[PATCH v2 7/7] t7006-pager: if stdout is not a terminal, make a new one
Testing pagination requires (fake or real) access to a terminal so we can see whether the pagination automatically kicks in, which makes it hard to get good coverage when running tests without --verbose. There are a number of ways to work around that:
- Replace all isatty calls with calls to a custom xisatty wrapper
that usually checks for a terminal but can be overridden for tests.
This would be workable, but it would require implementing xisatty
separately in three languages (C, shell, and perl) and making sure
that any code that is to be tested always uses the wrapper.
- Redirect stdout to /dev/tty. This would be problematic because
there might be no terminal available, and even if a terminal is
available, it might not be appropriate to spew output to it.
- Create a new pseudo-terminal on the fly and capture its output.
This patch implements the third approach.
The new test-terminal command opens /dev/ptmx to create a terminal and executes the program specified by its arguments with that terminal as stdout. All platforms I know of with SuSv3 posix_openpt implement it as open("/dev/ptmx", ...), so this should be just as portable.
Pre-SuSv3 systems may not have the proper support, but that is okay. If SVR4 STREAMS are supported, all the functions used by test-terminal will be available and succeed, though the result will not satisfy isatty() unless the appropriate ioctl()s are used. The test suite checks for this and will not use test-terminal in that case.
On non-Unixlike and pre-SVR4 systems, this functionality should be disabled by passing NO_GRANTPT=YesPlease to the makefile. I do not know whether Cygwin or HP-UX implements the required functions appropriately, so to be safe this patch includes that option for them.
On platforms where test-terminal does not work, the test script will maintain its old behavior (skipping most of its tests unless GIT_TEST_OPTS includes --verbose).
Thanks to Brandon Casey <drafnel@gmail.com> and Jeff King <peff@peff.net> for porting help.
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
Brandon Casey wrote:
> On Fri, Feb 19, 2010 at 6:39 PM, Jonathan Nieder <jrnieder@gmail.com> wrote:
Show 6 quoted lines
>> Thanks for trying it out. That’s an excellent outcome: it means that
>> test-terminal compiled without trouble with no makefile magic. It
>> does seem strange to me that there was no error message. Is
>> sh -c "test -t 1" false for an ordinary terminal?
>
> No, it is true. I also substituted /usr/xpg4/bin/sh and got the same result.
Ah, okay. I read up a little more, and it seems that old STREAMS-based implementations of pseudo-terminals require
ioctl(*slave, I_PUSH, "ptem");
ioctl(*slave, I_PUSH, "ldterm");
ioctl(*slave, I_PUSH, "pckt");
where I_PUSH is ('S' << 8) | 2. I am terrified of ioctl number conflicts and do not want to try that, so it is nice to see that this fails so gracefully.
Thanks again. Here’s a revised patch.
.gitignore | 1 +
Makefile | 11 +++++++++
t/t7006-pager.sh | 28 +++++++++++++++--------
test-terminal.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 92 insertions(+), 10 deletions(-)
create mode 100644 test-terminal.c
Show changes to 4 files +92 −10
.gitignore, Makefile, t/t7006-pager.sh, test-terminal.c
diff --git a/.gitignore b/.gitignore
index 8df8f88..6b405ba 100644
--- a/.gitignore
+++ b/.gitignore
@@ -169,6 +169,7 @@
/test-run-command
/test-sha1
/test-sigchain
+/test-terminal
/common-cmds.h
*.tar.gz
*.dsc
diff --git a/Makefile b/Makefile
index 7bf2fca..0df3795 100644
--- a/Makefile
+++ b/Makefile
@@ -55,6 +55,9 @@ all::
#
# Define NO_UNSETENV if you don't have unsetenv in the C library.
#
+# Define NO_GRANTPT if you don't have grantpt, unlockpt, and ptsname
+# (for tests).
+#
# Define NO_MKDTEMP if you don't have mkdtemp in the C library.
#
# Define NO_MKSTEMPS if you don't have mkstemps in the C library.
@@ -803,6 +806,7 @@ ifeq ($(uname_O),Cygwin)
NO_TRUSTABLE_FILEMODE = UnfortunatelyYes
OLD_ICONV = UnfortunatelyYes
NO_ST_BLOCKS_IN_STRUCT_STAT = YesPlease
+ NO_GRANTPT = YesPlease
# There are conflicting reports about this.
# On some boxes NO_MMAP is needed, and not so elsewhere.
# Try commenting this out if you suspect MMAP is more efficient
@@ -910,6 +914,7 @@ ifeq ($(uname_S),HP-UX)
NO_UNSETENV = YesPlease
NO_HSTRERROR = YesPlease
NO_SYS_SELECT_H = YesPlease
+ NO_GRANTPT = YesPlease
SNPRINTF_RETURNS_BOGUS = YesPlease
endif
ifeq ($(uname_S),Windows)
@@ -937,6 +942,7 @@ ifeq ($(uname_S),Windows)
NO_PERL_MAKEMAKER = YesPlease
RUNTIME_PREFIX = YesPlease
NO_POSIX_ONLY_PROGRAMS = YesPlease
+ NO_GRANTPT = YesPlease
NO_ST_BLOCKS_IN_STRUCT_STAT = YesPlease
NO_NSEC = YesPlease
USE_WIN32_MMAP = YesPlease
@@ -989,6 +995,7 @@ ifneq (,$(findstring MINGW,$(uname_S)))
NO_PERL_MAKEMAKER = YesPlease
RUNTIME_PREFIX = YesPlease
NO_POSIX_ONLY_PROGRAMS = YesPlease
+ NO_GRANTPT = YesPlease
NO_ST_BLOCKS_IN_STRUCT_STAT = YesPlease
NO_NSEC = YesPlease
USE_WIN32_MMAP = YesPlease
@@ -1727,6 +1734,10 @@ TEST_PROGRAMS_NEED_X += test-sha1
TEST_PROGRAMS_NEED_X += test-sigchain
TEST_PROGRAMS_NEED_X += test-index-version
+ifndef NO_GRANTPT
+TEST_PROGRAMS_NEED_X += test-terminal
+endif
+
TEST_PROGRAMS = $(patsubst %,%$X,$(TEST_PROGRAMS_NEED_X))
test_bindir_programs := $(patsubst %,bin-wrappers/%,$(BINDIR_PROGRAMS_NEED_X) $(BINDIR_PROGRAMS_NO_X) $(TEST_PROGRAMS_NEED_X))
diff --git a/t/t7006-pager.sh b/t/t7006-pager.sh
index 2e9cb9d..21788e3 100644
--- a/t/t7006-pager.sh
+++ b/t/t7006-pager.sh
@@ -5,18 +5,26 @@ test_description='Test automatic use of a pager.'
. ./test-lib.sh
rm -f stdout_is_tty
-test_expect_success 'is stdout a terminal?' '
+test_expect_success 'set up terminal for tests' '
if test -t 1
then
: > stdout_is_tty
+ elif test-terminal sh -c "test -t 1"
+ then
+ : > test_terminal_works
fi
'
if test -e stdout_is_tty
then
+ test_terminal() { "$@"; }
+ test_set_prereq TTY
+elif test -e test_terminal_works
+then
+ test_terminal() { test-terminal "$@"; }
test_set_prereq TTY
else
- say stdout is not a terminal, so skipping some tests.
+ say no usable terminal, so skipping some tests
fi
unset GIT_PAGER GIT_PAGER_IN_USE
@@ -30,13 +38,13 @@ test_expect_success 'setup' '
rm -f paginated.out
test_expect_success TTY 'some commands use a pager' '
- git log &&
+ test_terminal git log &&
test -e paginated.out
'
rm -f paginated.out
test_expect_success TTY 'some commands do not use a pager' '
- git rev-list HEAD &&
+ test_terminal git rev-list HEAD &&
! test -e paginated.out
'
@@ -54,7 +62,7 @@ test_expect_success 'no pager when stdout is a regular file' '
rm -f paginated.out
test_expect_success TTY 'git --paginate rev-list uses a pager' '
- git --paginate rev-list HEAD &&
+ test_terminal git --paginate rev-list HEAD &&
test -e paginated.out
'
@@ -66,7 +74,7 @@ test_expect_success 'no pager even with --paginate when stdout is a pipe' '
rm -f paginated.out
test_expect_success TTY 'no pager with --no-pager' '
- git --no-pager log &&
+ test_terminal git --no-pager log &&
! test -e paginated.out
'
@@ -127,7 +135,7 @@ test_expect_success SIMPLEPAGER 'default pager is used by default' '
: > default_pager_used
EOF
chmod +x $less &&
- PATH=.:$PATH git log &&
+ PATH=.:$PATH test_terminal git log &&
test -e default_pager_used
'
@@ -137,7 +145,7 @@ rm -f PAGER_used
test_expect_success TTY 'PAGER overrides default pager' '
PAGER=": > PAGER_used" &&
export PAGER &&
- git log &&
+ test_terminal git log &&
test -e PAGER_used
'
@@ -147,7 +155,7 @@ test_expect_success TTY 'core.pager overrides PAGER' '
PAGER=: &&
export PAGER &&
git config core.pager ": > core.pager_used" &&
- git log &&
+ test_terminal git log &&
test -e core.pager_used
'
@@ -156,7 +164,7 @@ test_expect_success TTY 'GIT_PAGER overrides core.pager' '
git config core.pager : &&
GIT_PAGER=": > GIT_PAGER_used" &&
export GIT_PAGER &&
- git log &&
+ test_terminal git log &&
test -e GIT_PAGER_used
'
diff --git a/test-terminal.c b/test-terminal.c
new file mode 100644
index 0000000..6408a7d
--- /dev/null
+++ b/test-terminal.c
@@ -0,0 +1,62 @@
+#include "cache.h"
+#include "run-command.h"
+
+static void newtty(int *master, int *slave)
+{
+ int fd;
+ const char *term;
+
+ fd = open("/dev/ptmx", O_RDWR|O_NOCTTY);
+ if (fd == -1 || grantpt(fd) || unlockpt(fd) || !(term = ptsname(fd)))
+ die_errno("Could not allocate a new pseudo-terminal");
+ *master = fd;
+ *slave = open(term, O_RDWR|O_NOCTTY);
+ if (*slave == -1)
+ die_errno("Could not open pseudo-terminal: %s", term);
+}
+
+static void setup_child(struct child_process *chld,
+ const char **args, int out)
+{
+ memset(chld, 0, sizeof(*chld));
+ chld->argv = args;
+ chld->out = out;
+}
+
+static void xsendfile(int out_fd, int in_fd)
+{
+ char buf[BUFSIZ];
+
+ /* Note: the real sendfile() cannot read from a terminal. */
+ for (;;) {
+ ssize_t n = xread(in_fd, buf, sizeof(buf));
+
+ /*
+ * It is unspecified by POSIX whether reads
+ * from a disconnected terminal will return
+ * EIO (as in AIX 4.x, IRIX, and Linux) or
+ * end-of-file. Either is fine.
+ */
+ if (n == 0 || (n == -1 && errno == EIO))
+ break;
+ if (n == -1)
+ die_errno("cannot read from child");
+ write_or_die(out_fd, buf, n);
+ }
+}
+
+int main(int argc, const char **argv)
+{
+ int masterfd, slavefd;
+ struct child_process chld;
+
+ if (argc < 2 || (argc == 2 && !strcmp(argv[1], "-h")))
+ usage("test-terminal program args");
+
+ newtty(&masterfd, &slavefd);
+ setup_child(&chld, argv + 1, slavefd);
+ if (start_command(&chld))
+ return error("failed to execute child");
+ xsendfile(1, masterfd);
+ return finish_command(&chld);
+}
--
1.7.0
Jonathan Nieder
