msys2-runtime: fix Git's t3701-add-interactive

This reverts the problematic commit that causes a hang when `git add -p` has `cat.exe` configured as a diff filter, and that diff filter is fed input larger than the pipe's buffer size. This fixes git-for-windows/git#4422. Signed-off-by: Johannes Schindelin <[email protected]>
dscho · May 16, 2023 · d81a17c · d81a17c
1 parent 87dab81
commit d81a17c
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diff --git a/msys2-runtime/0061-Revert-Cygwin-pipe-Restore-blocking-mode-for-cygwin-.patch b/msys2-runtime/0061-Revert-Cygwin-pipe-Restore-blocking-mode-for-cygwin-.patch
@@ -0,0 +1,62 @@
+From 0e357e24075b2e8b66c9772bf56d3db6203f88fa Mon Sep 17 00:00:00 2001
+From: Johannes Schindelin <[email protected]>
+Date: Tue, 16 May 2023 12:43:51 +0200
+Subject: [PATCH 61/N] Revert "Cygwin: pipe: Restore blocking mode for cygwin
+ process at startup."
+
+When Git for Windows upgraded its MSYS2 runtime from v3.3.* to v3.4.* at
+long last, the t3701-add-interactive test of Git's test suite started to
+hang consistently, timing out.
+
+The culprit is a `git add -p` call that wants to read from a diff
+filter. This diff filter is `cat.exe`, i.e. nothing special, but that
+diff filter gets input that is larger than the pipe buffer, and
+therefore must not block. Yet that is exactly what it does.
+
+This was a regression that introduced by upgrading from MSYS2 runtime
+v3.3.*. After a tedious, multi-day bisection session, the commit
+introducing that regression was identified as 90788821b7 (Cygwin: pipe:
+Restore blocking mode for cygwin process at startup., 2021-11-17), which
+we hereby revert.
+
+So what bug does this reversion reintroduce?
+
+The commit seems to have been in response to
+https://inbox.sourceware.org/cygwin/CAEv6GOB8PXHgHoz7hdJy6Bia2GWEmUDnTd252gTGinz2vuv=hA@mail.gmail.com/
+which reported a bug when a C# program writes 0-byte content to a Cygwin
+pipe. (Irony of ironies, this report originated from Git's realm, over
+at https://github.com/git-ecosystem/git-credential-manager/issues/509.)
+
+The analysis revealed, back in December '21, that a `CYGWIN=pipe_byte`
+would work around the bug, too, but that did not fix the regression in
+Git's test suite.
+
+That leaves us with the somewhat unsatisfying conclusion that we _might_
+reintroduce a regression when Git Credential Manager tries to talk to an
+_MSYS_ `git.exe`. But since we do not need that in Git for Windows, and
+since we need to have CI builds that do not time out after 6h causing
+failures, it is better to revert that commit, and in the hopefully
+unlikely event that this causes _other_ problems in Git for Windows'
+ecosystem, we will simply have to revisit this issue in more depth.
+
+This fixes https://github.com/git-for-windows/git/issues/4422.
+
+Signed-off-by: Johannes Schindelin <[email protected]>
+---
+ winsup/cygwin/dtable.cc | 3 ---
+ 1 file changed, 3 deletions(-)
+
+diff --git a/winsup/cygwin/dtable.cc b/winsup/cygwin/dtable.cc
+index f90465d..ce1bbbe 100644
+--- a/winsup/cygwin/dtable.cc
++++ b/winsup/cygwin/dtable.cc
+@@ -410,9 +410,6 @@ dtable::init_std_file_from_handle (int fd, HANDLE handle)
+ 	{
+ 	  fhandler_pipe *fhp = (fhandler_pipe *) fh;
+ 	  fhp->set_pipe_buf_size ();
+-	  /* Set read pipe always to nonblocking */
+-	  fhp->set_pipe_non_blocking (fhp->get_device () == FH_PIPER ?
+-				      true : fhp->is_nonblocking ());
+ 	}
+
+       if (!fh->open_setup (openflags))
diff --git a/msys2-runtime/PKGBUILD b/msys2-runtime/PKGBUILD
@@ -4,7 +4,7 @@
 pkgbase=msys2-runtime
 pkgname=('msys2-runtime' 'msys2-runtime-devel')
 pkgver=3.4.6
-pkgrel=1
+pkgrel=2
 pkgdesc="Cygwin POSIX emulation engine"
 arch=('x86_64')
 url="https://www.cygwin.com/"
@@ -86,9 +86,10 @@ source=('msys2-runtime'::git+https://github.com/cygwin/cygwin#tag=cygwin-${pkgve
         0057-Use-MB_CUR_MAX-6-by-default.patch
         0058-Change-the-default-base-address-for-x86_64.patch
         0059-Avoid-sharing-cygheaps-across-Cygwin-versions.patch
-        0060-uname-report-msys2-runtime-commit-hash-too.patch)
+        0060-uname-report-msys2-runtime-commit-hash-too.patch
+        0061-Revert-Cygwin-pipe-Restore-blocking-mode-for-cygwin-.patch)
 sha256sums=('SKIP'
-            '67751e4d22f6e80eedde68c7d63fcbc4b8d43a6f61728ea4105908d7e8787a3a'
+            '0dd8039cc7b85e5a97038090d7a602f4accc617644588f5efb93a36e349d8242'
             'e061d933f7ec1a6ba5a8c56cbdb9e796e3df266409893afba33d9f4f5365f000'
             '52f3b36d3e420374b75af3502afb971279b70828a88fe05870fe35ccab90e2f0'
             'd1526bdea50b470fbbf5a6d5d5d7814a1bed7940d380e140153c290ead320979'
@@ -148,7 +149,8 @@ sha256sums=('SKIP'
             '0dd0b9dc3d24e6556c5f6c758a3157405ae2a75b3760fab92acc3b183151bb50'
             '6e6c217266559b46cd41e60b6cbe8f87a6166c7ea51d8c07241974c504c9ec15'
             '7512fc55bbb0bc6c111ce05aa90269eb4423de8092a063be4009404967b1c6bd'
-            '77f4b172f0e3aee99e1c2da966efffa2e5440ef91e8374a53c488923baac1751')
+            '77f4b172f0e3aee99e1c2da966efffa2e5440ef91e8374a53c488923baac1751'
+            'c82378cdce57d224069bb3a84db2c4582449ab61f487b41cf5bef70219d5fddb')
 
 # Helper macros to help make tasks easier #
 apply_patch_with_msg() {

diff --git a/msys2-runtime/msys2-runtime.commit b/msys2-runtime/msys2-runtime.commit
@@ -1 +1 @@
-82f0d822f7e5ed5b4c5f335bc014a6404f7036f1
+0e357e24075b2e8b66c9772bf56d3db6203f88fa
Original file line number	Diff line number	Diff line change
		@@ -1 +1 @@
		82f0d822f7e5ed5b4c5f335bc014a6404f7036f1
		0e357e24075b2e8b66c9772bf56d3db6203f88fa