travis-ci: record and skip successfully built trees
[git/git.git] / ci / lib-travisci.sh
index 197aa14..bade716 100755 (executable)
@@ -21,6 +21,52 @@ skip_branch_tip_with_tag () {
        fi
 }
 
+good_trees_file="$HOME/travis-cache/good-trees"
+
+# Save some info about the current commit's tree, so we can skip the build
+# job if we encounter the same tree again and can provide a useful info
+# message.
+save_good_tree () {
+       echo "$(git rev-parse $TRAVIS_COMMIT^{tree}) $TRAVIS_COMMIT $TRAVIS_JOB_NUMBER $TRAVIS_JOB_ID" >>"$good_trees_file"
+       # limit the file size
+       tail -1000 "$good_trees_file" >"$good_trees_file".tmp
+       mv "$good_trees_file".tmp "$good_trees_file"
+}
+
+# Skip the build job if the same tree has already been built and tested
+# successfully before (e.g. because the branch got rebased, changing only
+# the commit messages).
+skip_good_tree () {
+       if ! good_tree_info="$(grep "^$(git rev-parse $TRAVIS_COMMIT^{tree}) " "$good_trees_file")"
+       then
+               # Haven't seen this tree yet, or no cached good trees file yet.
+               # Continue the build job.
+               return
+       fi
+
+       echo "$good_tree_info" | {
+               read tree prev_good_commit prev_good_job_number prev_good_job_id
+
+               if test "$TRAVIS_JOB_ID" = "$prev_good_job_id"
+               then
+                       cat <<-EOF
+                       $(tput setaf 2)Skipping build job for commit $TRAVIS_COMMIT.$(tput sgr0)
+                       This commit has already been built and tested successfully by this build job.
+                       To force a re-build delete the branch's cache and then hit 'Restart job'.
+                       EOF
+               else
+                       cat <<-EOF
+                       $(tput setaf 2)Skipping build job for commit $TRAVIS_COMMIT.$(tput sgr0)
+                       This commit's tree has already been built and tested successfully in build job $prev_good_job_number for commit $prev_good_commit.
+                       The log of that build job is available at https://travis-ci.org/$TRAVIS_REPO_SLUG/jobs/$prev_good_job_id
+                       To force a re-build delete the branch's cache and then hit 'Restart job'.
+                       EOF
+               fi
+       }
+
+       exit 0
+}
+
 # Set 'exit on error' for all CI scripts to let the caller know that
 # something went wrong.
 # Set tracing executed commands, primarily setting environment variables
@@ -30,6 +76,7 @@ set -ex
 mkdir -p "$HOME/travis-cache"
 
 skip_branch_tip_with_tag
+skip_good_tree
 
 if test -z "$jobname"
 then