patman: Suppress empty changelog entries

Patman outputs a line for every edition of the series in every patch,
regardless of whether any changes were made. This can result in many
redundant lines in patch changelogs, especially when a patch did not exist
before a certain revision. For example, the existing behaviour could result
in a changelog of

Changes in v7: None
Changes in v6: None
Changes in v5:
- Make a change

Changes in v4: None

Changes in v3:
- New

Changes in v2: None

With this patch applied and with --no-empty-changes, the same patch would
look like

(no changes since v5)

Changes in v5:
- Make a change

Changes in v3:
- New

This is entirely aesthetic, but I think it reduces clutter, especially for
patches added later on in a series.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

1 files changed, 22 insertions, 0 deletions

diff --git a/tools/patman/README b/tools/patman/README
index f40defb5ba..092122f3db 100644
--- a/tools/patman/README
+++ b/tools/patman/README
@@ -480,6 +480,28 @@ generate patches without any binary contents. You are supposed to include
 a link to a git repository in your "Commit-notes", "Series-notes" or
 "Cover-letter" for maintainers to fetch the original commit.
 
+8. Patches will have no changelog entries for revisions where they did not
+change. For clarity, if there are no changes for this patch in the most
+recent revision of the series, a note will be added. For example, a patch
+with the following tags in the commit
+
+    Series-version: 5
+    Series-changes: 2
+    - Some change
+
+    Series-changes: 4
+    - Another change
+
+would have a changelog of
+
+    (no changes since v4)
+
+    Changes in v4:
+    - Another change
+
+    Changes in v2:
+    - Some change
+
 Other thoughts
 ==============