broken
+               AWK=/usr/xpg4/bin/awk
+       fi
+
+       # Get core.commentChar from git config or use default symbol
+       commentChar=`git config --get core.commentChar`
+       commentChar=${commentChar:-#}
+
+       # How this works:
+       # - parse the commit message as (textLine+ blankLine*)*
+       # - assume textLine+ to be a footer until proven otherwise
+       # - exception: the first block is not footer (as it is the title)
+       # - read textLine+ into a variable
+       # - then count blankLines
+       # - once the next textLine appears, print textLine+ blankLine* as these
+       #   aren't footer
+       # - in END, the last textLine+ block is available for footer parsing
+       $AWK '
+       BEGIN {
+               # while we start with the assumption that textLine+
+               # is a footer, the first block is not.
+               isFooter = 0
+               footerComment = 0
+               blankLines = 0
+       }
+
+       # Skip lines starting with commentChar without any spaces before it.
+       /^'"$commentChar"'/ { next }
+
+       # Skip the line starting with the diff command and everything after it,
+       # up to the end of the file, assuming it is only patch data.
+       # If more than one line before the diff was empty, strip all but one.
+       /^diff --git / {
+               blankLines = 0
+               while (getline) { }
+               next
+       }
+
+       # Count blank lines outside footer comments
+       /^$/ && (footerComment == 0) {
+               blankLines++
+               next
+       }
+
+       # Catch footer comment
+       /^\[[a-zA-Z0-9-]+:/ && (isFooter == 1) {
+               footerComment = 1
+       }
+
+       /]$/ && (footerComment == 1) {
+               footerComment = 2
+       }
+
+       # We have a non-blank line after blank lines. Handle this.
+       (blankLines > 0) {
+               print lines
+               for (i = 0; i < blankLines; i++) {
+                       print ""
+               }
+
+               lines = ""
+               blankLines = 0
+               isFooter = 1
+               footerComment = 0
+       }
+
+       # Detect that the current block is not the footer
+       (footerComment == 0) && (!/^\[?[a-zA-Z0-9-]+:/ || /^[a-zA-Z0-9-]+:\/\//) {
+               isFooter = 0
+       }
+
+       {
+               # We need this information about the current last comment line
+               if (footerComment == 2) {
+                       footerComment = 0
+               }
+               if (lines != "") {
+                       lines = lines "\n";
+               }
+               lines = lines $0
+       }
+
+       # Footer handling:
+       # If the last block is considered a footer, splice in the Change-Id at the
+       # right place.
+       # Look for the right place to inject Change-Id by considering
+       # CHANGE_ID_AFTER. Keys listed in it (case insensitive) come first,
+       # then Change-Id, then everything else (eg. Signed-off-by:).
+       #
+       # Otherwise just print the last block, a new line and the Change-Id as a
+       # block of its own.
+       END {
+               unprinted = 1
+               if (isFooter == 0) {
+                       print lines "\n"
+                       lines = ""
+               }
+               changeIdAfter = "^(" tolower("'"$CHANGE_ID_AFTER"'") "):"
+               numlines = split(lines, footer, "\n")
+               for (line = 1; line <= numlines; line++) {
+                       if (unprinted && match(tolower(footer[line]), changeIdAfter) != 1) {
+                               unprinted = 0
+                               print "Change-Id: I'"$id"'"
+                       }
+                       print footer[line]
+               }
+               if (unprinted) {
+                       print "Change-Id: I'"$id"'"
+               }
+       }' "$MSG" > "$T" && mv "$T" "$MSG" || rm -f "$T"
+}
+_gen_ChangeIdInput() {
+       echo "tree `git write-tree`"
+       if parent=`git rev-parse "HEAD^0" 2>/dev/null`
+       then
+               echo "parent $parent"
+       fi
+       echo "author `git var GIT_AUTHOR_IDENT`"
+       echo "committer `git var GIT_COMMITTER_IDENT`"
+       echo
+       printf '%s' "$clean_message"
+}
+_gen_ChangeId() {
+       _gen_ChangeIdInput |
+       git hash-object -t commit --stdin
+}
+
+
+add_ChangeId