Bug 1660614 - Upgrade sccache to pick up more resilient behavior in…

… the presence of cache read failures r=froydnj

This avoids a set of intermittent issues related to `zstd` decompression failures, which in the absence of these changes break the entire build.

This also requires [updating an environment variable](mozilla/sccache#822), which we do in `client.mk` as well as documentation.

Differential Revision: https://phabricator.services.mozilla.com/D88184

build/docs/sccache-dist.rst

@@ -135,8 +135,12 @@ must read::
 * When attempting to get your client running, the output of ``sccache -s`` should
   be consulted to confirm compilations are being distributed. To receive helpful
   logging from the local daemon in case they aren't, run
-  ``SCCACHE_NO_DAEMON=1 RUST_LOG=sccache=trace path/to/sccache --start-server``
-  in a terminal window separate from your build prior to building.
+  ``SCCACHE_NO_DAEMON=1 SCCACHE_LOG=sccache=trace path/to/sccache --start-server``
+  in a terminal window separate from your build prior to building. *NOTE* use
+  ``RUST_LOG`` instead of ``SCCACHE_LOG`` if your build of ``sccache`` does not
+  include `pull request 822
+  <https://github.com/mozilla/sccache/pull/822>`_. (``sccache`` binaries from
+  ``mach bootstrap`` do include this PR.)
 
 * Run ``./mach build -j<value>`` with an appropriately large ``<value>``.
   ``sccache --dist-status`` should provide the number of cores available to you
@@ -179,9 +183,12 @@ similar.
 
   Extra logging may be helpful when setting up a server. To enable logging,
   run your server with
-  ``sudo env RUST_LOG=sccache=trace ~/.mozbuild/sccache/sccache-dist server --config ~/.config/sccache/server.conf``
+  ``sudo env SCCACHE_LOG=sccache=trace ~/.mozbuild/sccache/sccache-dist server --config ~/.config/sccache/server.conf``
   (or similar). *NOTE* ``sudo`` *must* come before setting environment variables
-  for this to work.
+  for this to work. *NOTE* use ``RUST_LOG`` instead of ``SCCACHE_LOG`` if your
+  build of ``sccache`` does not include `pull request 822
+  <https://github.com/mozilla/sccache/pull/822>`_. (``sccache`` binaries from
+  ``mach bootstrap`` do include this PR.)
 
   As when configuring a client, the scheduler url to use is:
   ``https://sccache1.corpdmz.<OFFICE>.mozilla.com``, where <OFFICE> is an

client.mk

@@ -83,7 +83,7 @@ build::
 	# from make (but don't use the + prefix when make -n is used, so that
 	# the command doesn't run in that case)
 	mkdir -p $(UPLOAD_PATH)
-	$(if $(findstring n,$(filter-out --%, $(MAKEFLAGS))),,+)env RUST_LOG=sccache=debug SCCACHE_ERROR_LOG=$(UPLOAD_PATH)/sccache.log $(MOZBUILD_MANAGE_SCCACHE_DAEMON) --start-server
+	$(if $(findstring n,$(filter-out --%, $(MAKEFLAGS))),,+)env SCCACHE_LOG=sccache=debug SCCACHE_ERROR_LOG=$(UPLOAD_PATH)/sccache.log $(MOZBUILD_MANAGE_SCCACHE_DAEMON) --start-server
 endif
 
 ####################################

taskcluster/ci/fetch/toolchains.yml

@@ -352,7 +352,7 @@ sccache:
         type: git
         repo: https://github.com/mozilla/sccache
         # 0.2.13 release + various changes
-        revision: d172e77c1bfd08714e71fe80f80cc149eeae1749
+        revision: 030c80a15e0b1aba0e61df264b320a21bb21fb15
 
 fxc2:
     description: fxc2 source code