[PATCH 2/4] maintainer-scripts/gcc_release: create index between snapshots <-> commits

[Sam James <sam@gentoo.org>]

Create and maintain a known_snapshots.txt index with space-separated format
BRANCH-DATE COMMIT.

For example:
8-20210107 5114ee0676e432493ada968e34071f02fb08114f
8-20210114 f9267925c648f2ccd9e4680b699e581003125bcf
...

This is helpful for bisects and quickly looking up the information from bug
reports.

maintainer-scripts/
	* gcc_release: Create known_snapshots.txt as an index between snapshots
	and commits.

Signed-off-by: Sam James <sam@gentoo.org>
---
Note that there's a few different approaches we can take here. I've gone
for the simpler one of having it still fetch from the remote site and parse
because it's obviously hard for me to test a part which runs on the remote
machine.

We can skip this patch for now if desired. I have mixed feelings about complicating
the contrib/generate_snapshot_index.py script to take an URL / path as I'd ideally
like it to still be easily usable locally.

We could have it be generated locally and then uploaded as well, as another option.

 maintainer-scripts/gcc_release | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/maintainer-scripts/gcc_release b/maintainer-scripts/gcc_release
index 962b8efe99a7..4cd1fa799660 100755
--- a/maintainer-scripts/gcc_release
+++ b/maintainer-scripts/gcc_release
@@ -448,6 +448,9 @@ announce_snapshot() {
   SNAPSHOT_INDEX=${RELEASE}/index.html
 
   changedir "${SNAPSHOTS_DIR}"
+  # Create an index if it doesn't already exist and populate it before we add
+  # the new snapshot.
+  ${PYTHON} ${SOURCE_DIRECTORY}/contrib/generate_snapshot_index.py || error "Failed to generate snapshot index"
   echo \
 "Snapshot gcc-"${RELEASE}" is now available on
   https://gcc.gnu.org/pub/gcc/snapshots/"${RELEASE}"/
@@ -514,6 +517,9 @@ Last modified "${TEXT_DATE}"
   rm -f LATEST-${BRANCH}
   ln -s ${RELEASE} LATEST-${BRANCH}
 
+  # Add the snapshot we just made to the index
+  printf "${RELEASE} ${GITREV}\n" >> known_snapshots.txt
+
   inform "Sending mail"
 
   export QMAILHOST=gcc.gnu.org
@@ -617,6 +623,7 @@ GZIP="${GZIP:-gzip --best}"
 SCP="${SCP:-scp -p}"
 SSH="${SSH:-ssh}"
 TAR="${TAR:-tar}"
+PYTHON="${PYTHON:-python3}"
 
 ########################################################################
 # Command Line Processing
-- 
2.42.0