# [PATCH 0/1] Proactively fix a test issue with v3.x of the MSYS2 runtime 5 messages from 2019-05-07 to 2019-05-08. Participants: Johannes Schindelin via GitGitGadget, Eric Sunshine, Junio C Hamano. Thread: https://gitlist.dev/t/51048 ## Johannes Schindelin via GitGitGadget, 2019-05-07 21:51 Subject: [PATCH 0/1] Proactively fix a test issue with v3.x of the MSYS2 runtime Message-ID: URL: https://gitlist.dev/e/pull.185.git.gitgitgadget%40gmail.com ``` I saw this in one of my builds that followed the bleeding edge of Git for Windows' SDK: git.exe has a different idea of the test script's PID than the test script itself. Yet another of the quirks Git for Windows has to deal with... Johannes Schindelin (1): t6500(mingw): use the Windows PID of the shell t/t6500-gc.sh | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) base-commit: 8104ec994ea3849a968b4667d072fedd1e688642 Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-185%2Fdscho%2Ft6500-and-msys2-runtime-v3.x-v1 Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-185/dscho/t6500-and-msys2-runtime-v3.x-v1 Pull-Request: https://github.com/gitgitgadget/git/pull/185 -- gitgitgadget ``` ## Johannes Schindelin via GitGitGadget, 2019-05-07 21:51 Subject: [PATCH 1/1] t6500(mingw): use the Windows PID of the shell Message-ID: URL: https://gitlist.dev/e/ba78a47b873c5f044cbfb147b30a801cc90fb0ac.1557265888.git.gitgitgadget%40gmail.com In-Reply-To: ``` From: Johannes Schindelin In Git for Windows, we use the MSYS2 Bash which inherits a non-standard PID model from Cygwin's POSIX emulation layer: every MSYS2 process has a regular Windows PID, and in addition it has an MSYS2 PID (which corresponds to a shadow process that emulates Unix-style signal handling). With the upgrade to the MSYS2 runtime v3.x, this shadow process cannot be accessed via `OpenProcess()` any longer, and therefore t6500 thought incorrectly that the process referenced in `gc.pid` (which is not actually a real `gc` process in this context, but the current shell) no longer exists. Let's fix this by making sure that the Windows PID is written into `gc.pid` in this test script soo that `git.exe` is able to understand that that process does indeed still exist. Signed-off-by: Johannes Schindelin --- t/t6500-gc.sh | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/t/t6500-gc.sh b/t/t6500-gc.sh index 4684d06552..53258d45a1 100755 --- a/t/t6500-gc.sh +++ b/t/t6500-gc.sh @@ -162,7 +162,15 @@ test_expect_success 'background auto gc respects lock for all operations' ' # now fake a concurrent gc that holds the lock; we can use our # shell pid so that it looks valid. hostname=$(hostname || echo unknown) && - printf "$$ %s" "$hostname" >.git/gc.pid && + shell_pid=$$ && + if test_have_prereq MINGW && test -f /proc/$shell_pid/winpid + then + # In Git for Windows, Bash (actually, the MSYS2 runtime) has a + # different idea of PIDs than git.exe (actually Windows). Use + # the Windows PID in this case. + shell_pid=$(cat /proc/$shell_pid/winpid) + fi && + printf "%d %s" "$shell_pid" "$hostname" >.git/gc.pid && # our gc should exit zero without doing anything run_and_wait_for_auto_gc && -- gitgitgadget ``` ## Eric Sunshine, 2019-05-07 22:25 Subject: Re: [PATCH 1/1] t6500(mingw): use the Windows PID of the shell Message-ID: URL: https://gitlist.dev/e/CAPig%2BcQG4%2BA%2BG%2Bi%2B8RqpDAY2PveULVJ5iNR4HYEUPAd_4Ub04w%40mail.gmail.com In-Reply-To: ``` On Tue, May 7, 2019 at 5:51 PM Johannes Schindelin via GitGitGadget wrote: > [...] > Let's fix this by making sure that the Windows PID is written into > `gc.pid` in this test script soo that `git.exe` is able to understand > that that process does indeed still exist. > > Signed-off-by: Johannes Schindelin > --- > @@ -162,7 +162,15 @@ test_expect_success 'background auto gc respects lock for all operations' ' > + shell_pid=$$ && > + if test_have_prereq MINGW && test -f /proc/$shell_pid/winpid > + then > + # In Git for Windows, Bash (actually, the MSYS2 runtime) has a > + # different idea of PIDs than git.exe (actually Windows). Use > + # the Windows PID in this case. > + shell_pid=$(cat /proc/$shell_pid/winpid) > + fi && > + printf "%d %s" "$shell_pid" "$hostname" >.git/gc.pid && I wonder if it would make sense to abstract this away behind a shell function named shell_pid() which can be specialized for MINGW, much like the shell function pwd() is specialized on Windows. ``` ## Junio C Hamano, 2019-05-08 03:53 Subject: Re: [PATCH 1/1] t6500(mingw): use the Windows PID of the shell Message-ID: URL: https://gitlist.dev/e/xmqqef59iou2.fsf%40gitster-ct.c.googlers.com In-Reply-To: ``` Eric Sunshine writes: > On Tue, May 7, 2019 at 5:51 PM Johannes Schindelin via GitGitGadget > wrote: >> [...] >> Let's fix this by making sure that the Windows PID is written into >> `gc.pid` in this test script soo that `git.exe` is able to understand >> that that process does indeed still exist. >> >> Signed-off-by: Johannes Schindelin >> --- >> @@ -162,7 +162,15 @@ test_expect_success 'background auto gc respects lock for all operations' ' >> + shell_pid=$$ && >> + if test_have_prereq MINGW && test -f /proc/$shell_pid/winpid >> + then >> + # In Git for Windows, Bash (actually, the MSYS2 runtime) has a >> + # different idea of PIDs than git.exe (actually Windows). Use >> + # the Windows PID in this case. >> + shell_pid=$(cat /proc/$shell_pid/winpid) >> + fi && >> + printf "%d %s" "$shell_pid" "$hostname" >.git/gc.pid && > > I wonder if it would make sense to abstract this away behind a shell > function named shell_pid() which can be specialized for MINGW, much > like the shell function pwd() is specialized on Windows. It would be, especially when we need the next such invocation. I'd find it easier to follow if it were if test_have_prereq ... then shell_pid=$(cat /proc/$$/winpid) else shell_pid=$$ fi && ... simply because in each of the cases the mental burden gets smaller (those trying to see what happens on MINGW do not have to recall shell_pid was originally taken from $$ after seeing 'then'; others do not have to wonder if lack of 'else' to cover the platforms they are reading for is deliberate and shell_pid is the only thing expected out of the if/then/fi construct) And I would suggest doing such a rewrite when it becomes a helper shell function, but what is written here is good enough until then, I would think. ``` ## Junio C Hamano, 2019-05-08 06:18 Subject: Re: [PATCH 1/1] t6500(mingw): use the Windows PID of the shell Message-ID: URL: https://gitlist.dev/e/xmqqr299h3ji.fsf%40gitster-ct.c.googlers.com In-Reply-To: ``` Junio C Hamano writes: > Eric Sunshine writes: > >> On Tue, May 7, 2019 at 5:51 PM Johannes Schindelin via GitGitGadget >> wrote: >>> [...] >>> Let's fix this by making sure that the Windows PID is written into >>> `gc.pid` in this test script soo that `git.exe` is able to understand I amended s/soo/so/ while queuing; I did not make any other changes, as I described why in the message I am responding to. Thanks. ```