Pre pop cargo home cache (#512)

* debug (CI): putting reports in artifacts [skip ci]

* debug (CI): remove unneded jobs, revert lated

* change (doc): fix artifacts

* change (CI): CARGO_HOME goes to branch level to avoid collapses; pre-population for it

* change (CI): small fix to codecov

* change (CI): DRY prepop script

* change (CI): DRY prepop script

* change (CI): docstring for pre-pop cache script

* change (CI): no cache for codecov report

.gitlab-ci.yml

@@ -15,7 +15,7 @@ variables:
   GIT_STRATEGY:                    fetch
   GIT_DEPTH:                       100
   CARGO_INCREMENTAL:               0
-  CARGO_HOME:                      "/ci-cache/${CI_PROJECT_NAME}/cargo/${CI_JOB_NAME}"
+  CARGO_HOME:                      "/ci-cache/${CI_PROJECT_NAME}/cargo/${CI_COMMIT_REF_NAME}/${CI_JOB_NAME}"
   CARGO_TARGET_DIR:                "/ci-cache/${CI_PROJECT_NAME}/targets/${CI_COMMIT_REF_NAME}/${CI_JOB_NAME}"
   ALL_CRATES:                      "env storage storage/derive allocator prelude primitives lang lang/macro lang/ir"
 
@@ -125,15 +125,18 @@ codecov:
     # The `cargo-taurpalin` coverage reporting tool seems to have better code instrumentation and thus
     # produces better results for Rust codebases in general. However, unlike `grcov` it requires
     # running docker with `--security-opt seccomp=unconfined` which is why we use `grcov` instead.
-    # We removed the `-Cinline-threshold=0` flag from the above `RUSTFLAGS` since it was bugged
-    # at the time and lead to inlining of functions that shouldn't be inlined for the coverage
-    # report. (More information here: https://github.com/Kogia-sima/rust-covfix/issues/2)
-  script:
-    # RUSTFLAGS are the cause target cache can't be used here
+  before_script:
+    - cargo -vV
+    - rustc -vV
+    - rustup show
+    - bash --version
     - unset "CARGO_TARGET_DIR"
+    - unset "CARGO_HOME"
     - cargo clean
-    - cargo test --verbose --all-features --no-fail-fast --workspace
+  script:
+    # RUSTFLAGS are the cause target cache can't be used here
     - cargo build --verbose --all-features --workspace
+    - cargo test --verbose --all-features --no-fail-fast --workspace
     # coverage with branches
     - grcov ./target -s . -t lcov --llvm --branch --ignore-not-existing --ignore "/*" --ignore "tests/*" -o lcov-w-branch.info
     - rust-covfix -o lcov-w-branch.info lcov-w-branch.info

scripts/pre_cache.sh

@@ -5,16 +5,27 @@ set -u
 # if there is no directory for this $CI_COMMIT_REF_NAME/$CI_JOB_NAME
 # create such directory and
 # copy recursively all the files from the newest dir which has $CI_JOB_NAME, if it exists
-if [[ ! -d $CARGO_TARGET_DIR ]]; then
-  mkdir -p "/ci-cache/$CI_PROJECT_NAME/targets/$CI_COMMIT_REF_NAME";
-  FRESH_CACHE=$(find "/ci-cache/$CI_PROJECT_NAME/targets" -mindepth 2 -maxdepth 2 \
+
+# caches are in /ci-cache/${CI_PROJECT_NAME}/${2}/${CI_COMMIT_REF_NAME}/${CI_JOB_NAME}
+
+function prepopulate {
+  if [[ ! -d $1 ]]; then
+    mkdir -p "/ci-cache/$CI_PROJECT_NAME/$2/$CI_COMMIT_REF_NAME";
+    FRESH_CACHE=$(find "/ci-cache/$CI_PROJECT_NAME/$2" -mindepth 2 -maxdepth 2 \
       -type d -name "$CI_JOB_NAME"  -exec stat --printf="%Y\t%n\n" {} \; |sort -n -r |head -1 |cut -f2);
     if [[ -d $FRESH_CACHE ]]; then
       echo "____Using" "$FRESH_CACHE" "to prepopulate the cache____";
-    time cp -r "$FRESH_CACHE" "$CARGO_TARGET_DIR";
+      time cp -r "$FRESH_CACHE" "$1";
     else
-    echo "_____No such targets dir, proceeding from scratch_____";
+      echo "_____No such $2 dir, proceeding from scratch_____";
     fi
-else
-  echo "____No need to prepopulate CARGO_TARGET_DIR cache____";
-fi
+  else
+    echo "____No need to prepopulate $2 cache____";
+  fi
+}
+
+# CARGO_HOME cache was moved to the same "project/cache_type/branch_name/job_name" level as
+# CARGO_TARGET_DIR because of frequent weird data-race issues. This just means that the same cache that 
+# would have been used for the entire pipeline will be duplicated for the each job.
+prepopulate "$CARGO_HOME" cargo
+prepopulate "$CARGO_TARGET_DIR" targets