Add patch tag infrastructure

This change add patch 'tags', eg 'Acked-by' / 'Reviewed-by', etc., to
patchwork.

Tag parsing is implemented in the patch parser's extract_tags function,
which returns a Counter object of the tags in a comment. These are
stored in the PatchTag (keyed to Tag) objects associated with each
patch.

We need to ensure that the main patch lists do not cause per-patch
queries on the Patch.tags ManyToManyField (this would result in ~500
queries per page), so we introduce a new QuerySet (and Manager) for
Patch, adding a with_tag_counts() method to populate the tag counts in a
single query.

As users may be migrating from previous patchwork versions (ie, with no
tag counts in the database), we add a 'retag' management command.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>

1 files changed, 19 insertions, 0 deletions

diff --git a/lib/sql/migration/015-add-patch-tags.sql b/lib/sql/migration/015-add-patch-tags.sql
new file mode 100644
index 0000000..bdf7330
--- /dev/null
+++ b/lib/sql/migration/015-add-patch-tags.sql
@@ -0,0 +1,19 @@
+BEGIN;
+ALTER TABLE patchwork_project ADD COLUMN use_tags boolean default true;
+
+CREATE TABLE "patchwork_tag" (
+    "id" serial NOT NULL PRIMARY KEY,
+    "name" varchar(20) NOT NULL,
+    "pattern" varchar(50) NOT NULL,
+    "abbrev" varchar(2) NOT NULL UNIQUE
+);
+
+CREATE TABLE "patchwork_patchtag" (
+    "id" serial NOT NULL PRIMARY KEY,
+    "patch_id" integer NOT NULL,
+    "tag_id" integer NOT NULL REFERENCES "patchwork_tag" ("id"),
+    "count" integer NOT NULL,
+    UNIQUE ("patch_id", "tag_id")
+);
+
+COMMIT;