[PATCH v3 0/4] commit-graph: fsck zero/non-zero generation number fixes

Here's a(nother) small reroll of a series that I sent which expanded on a patch that Peff sent earlier in the thread to remove a section of unreachable code that was noticed by Coverity in the `verify_one_commit_graph()` function.

The first few patches are the same, but the fourth (now final) patch is modified to track a single example of a commit with zero and non-zero generation to only emit the warning once at the end of processing.

Thanks as always for your review!

Jeff King (1):
  commit-graph: verify swapped zero/non-zero generation cases

Taylor Blau (3):
  commit-graph: introduce `commit_graph_generation_from_graph()`
  t/t5318-commit-graph.sh: test generation zero transitions during fsck
  commit-graph: commit-graph: avoid repeated mixed generation number
    warnings

 commit-graph.c          | 38 ++++++++++++++++++++++++--------------
 t/t5318-commit-graph.sh | 18 ++++++++++++------
 2 files changed, 36 insertions(+), 20 deletions(-)

Range-diff against v2: 1: a1cc22297e = 1: c88f945a54 commit-graph: introduce `commit_graph_generation_from_graph()` 2: 38b8cd5e9f = 2: 8f8e0b6644 commit-graph: verify swapped zero/non-zero generation cases 3: d14f3ca840 = 3: 34a505dd4b t/t5318-commit-graph.sh: test generation zero transitions during fsck 4: e378fd6f93 < -: ---------- commit-graph: invert negated conditional, extract to function 5: 23bcb7d270 < -: ---------- commit-graph: avoid repeated mixed generation number warnings -: ---------- > 4: 52b49bb434 commit-graph: commit-graph: avoid repeated mixed generation number warnings