checkkconfigsymbols.py: find relevant commits

Add option -f/--find to find relevant commits when using the --diff
option.  --find is useful in case a user wants to check commits that
potentially cause a Kconfig symbol to be missing.  This is done via 'git
log -G $SYMBOL' (i.e., to get a list of commits that change $SYMBOL).
The relevant commits are printed below the "SYMBOL\tFILES" line,
followed by an empty line to increase readability.

Signed-off-by: Valentin Rothberg <valentinrothberg@gmail.com>
Acked-by: Stefan Hengelein <stefan.hengelein@fau.de>
Acked-by: Andreas Ruprecht <andreas.ruprecht@fau.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: vrothberg

scripts/checkkconfigsymbols.py

@@ -58,6 +58,11 @@ def parse_options():
                            "input format bases on Git log's "
                            "\'commmit1..commit2\'.")
 
+    parser.add_option('-f', '--find', dest='find', action='store_true',
+                      default=False,
+                      help="Find and show commits that may cause symbols to be "
+                           "missing.  Required to run with --diff.")
+
     parser.add_option('-i', '--ignore', dest='ignore', action='store',
                       default="",
                       help="Ignore files matching this pattern.  Note that "
@@ -86,6 +91,9 @@ def parse_options():
                      "'--force' if you\nwant to ignore this warning and "
                      "continue.")
 
+    if opts.commit:
+        opts.find = False
+
     if opts.ignore:
         try:
             re.match(opts.ignore, "this/is/just/a/test.c")
@@ -129,12 +137,18 @@ def main():
             if not feature in undefined_a:
                 files = sorted(undefined_b.get(feature))
                 print "%s\t%s" % (feature, ", ".join(files))
+                if opts.find:
+                    commits = find_commits(feature, opts.diff)
+                    print commits
             # check if there are new files that reference the undefined feature
             else:
                 files = sorted(undefined_b.get(feature) -
                                undefined_a.get(feature))
                 if files:
                     print "%s\t%s" % (feature, ", ".join(files))
+                    if opts.find:
+                        commits = find_commits(feature, opts.diff)
+                        print commits
 
         # reset to head
         execute("git reset --hard %s" % head)
@@ -156,6 +170,13 @@ def execute(cmd):
     return stdout
 
 
+def find_commits(symbol, diff):
+    """Find commits changing %symbol in the given range of %diff."""
+    commits = execute("git log --pretty=oneline --abbrev-commit -G %s %s"
+                      % (symbol, diff))
+    return commits
+
+
 def tree_is_dirty():
     """Return true if the current working tree is dirty (i.e., if any file has
     been added, deleted, modified, renamed or copied but not committed)."""