trace2: add variable description to git.txt
Documentation/technical/api-trace2.txt contains the full details
of the trace2 API and the GIT_TR2* environment variables. However,
most environment variables are included in Documentation/git.txt,
including the GIT_TRACE* variables.
Add a brief description of the GIT_TR2* variables with links to
the full technical details. The biggest difference from the
original variables is that we can specify a Unix Domain Socket.
Mention this difference, but leave the details to the technical
documents.
Reported-by: Szeder Gábor <szeder.dev@gmail.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/Documentation/git.txt b/Documentation/git.txt
index 6d1f2fd..72adfcc 100644
--- a/Documentation/git.txt
+++ b/Documentation/git.txt
@@ -660,6 +660,27 @@
When a curl trace is enabled (see `GIT_TRACE_CURL` above), do not dump
data (that is, only dump info lines and headers).
+`GIT_TR2`::
+ Enables more detailed trace messages from the "trace2" library.
+ Output from `GIT_TR2` is a simple text-based format for human
+ readability.
++
+The `GIT_TR2` variables can take many values. Any value available to
+the `GIT_TRACE` variables is also available to `GIT_TR2`. The `GIT_TR2`
+variables can also specify a Unix Domain Socket. See
+link:technical/api-trace2.html[Trace2 documentation] for full details.
+
+`GIT_TR2_EVENT`::
+ This setting writes a JSON-based format that is suited for machine
+ interpretation. See link:technical/api-trace2.html[Trace2 documentation]
+ for full details.
+
+`GIT_TR2_PERF`::
+ In addition to the text-based messages available in `GIT_TR2`, this
+ setting writes a column-based format for understanding nesting
+ regions. See link:technical/api-trace2.html[Trace2 documentation]
+ for full details.
+
`GIT_REDACT_COOKIES`::
This can be set to a comma-separated list of strings. When a curl trace
is enabled (see `GIT_TRACE_CURL` above), whenever a "Cookies:" header
