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Revision b018ff60857ee7d79e3c4a8772bac08656a2a3c6 authored by Jeff King on 29 December 2012, 20:51:54 UTC, committed by Junio C Hamano on 04 November 2013, 18:13:27 UTC 
unpack-trees: fix "read-tree -u --reset A B" with conflicted index
 
When we call "read-tree --reset -u HEAD ORIG_HEAD", the first thing we
do with the index is to call read_cache_unmerged.  Originally that
would read the index, leaving aside any unmerged entries.  However, as
of d1a43f2 (reset --hard/read-tree --reset -u: remove unmerged new
paths, 2008-10-15), it actually creates a new cache entry to serve as
a placeholder, so that we later know to update the working tree.

However, we later noticed that the sha1 of that unmerged entry was
just copied from some higher stage, leaving you with random content in
the index.  That was fixed by e11d7b5 ("reset --merge": fix unmerged
case, 2009-12-31), which instead puts the null sha1 into the newly
created entry, and sets a CE_CONFLICTED flag. At the same time, it
teaches the unpack-trees machinery to pay attention to this flag, so
that oneway_merge throws away the current value.

However, it did not update the code paths for twoway_merge, which is
where we end up in the two-way read-tree with --reset. We notice that
the HEAD and ORIG_HEAD versions are the same, and say "oh, we can just
reuse the current version". But that's not true. The current version
is bogus.

Notice this case and make sure we do not keep the bogus entry; either
we do not have that path in the tree we are moving to (i.e. remove
it), or we want to have the cache entry we created for the tree we are
moving to (i.e. resolve by explicitly saying the "newtree" version is
what we want).

[jc: this is from the almost year-old $gmane/212316]

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
1 parent c479d14
Raw File
pager.c 
#include "cache.h"
#include "run-command.h"
#include "sigchain.h"

#ifndef DEFAULT_PAGER
#define DEFAULT_PAGER "less"
#endif

/*
 * This is split up from the rest of git so that we can do
 * something different on Windows.
 */

#ifndef WIN32
static void pager_preexec(void)
{
	/*
	 * Work around bug in "less" by not starting it until we
	 * have real input
	 */
	fd_set in;

	FD_ZERO(&in);
	FD_SET(0, &in);
	select(1, &in, NULL, &in, NULL);
}
#endif

static const char *pager_argv[] = { NULL, NULL };
static struct child_process pager_process;

static void wait_for_pager(void)
{
	fflush(stdout);
	fflush(stderr);
	/* signal EOF to pager */
	close(1);
	close(2);
	finish_command(&pager_process);
}

static void wait_for_pager_signal(int signo)
{
	wait_for_pager();
	sigchain_pop(signo);
	raise(signo);
}

const char *git_pager(int stdout_is_tty)
{
	const char *pager;

	if (!stdout_is_tty)
		return NULL;

	pager = getenv("GIT_PAGER");
	if (!pager) {
		if (!pager_program)
			git_config(git_default_config, NULL);
		pager = pager_program;
	}
	if (!pager)
		pager = getenv("PAGER");
	if (!pager)
		pager = DEFAULT_PAGER;
	else if (!*pager || !strcmp(pager, "cat"))
		pager = NULL;

	return pager;
}

void setup_pager(void)
{
	const char *pager = git_pager(isatty(1));

	if (!pager)
		return;

	/*
	 * force computing the width of the terminal before we redirect
	 * the standard output to the pager.
	 */
	(void) term_columns();

	setenv("GIT_PAGER_IN_USE", "true", 1);

	/* spawn the pager */
	pager_argv[0] = pager;
	pager_process.use_shell = 1;
	pager_process.argv = pager_argv;
	pager_process.in = -1;
	if (!getenv("LESS")) {
		static const char *env[] = { "LESS=FRSX", NULL };
		pager_process.env = env;
	}
#ifndef WIN32
	pager_process.preexec_cb = pager_preexec;
#endif
	if (start_command(&pager_process))
		return;

	/* original process continues, but writes to the pipe */
	dup2(pager_process.in, 1);
	if (isatty(2))
		dup2(pager_process.in, 2);
	close(pager_process.in);

	/* this makes sure that the parent terminates after the pager */
	sigchain_push_common(wait_for_pager_signal);
	atexit(wait_for_pager);
}

int pager_in_use(void)
{
	const char *env;
	env = getenv("GIT_PAGER_IN_USE");
	return env ? git_config_bool("GIT_PAGER_IN_USE", env) : 0;
}

/*
 * Return cached value (if set) or $COLUMNS environment variable (if
 * set and positive) or ioctl(1, TIOCGWINSZ).ws_col (if positive),
 * and default to 80 if all else fails.
 */
int term_columns(void)
{
	static int term_columns_at_startup;

	char *col_string;
	int n_cols;

	if (term_columns_at_startup)
		return term_columns_at_startup;

	term_columns_at_startup = 80;

	col_string = getenv("COLUMNS");
	if (col_string && (n_cols = atoi(col_string)) > 0)
		term_columns_at_startup = n_cols;
#ifdef TIOCGWINSZ
	else {
		struct winsize ws;
		if (!ioctl(1, TIOCGWINSZ, &ws) && ws.ws_col)
			term_columns_at_startup = ws.ws_col;
	}
#endif

	return term_columns_at_startup;
}
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