[PATCH v2 2/2] t9300: work around partial read bug in Dash v0.5.13
- From
Patrick Steinhardt <ps@pks.im>
- Date
- Apr 2, 2026, 06:51 UTC
- Message-ID
- <20260402-pks-tests-with-dash-v2-2-cd7ab11dabc0@pks.im>
- In-Reply-To
- <20260402-pks-tests-with-dash-v2-0-cd7ab11dabc0@pks.im>
When executing t9300 with Dash v0.5.13.1 we can see that the test hangs completely with the following (condensed) trace:
git fast-import + error=1 + read output + cat input + echo checkpoint + echo progress checkpoint + test rogress checkpoint = progress checkpoint + test rogress checkpoint = UNEXPECTED + echo cruft: rogress checkpoint cruft: rogress checkpoint + read output + test = progress checkpoint + test = UNEXPECTED + echo cruft: cruft: + read output
Basically, what's happening here is that we spawn git-fast-import(1) and wait for it to output a certain string, "progress checkpoint". Curiously though, what we end up reading is "rogress checkpoint" -- so the first byte of the expected string is missing.
Same as in the preceding commit, this seems to be a bug in Dash itself that bisects to c5bf970 (expand: Add multi-byte support to pmatch, 2024-06-02). But other than in the preceding commit, this bug has already been fixed upstream in 079059a (input: Fix heap-buffer-overflow in preadbuffer on long lines, 2026-02-11), which is part of v0.5.13.2.
For now though, work around the bug by waiting for the expected output in a different way. There is no good reason why one version should work better than the other, but at least the new version doesn't exhibit the bug. And, if you ask me, it's also slightly easier to read.
Signed-off-by: Patrick Steinhardt <ps@pks.im> --- t/t9300-fast-import.sh | 32 ++++++++++++++------------------ 1 file changed, 14 insertions(+), 18 deletions(-)
diff --git a/t/t9300-fast-import.sh b/t/t9300-fast-import.sh index 5685cce6fe..479437760b 100755 --- a/t/t9300-fast-import.sh +++ b/t/t9300-fast-import.sh @@ -3635,25 +3635,21 @@ background_import_then_checkpoint () { echo "progress checkpoint" ) >&8 & - error=1 ;# assume the worst - while read output <&9 - do - if test "$output" = "progress checkpoint" - then - error=0 - break - elif test "$output" = "UNEXPECTED" - then - break - fi - # otherwise ignore cruft - echo >&2 "cruft: $output" - done + last=$( + while read output <&9 + do + if test "$output" = "progress checkpoint" || test "$output" = "UNEXPECTED" + then + echo "$output" + break + else + # otherwise ignore cruft + echo >&2 "cruft: $output" + fi + done + ) - if test $error -eq 1 - then - false - fi + test "$last" = "progress checkpoint" } background_import_still_running () {
-- 2.53.0.1323.g189a785ab5.dirty