This repaces v6 of the patch and includes the following changes
- Reason behind safecrlf documented in config.txt
- git apply exactly behaves as configured in core.safecrlf
Steffen
---- snip ---
CRLF conversion bears a slight chance of corrupting data.
autocrlf=true will convert CRLF to LF during commit and LF to
CRLF during checkout. A file that contains a mixture of LF and
CRLF before the commit cannot be recreated by git. For text
files this does not really matter because we do not care about
the line endings anyway; but for binary files that are
accidentally classified as text the conversion can corrupt data.
If you recognize such corruption early you can easily fix it by
setting the conversion type explicitly in .gitattributes. Right
after committing you still have the original file in your work
tree and this file is not yet corrupted. You can explicitly tell
git that this file is binary and git will handle the file
appropriately.
In mixed Windows/Unix environments text files quite easily can
end up containing a mixture of CRLF and LF line endings and git
should handle such situations gracefully. For example, a user
could copy a CRLF file from Windows to Unix and mix it with an
existing LF file there. The result would contain both types of
line endings.
Unfortunately, the desired effect of cleaning up text files with
mixed line endings and the undesired effect of corrupting binary
files cannot be distinguished. In both cases CRLF endings are
removed in an irreversible way. For text files this is the right
thing to do, while for binary file it corrupts data.
In a sane environment, committing and checking out the same file
should not modify the original file in the work tree. For
autocrlf=input the original file must not contain CRLF. For
autocrlf=true the original file must not contain LF without
preceding CR. Otherwise the conversion is irreversible. Note,
git might be able to recreate the original file with different
autocrlf settings, but in the current environment checking out
will yield a file that differs from the file before the commit.
This patch adds a mechanism that can either warn the user about
an irreversible conversion or can even refuse to convert. The
mechanism is controlled by the variable core.safecrlf, with the
following values
- false: disable safecrlf mechanism
- warn: warn about irreversible conversions
- true: refuse irreversible conversions
The default is to warn.
The safecrlf mechanism's details depend on the git command. If
safecrlf is active (not false), files in the work tree must not
be modified in an irreversible way without giving the user a
chance to backup the original file. However, for read-only
operations that do not modify files in the work tree git should
not print annoying warnings.
git apply behave as requested by by safecrlf. Even though
git apply writes changes directly back to the work tree, the
user still can get the original files back by checking out from
the index or HEAD. git apply should only be run on a clean
work tree.
git diff, git add, and any other command that calls
index_fd(..., write_object=1) also behave as requested by
safecrlf. The user still has the chance to save her data before
checkout or applying the diff.
git blame will never warn nor fail because it never writes to the
work tree.
The concept of a safety check was originally proposed in a similar
way by Linus Torvalds. Thanks to Dimitry Potapov for insisting
on getting the naked LF/autocrlf=true case right.
Signed-off-by: Steffen Prohaska <prohaska@xxxxxx>
---
Documentation/config.txt | 50 +++++++++++++++++++++++++++++++++
Documentation/gitattributes.txt | 5 +++
builtin-apply.c | 2 +-
builtin-blame.c | 2 +-
cache.h | 10 ++++++-
config.c | 9 ++++++
convert.c | 34 +++++++++++++++++++----
diff.c | 2 +-
environment.c | 1 +
sha1_file.c | 2 +-
t/t0020-crlf.sh | 58 +++++++++++++++++++++++++++++++++++++++
11 files changed, 164 insertions(+), 11 deletions(-)
diff --git a/Documentation/config.txt b/Documentation/config.txt
index 4e222f1..7ebee51 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -139,6 +139,56 @@ core.autocrlf::
"text" (i.e. be subjected to the autocrlf mechanism) is
decided purely based on the contents.
+core.safecrlf::
+ If true, makes git check if converting `CRLF` as controlled by
+ `core.autocrlf` is reversible. Git will verify if a command
+ modifies a file in the work tree either directly or indirectly.
+ For example, committing a file followed by checking out the
+ same file should yield the original file in the work tree. If
+ this is not the case for the current setting of
+ `core.autocrlf`, git will reject the file. The variable can
+ be set to "warn", in which case git will only warn about an
+ irreversible conversion but continue the operation.
++
+CRLF conversion bears a slight chance of corrupting data.
+autocrlf=true will convert CRLF to LF during commit and LF to
+CRLF during checkout. A file that contains a mixture of LF and
+CRLF before the commit cannot be recreated by git. For text
+files this does not really matter because we do not care about
+the line endings anyway; but for binary files that are
+accidentally classified as text the conversion can corrupt data.
++
+If you recognize such corruption early you can easily fix it by
+setting the conversion type explicitly in .gitattributes. Right
+after committing you still have the original file in your work
+tree and this file is not yet corrupted. You can explicitly tell
+git that this file is binary and git will handle the file
+appropriately.
++
+In mixed Windows/Unix environments text files quite easily can
+end up containing a mixture of CRLF and LF line endings and git
+should handle such situations gracefully. For example, a user
+could copy a CRLF file from Windows to Unix and mix it with an
+existing LF file there. The result would contain both types of
+line endings.
++
+Unfortunately, the desired effect of cleaning up text files with
+mixed line endings and the undesired effect of corrupting binary
+files cannot be distinguished. In both cases CRLF endings are
+removed in an irreversible way. For text files this is the right
+thing to do, while for binary file it corrupts data.
++
+Note, this safety check does not mean that a checkout will generate a
+file identical to the original file for a different setting of
+`core.autocrlf`, but only for the current one. For example, a text
+file with `LF` would be accepted with `core.autocrlf=input` and could
+later be checked out with `core.autocrlf=true`, in which case the
+resulting file would contain `CRLF`, although the original file
+contained `LF`. However, in both work trees the line endings would be
+consistent, that is either all `LF` or all `CRLF`, but never mixed. A
+file with mixed line endings would be reported by the `core.safecrlf`
+mechanism.
+
core.symlinks::
If false, symbolic links are checked out as small plain files that
contain the link text. linkgit:git-update-index[1] and
diff --git a/Documentation/gitattributes.txt b/Documentation/gitattributes.txt
index 35a29fd..2ffe1fb 100644
--- a/Documentation/gitattributes.txt
+++ b/Documentation/gitattributes.txt
@@ -133,6 +133,11 @@ When `core.autocrlf` is set to "input", line endings are
converted to LF upon checkin, but there is no conversion done
upon checkout.
+If `core.safecrlf` is set to "true" or "warn", git verifies if
+the conversion is reversible for the current setting of
+`core.autocrlf`. For "true", git rejects irreversible
+conversions; for "warn", git only prints a warning but accepts
+an irreversible conversion.
`ident`
^^^^^^^
diff --git a/builtin-apply.c b/builtin-apply.c
index 15432b6..d0b3586 100644
--- a/builtin-apply.c
+++ b/builtin-apply.c
@@ -1430,7 +1430,7 @@ static int read_old_data(struct stat *st, const char *path, struct strbuf *buf)
case S_IFREG:
if (strbuf_read_file(buf, path, st->st_size) != st->st_size)
return error("unable to open or read %s", path);
- convert_to_git(path, buf->buf, buf->len, buf);
+ convert_to_git(path, buf->buf, buf->len, buf, safe_crlf);
return 0;
default:
return -1;
diff --git a/builtin-blame.c b/builtin-blame.c
index 9b4c02e..c361ee1 100644
--- a/builtin-blame.c
+++ b/builtin-blame.c
@@ -2073,7 +2073,7 @@ static struct commit *fake_working_tree_commit(const char *path, const char *con
if (strbuf_read(&buf, 0, 0) < 0)
die("read error %s from stdin", strerror(errno));
}
- convert_to_git(path, buf.buf, buf.len, &buf);
+ convert_to_git(path, buf.buf, buf.len, &buf, 0);
origin->file.ptr = buf.buf;
origin->file.size = buf.len;
pretend_sha1_file(buf.buf, buf.len, OBJ_BLOB, origin->blob_sha1);
diff --git a/cache.h b/cache.h
index 549f4bb..f8223a6 100644
--- a/cache.h
+++ b/cache.h
@@ -330,6 +330,14 @@ extern size_t packed_git_limit;
extern size_t delta_base_cache_limit;
extern int auto_crlf;
+enum safe_crlf {
+ SAFE_CRLF_FALSE = 0,
+ SAFE_CRLF_FAIL = 1,
+ SAFE_CRLF_WARN = 2,
+};
+
+extern enum safe_crlf safe_crlf;
+
#define GIT_REPO_VERSION 0
extern int repository_format_version;
extern int check_repository_format(void);
@@ -633,7 +641,7 @@ extern void trace_argv_printf(const char **argv, const char *format, ...);
/* convert.c */
/* returns 1 if *dst was used */
-extern int convert_to_git(const char *path, const char *src, size_t len, struct strbuf *dst);
+extern int convert_to_git(const char *path, const char *src, size_t len, struct strbuf *dst, enum safe_crlf checksafe);
extern int convert_to_working_tree(const char *path, const char *src, size_t len, struct strbuf *dst);
/* add */
diff --git a/config.c b/config.c
index 526a3f4..5fe7cce 100644
--- a/config.c
+++ b/config.c
@@ -407,6 +407,15 @@ int git_default_config(const char *var, const char *value)
return 0;
}
+ if (!strcmp(var, "core.safecrlf")) {
+ if (value && !strcasecmp(value, "warn")) {
+ safe_crlf = SAFE_CRLF_WARN;
+ return 0;
+ }
+ safe_crlf = git_config_bool(var, value);
+ return 0;
+ }
+
if (!strcmp(var, "user.name")) {
strlcpy(git_default_name, value, sizeof(git_default_name));
return 0;
diff --git a/convert.c b/convert.c
index 80f114b..d580a62 100644
--- a/convert.c
+++ b/convert.c
@@ -86,7 +86,7 @@ static int is_binary(unsigned long size, struct text_stat *stats)
}
static int crlf_to_git(const char *path, const char *src, size_t len,
- struct strbuf *buf, int action)
+ struct strbuf *buf, int action, enum safe_crlf checksafe)
{
struct text_stat stats;
char *dst;
@@ -95,9 +95,6 @@ static int crlf_to_git(const char *path, const char *src, size_t len,
return 0;
gather_stats(src, len, &stats);
- /* No CR? Nothing to convert, regardless. */
- if (!stats.cr)
- return 0;
if (action == CRLF_GUESS) {
/*
@@ -115,6 +112,30 @@ static int crlf_to_git(const char *path, const char *src, size_t len,
return 0;
}
+ if (checksafe) {
+ if (action == CRLF_INPUT || auto_crlf <= 0) {
+ /* CRLFs would not be restored by checkout: check if we'd remove CRLFs */
+ if (stats.crlf) {
+ if (checksafe == SAFE_CRLF_WARN)
+ warning("CRLF will be replaced by LF in %s.", path);
+ else
+ die("CRLF would be replaced by LF in %s.", path);
+ }
+ } else if (auto_crlf > 0) {
+ /* CRLFs would be added by checkout: check if we have "naked" LFs */
+ if (stats.lf != stats.crlf) {
+ if (checksafe == SAFE_CRLF_WARN)
+ warning("LFs will be replaced by CRLF in %s", path);
+ else
+ die("LF would be replaced by CRLF in %s", path);
+ }
+ }
+ }
+
+ /* Optimization: No CR? Nothing to convert, regardless. */
+ if (!stats.cr)
+ return 0;
+
/* only grow if not in place */
if (strbuf_avail(buf) + buf->len < len)
strbuf_grow(buf, len - buf->len);
@@ -536,7 +557,8 @@ static int git_path_check_ident(const char *path, struct git_attr_check *check)
return !!ATTR_TRUE(value);
}
-int convert_to_git(const char *path, const char *src, size_t len, struct strbuf *dst)
+int convert_to_git(const char *path, const char *src, size_t len,
+ struct strbuf *dst, enum safe_crlf checksafe)
{
struct git_attr_check check[3];
int crlf = CRLF_GUESS;
@@ -558,7 +580,7 @@ int convert_to_git(const char *path, const char *src, size_t len, struct strbuf
src = dst->buf;
len = dst->len;
}
- ret |= crlf_to_git(path, src, len, dst, crlf);
+ ret |= crlf_to_git(path, src, len, dst, crlf, checksafe);
if (ret) {
src = dst->buf;
len = dst->len;
diff --git a/diff.c b/diff.c
index 5b8afdc..562c20e 100644
--- a/diff.c
+++ b/diff.c
@@ -1624,7 +1624,7 @@ int diff_populate_filespec(struct diff_filespec *s, int size_only)
* Convert from working tree format to canonical git format
*/
strbuf_init(&buf, 0);
- if (convert_to_git(s->path, s->data, s->size, &buf)) {
+ if (convert_to_git(s->path, s->data, s->size, &buf, safe_crlf)) {
size_t size = 0;
munmap(s->data, s->size);
s->should_munmap = 0;
diff --git a/environment.c b/environment.c
index 18a1c4e..e351e99 100644
--- a/environment.c
+++ b/environment.c
@@ -35,6 +35,7 @@ int pager_use_color = 1;
char *editor_program;
char *excludes_file;
int auto_crlf = 0; /* 1: both ways, -1: only when adding git objects */
+enum safe_crlf safe_crlf = SAFE_CRLF_WARN;
unsigned whitespace_rule_cfg = WS_DEFAULT_RULE;
/* This is set by setup_git_dir_gently() and/or git_default_config() */
diff --git a/sha1_file.c b/sha1_file.c
index 66a4e00..1cf8337 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -2358,7 +2358,7 @@ int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object,
if ((type == OBJ_BLOB) && S_ISREG(st->st_mode)) {
struct strbuf nbuf;
strbuf_init(&nbuf, 0);
- if (convert_to_git(path, buf, size, &nbuf)) {
+ if (convert_to_git(path, buf, size, &nbuf, write_object ? safe_crlf : 0)) {
munmap(buf, size);
buf = strbuf_detach(&nbuf, &size);
re_allocated = 1;
diff --git a/t/t0020-crlf.sh b/t/t0020-crlf.sh
index 8b27aa8..90ea081 100755
--- a/t/t0020-crlf.sh
+++ b/t/t0020-crlf.sh
@@ -8,6 +8,10 @@ q_to_nul () {
tr Q '\000'
}
+q_to_cr () {
+ tr Q '\015'
+}
+
append_cr () {
sed -e 's/$/Q/' | tr Q '\015'
}
@@ -42,6 +46,60 @@ test_expect_success setup '
echo happy.
'
+test_expect_success 'safecrlf: autocrlf=input, all CRLF' '
+
+ git config core.autocrlf input &&
+ git config core.safecrlf true &&
+
+ for w in I am all CRLF; do echo $w; done | append_cr >allcrlf &&
+ ! git add allcrlf
+'
+
+test_expect_success 'safecrlf: autocrlf=input, mixed LF/CRLF' '
+
+ git config core.autocrlf input &&
+ git config core.safecrlf true &&
+
+ for w in Oh here is CRLFQ in text; do echo $w; done | q_to_cr >mixed &&
+ ! git add mixed
+'
+
+test_expect_success 'safecrlf: autocrlf=true, all LF' '
+
+ git config core.autocrlf true &&
+ git config core.safecrlf true &&
+
+ for w in I am all LF; do echo $w; done >alllf &&
+ ! git add alllf
+'
+
+test_expect_success 'safecrlf: autocrlf=true mixed LF/CRLF' '
+
+ git config core.autocrlf true &&
+ git config core.safecrlf true &&
+
+ for w in Oh here is CRLFQ in text; do echo $w; done | q_to_cr >mixed &&
+ ! git add mixed
+'
+
+test_expect_success 'safecrlf: print warning only once' '
+
+ git config core.autocrlf input &&
+ git config core.safecrlf warn &&
+
+ for w in I am all LF; do echo $w; done >doublewarn &&
+ git add doublewarn &&
+ git commit -m "nowarn" &&
+ for w in Oh here is CRLFQ in text; do echo $w; done | q_to_cr >doublewarn &&
+ test $(git add doublewarn 2>&1 | grep "CRLF will be replaced by LF" | wc -l) = 1
+'
+
+test_expect_success 'switch off autocrlf, safecrlf, reset HEAD' '
+ git config core.autocrlf false &&
+ git config core.safecrlf false &&
+ git reset --hard HEAD^
+'
+
test_expect_success 'update with autocrlf=input' '
rm -f tmp one dir/two three &&
--
1.5.4.19.g5f7bf
-
To unsubscribe from this list: send the line "unsubscribe git" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
