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authorSteffen Prohaska <prohaska@zib.de>2008-02-06 11:25:58 (GMT)
committerJunio C Hamano <gitster@pobox.com>2008-02-06 21:07:28 (GMT)
commit21e5ad50fc5e7277c74cfbb3cf6502468e840f86 (patch)
tree57a0b4cbff7194a705629295d83a4f6ccbd667ef /convert.c
parentef5b9d6e2286630bf8afb5bdf1c6e3356f3d50c7 (diff)
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safecrlf: Add mechanism to warn about irreversible crlf conversions
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 is the right thing to do: it corrects line endings such that we have only LF line endings in the repository. 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. 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 CRLFs are removed in an irreversible way. For text files this is the right thing to do because CRLFs are line endings, while for binary files converting CRLFs corrupts data. 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. Users are only affected by this default if core.autocrlf is set. But the current default of git is to leave core.autocrlf unset, so users will not see warnings unless they deliberately chose to activate the autocrlf mechanism. The safecrlf mechanism's details depend on the git command. The general principles when safecrlf is active (not false) are: - we warn/error out if files in the work tree can modified in an irreversible way without giving the user a chance to backup the original file. - for read-only operations that do not modify files in the work tree we do not not print annoying warnings. There are exceptions. Even though... - "git add" itself does not touch the files in the work tree, the next checkout would, so the safety triggers; - "git apply" to update a text file with a patch does touch the files in the work tree, but the operation is about text files and CRLF conversion is about fixing the line ending inconsistencies, so the safety does not trigger; - "git diff" itself does not touch the files in the work tree, it is often run to inspect the changes you intend to next "git add". To catch potential problems early, safety triggers. 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@zib.de>
Diffstat (limited to 'convert.c')
-rw-r--r--convert.c47
1 files changed, 41 insertions, 6 deletions
diff --git a/convert.c b/convert.c
index 80f114b..3bbf0c5 100644
--- a/convert.c
+++ b/convert.c
@@ -85,8 +85,39 @@ static int is_binary(unsigned long size, struct text_stat *stats)
return 0;
}
+static void check_safe_crlf(const char *path, int action,
+ struct text_stat *stats, enum safe_crlf checksafe)
+{
+ if (!checksafe)
+ return;
+
+ 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 /* i.e. SAFE_CRLF_FAIL */
+ 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("LF will be replaced by CRLF in %s", path);
+ else /* i.e. SAFE_CRLF_FAIL */
+ die("LF would be replaced by CRLF in %s", path);
+ }
+ }
+}
+
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 +126,6 @@ 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 +143,12 @@ static int crlf_to_git(const char *path, const char *src, size_t len,
return 0;
}
+ check_safe_crlf(path, action, &stats, checksafe);
+
+ /* 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 +570,8 @@ 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 +593,7 @@ 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;