merge(3p/git): Merge git subtree at v2.29.2 r/1890

This also bumps the stable nixpkgs to 20.09 as of 2020-11-21, because
there is some breakage in the git build related to the netrc
credentials helper which someone has taken care of in nixpkgs.

The stable channel is not used for anything other than git, so this
should be fine.

Change-Id: I3575a19dab09e1e9556cf8231d717de9890484fb

1 files changed, 15 insertions, 0 deletions

diff --git a/third_party/git/Documentation/config/trace2.txt b/third_party/git/Documentation/config/trace2.txt
index 2edbfb02fe5b..01d3afd8a8b3 100644
--- a/third_party/git/Documentation/config/trace2.txt
+++ b/third_party/git/Documentation/config/trace2.txt
@@ -48,9 +48,24 @@ trace2.configParams::
 	May be overridden by the `GIT_TRACE2_CONFIG_PARAMS` environment
 	variable.  Unset by default.
 
+trace2.envVars::
+	A comma-separated list of "important" environment variables that should
+	be recorded in the trace2 output.  For example,
+	`GIT_HTTP_USER_AGENT,GIT_CONFIG` would cause the trace2 output to
+	contain events listing the overrides for HTTP user agent and the
+	location of the Git configuration file (assuming any are set).  May be
+	overriden by the `GIT_TRACE2_ENV_VARS` environment variable.  Unset by
+	default.
+
 trace2.destinationDebug::
 	Boolean.  When true Git will print error messages when a
 	trace target destination cannot be opened for writing.
 	By default, these errors are suppressed and tracing is
 	silently disabled.  May be overridden by the
 	`GIT_TRACE2_DST_DEBUG` environment variable.
+
+trace2.maxFiles::
+	Integer.  When writing trace files to a target directory, do not
+	write additional traces if we would exceed this many files. Instead,
+	write a sentinel file that will block further tracing to this
+	directory. Defaults to 0, which disables this check.