Merge branch 'sg/trace2-rename'

Rename environment variables that are used to control the "trace2"
mechanism to a more readable name.

* sg/trace2-rename:
  trace2: document the supported values of GIT_TRACE2* env variables
  trace2: rename environment variables to GIT_TRACE2*

1 files changed, 40 insertions, 13 deletions

diff --git a/Documentation/git.txt b/Documentation/git.txt
index 72adfcc5e2..6ddc1e2ca6 100644
--- a/Documentation/git.txt
+++ b/Documentation/git.txt
@@ -660,26 +660,53 @@ of clones and fetches.
 	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`::
+`GIT_TRACE2`::
 	Enables more detailed trace messages from the "trace2" library.
-	Output from `GIT_TR2` is a simple text-based format for human
+	Output from `GIT_TRACE2` 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.
+If this variable is set to "1", "2" or "true" (comparison
+is case insensitive), trace messages will be printed to
+stderr.
++
+If the variable is set to an integer value greater than 2
+and lower than 10 (strictly) then Git will interpret this
+value as an open file descriptor and will try to write the
+trace messages into this file descriptor.
++
+Alternatively, if the variable is set to an absolute path
+(starting with a '/' character), Git will interpret this
+as a file path and will try to append the trace messages
+to it.  If the path already exists and is a directory, the
+trace messages will be written to files (one per process)
+in that directory, named according to the last component
+of the SID and an optional counter (to avoid filename
+collisions).
++
+In addition, if the variable is set to
+`af_unix:[<socket_type>:]<absolute-pathname>`, Git will try
+to open the path as a Unix Domain Socket.  The socket type
+can be either `stream` or `dgram`.
++
+Unsetting the variable, or setting it to empty, "0" or
+"false" (case insensitive) disables trace messages.
++
+See link:technical/api-trace2.html[Trace2 documentation]
+for full details.
+
 
-`GIT_TR2_EVENT`::
+`GIT_TRACE2_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.
+	interpretation.
+	See `GIT_TRACE2` for available trace output options and
+	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
+`GIT_TRACE2_PERF`::
+	In addition to the text-based messages available in `GIT_TRACE2`, this
 	setting writes a column-based format for understanding nesting
-	regions. See link:technical/api-trace2.html[Trace2 documentation]
-	for full details.
+	regions.
+	See `GIT_TRACE2` for available trace output options and
+	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