[PATCH v2 0/5] commit-graph: fsck zero/non-zero generation number fixes

[Taylor Blau <me@ttaylorr.com>]

Here's a 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.

Everything is the same in the first three patches. The fourth patch is
slightly modified to (in addition to flipping the conditional) extract
the mixed zero/non-zero generation number checks out to its own
function.

The fifth patch is new, and avoids repeatedly warning about mixed
generation numbers by treating `generation_zero` as a bitfield.

Thanks as always for your review!

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

Taylor Blau (4):
  commit-graph: introduce `commit_graph_generation_from_graph()`
  t/t5318-commit-graph.sh: test generation zero transitions during fsck
  commit-graph: invert negated conditional, extract to function
  commit-graph: avoid repeated mixed generation number warnings

 commit-graph.c          | 48 ++++++++++++++++++++++++++++++++---------
 t/t5318-commit-graph.sh | 32 +++++++++++++++++++++------
 2 files changed, 64 insertions(+), 16 deletions(-)

Range-diff against v1:
1:  6ea610f7d2 < -:  ---------- commit-graph: invert negated conditional
-:  ---------- > 1:  701c198e19 commit-graph: introduce `commit_graph_generation_from_graph()`
-:  ---------- > 2:  9b9483893c commit-graph: verify swapped zero/non-zero generation cases
-:  ---------- > 3:  8679db3d0e t/t5318-commit-graph.sh: test generation zero transitions during fsck
-:  ---------- > 4:  32b5d69ebe commit-graph: invert negated conditional, extract to function
-:  ---------- > 5:  b82b15ebc8 commit-graph: avoid repeated mixed generation number warnings
-- 
2.42.0.rc0.30.gb82b15ebc8