Am 10/16/2012 8:39, schrieb Johannes Sixt:
> Am 10/15/2012 18:54, schrieb Junio C Hamano:
>> Ideally, that earlier workaround
>> should have done a logica equivalent of:
>> ...
>> and did so not in-line at the calling site but in a compat/ wrapper
>> for fflush() to eliminate the need for the ifdef.
>
> Fair enough.
>
>>> But reverting the EINVAL check from write_or_die.c is out of question,
>>> because that handles a real case.
>
> Correction: I can't reproduce the error messages that this was working
> around anymore in a brief test. I'll revert the check locally and see what
> happens.
The error is reproducible with this command on Windows:
$ git rev-list HEAD | sed 1q
42b333d8bb8709dfc5783dd4c44bdb6012c2c17d
fatal: write failure on 'stdout': Invalid argument
Let's do as you suggested.
--- 8< ---
From: Johannes Sixt <j6t@xxxxxxxx>
Subject: [PATCH] maybe_flush_or_die: move a too-loose Windows specific error
check to compat
Commit b2f5e268 (Windows: Work around an oddity when a pipe with no reader
is written to) introduced a check for EINVAL after fflush() to fight
spurious "Invalid argument" errors on Windows when a pipe was broken. But
this check may hide real errors on systems that do not have the this odd
behavior. Introduce an fflush wrapper in compat/mingw.* so that the treatment
is only applied on Windows.
Signed-off-by: Johannes Sixt <j6t@xxxxxxxx>
---
compat/mingw.c | 22 ++++++++++++++++++++++
compat/mingw.h | 3 +++
write_or_die.c | 7 +------
3 files changed, 26 insertions(+), 6 deletions(-)
diff --git a/compat/mingw.c b/compat/mingw.c
index afc892d..4e63838 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -335,6 +335,28 @@ FILE *mingw_freopen (const char *filename, const char *otype, FILE *stream)
return freopen(filename, otype, stream);
}
+#undef fflush
+int mingw_fflush(FILE *stream)
+{
+ int ret = fflush(stream);
+
+ /*
+ * write() is used behind the scenes of stdio output functions.
+ * Since git code does not check for errors after each stdio write
+ * operation, it can happen that write() is called by a later
+ * stdio function even if an earlier write() call failed. In the
+ * case of a pipe whose readable end was closed, only the first
+ * call to write() reports EPIPE on Windows. Subsequent write()
+ * calls report EINVAL. It is impossible to notice whether this
+ * fflush invocation triggered such a case, therefore, we have to
+ * catch all EINVAL errors whole-sale.
+ */
+ if (ret && errno == EINVAL)
+ errno = EPIPE;
+
+ return ret;
+}
+
/*
* The unit of FILETIME is 100-nanoseconds since January 1, 1601, UTC.
* Returns the 100-nanoseconds ("hekto nanoseconds") since the epoch.
diff --git a/compat/mingw.h b/compat/mingw.h
index 61a6521..eeb08d1 100644
--- a/compat/mingw.h
+++ b/compat/mingw.h
@@ -185,6 +185,9 @@ FILE *mingw_fopen (const char *filename, const char *otype);
FILE *mingw_freopen (const char *filename, const char *otype, FILE *stream);
#define freopen mingw_freopen
+int mingw_fflush(FILE *stream);
+#define fflush mingw_fflush
+
char *mingw_getcwd(char *pointer, int len);
#define getcwd mingw_getcwd
diff --git a/write_or_die.c b/write_or_die.c
index d45b536..960f448 100644
--- a/write_or_die.c
+++ b/write_or_die.c
@@ -34,12 +34,7 @@ void maybe_flush_or_die(FILE *f, const char *desc)
return;
}
if (fflush(f)) {
- /*
- * On Windows, EPIPE is returned only by the first write()
- * after the reading end has closed its handle; subsequent
- * write()s return EINVAL.
- */
- if (errno == EPIPE || errno == EINVAL)
+ if (errno == EPIPE)
exit(0);
die_errno("write failure on '%s'", desc);
}
--
1.8.0.rc2.1248.g3f5b13f
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