[PATCH v2 0/2] fetch: make submodule fetch errors configurable

From: Paulius Zaleckas <paulius.zaleckas@gmail.com>

When fetching with --recurse-submodules, git currently exits with a non-zero status if any submodule references an OID that is not reachable from the submodule's remote. This situation arises naturally when an upstream branch is still in preparation (e.g. a topic branch in a merge window): the local branch does not depend on the missing commit, so a hard failure is unnecessarily disruptive.

Patch 1 fixes a pre-existing NEEDSWORK in submodule.c where a phase-1 fetch failure was recorded immediately, even when a phase-2 OID-based retry was about to be scheduled. After this fix the existing fatal behaviour is preserved but the logic is now structured so that errors are only recorded when the phase-2 retry actually fails.

Patch 2 introduces fetch.submoduleErrors (fail|warn) and --submodule-errors=(fail|warn) to let users opt into non-fatal behaviour. The default remains fail for full backwards compatibility.

Changes in v2:
- Fix option synopsis to use (fail|warn) instead of <fail|warn>
- Add --submodule-errors documentation to Documentation/fetch-options.adoc

Paulius Zaleckas (2):
  submodule: fix premature failure in recursive submodule fetch
  fetch: add fetch.submoduleErrors to make submodule fetch errors
    non-fatal

 Documentation/config/fetch.adoc  | 14 +++++
 Documentation/fetch-options.adoc |  8 +++
 builtin/fetch.c                  | 39 ++++++++++++-
 submodule.c                      | 52 ++++++++++++-----
 submodule.h                      |  7 ++-
 t/t5526-fetch-submodules.sh      | 96 ++++++++++++++++++++++++++++++++
 6 files changed, 200 insertions(+), 16 deletions(-)