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hooks/pre-commit: check for cycles in dependencies

We need only to consider newly added dependencies.  For each of these deps we
need to check if there is a path from this dep to the current HEAD.

We use recursive_dep() for this task.  Even if recursive_dep() uses a DFS
traversal it will not run into an endless loop if there would be a cycle,
because recursive_dep() takes .topdeps only from committed trees.  And we
require that the committed dependency graph has no cycles.

Signed-off-by: Bert Wesarg <bert.wesarg@googlemail.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
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1 parent 1fb84a0 commit b7fdc229eb9ffb682057d66ce3d3f12337dc0e96 @bertwesarg bertwesarg committed with Uwe Kleine-König Oct 4, 2010
Showing with 33 additions and 2 deletions.
  1. +33 −2 hooks/pre-commit.sh
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35 hooks/pre-commit.sh
@@ -20,7 +20,8 @@ tg_util
if head_=$(git symbolic-ref -q HEAD); then
case "$head_" in
refs/heads/*)
- git rev-parse -q --verify "refs/top-bases${head_#refs/heads}" >/dev/null || exit 0;;
+ head_="${head_#refs/heads/}"
+ git rev-parse -q --verify "refs/top-bases/$head_" >/dev/null || exit 0;;
*)
exit 0;;
esac
@@ -61,4 +62,34 @@ tree=$(git write-tree) ||
check_topfile "$tree" ".topdeps"
check_topfile "$tree" ".topmsg"
-# TODO: Verify .topdeps for valid branch names and against cycles
+check_cycle_name()
+{
+ [ "$head_" != "$_dep" ] ||
+ die "TopGit dependencies form a cycle: perpetrator is $_name"
+}
+
+# we only need to check newly added deps and for these if a path exists to the
+# current HEAD
+git diff --cached "$root_dir/.topdeps" |
+ awk '
+BEGIN { in_hunk = 0; }
+/^@@ / { in_hunk = 1; }
+/^\+/ { if (in_hunk == 1) printf("%s\n", substr($0, 2)); }
+/^[^@ +-]/ { in_hunk = 0; }
+' |
+ while read newly_added; do
+ # check for self as dep
+ [ "$head_" != "$newly_added" ] ||
+ die "Can't have myself as dep"
+
+ # deps can be non-tgish but we can't run recurse_deps() on them
+ ref_exists "refs/top-bases/$newly_added" ||
+ continue
+
+ # recurse_deps uses dfs but takes the .topdeps from the tree,
+ # therefore no endless loop in the cycle-check
+ no_remotes=1 recurse_deps check_cycle_name "$newly_added"
+ done
+
+
+# TODO: Verify .topdeps for valid branch names

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