[PATCH v2 2/2] githooks.txt: Clarify documentation on reference-transaction hook

From

Patrick Steinhardt <ps@pks.im>

Date

Mar 1, 2021, 09:43 UTC

Message-ID

<55905b8693dd49637d0516ee123405cbfb58b6c6.1614591751.git.ps@pks.im>

In-Reply-To

<c30d41de55b8991a09e1d550e853f582b5394dee.1614232040.git.ps@pks.im>

Signed-off-by: Patrick Steinhardt <ps@pks.im>
---
 Documentation/githooks.txt | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/Documentation/githooks.txt b/Documentation/githooks.txt
index 4dad80052e..b51959ff94 100644
--- a/Documentation/githooks.txt
+++ b/Documentation/githooks.txt
@@ -473,7 +473,8 @@ reference-transaction
 
 This hook is invoked by any Git command that performs reference
 updates. It executes whenever a reference transaction is prepared,
-committed or aborted and may thus get called multiple times.
+committed or aborted and may thus get called multiple times. The hook
+does not cover symbolic references (but that may change in the future).
 
 The hook takes exactly one argument, which is the current state the
 given reference transaction is in:
@@ -492,6 +493,14 @@ receives on standard input a line of the format:
 
   <old-value> SP <new-value> SP <ref-name> LF
 
+where `<old-value>` is the old object name passed into the reference
+transaction, `<new-value>` is the new object name to be stored in the
+ref and `<ref-name>` is the full name of the ref. When force updating
+the reference regardless of its current value or when the reference is
+to be created anew, `<old-value>` is the all-zeroes object name. To
+distinguish these cases, you can inspect the current value of
+`<ref-name>` via `git rev-parse`.
+
 The exit status of the hook is ignored for any state except for the
 "prepared" state. In the "prepared" state, a non-zero exit status will
 cause the transaction to be aborted. The hook will not be called with

-- 
2.30.1