threads / patch / 49641

v2, 3 partsFix rebase autostash

Subject: [PATCH v2 0/3] Fix rebase autostash

## tl;dr

9 messages between Oct 22, 2018 and Oct 23, 2018. Diffs are folded; open one to read it.

replies: 8people: 5as markdown or json

Johannes Schindelin via GitGitGadget· Oct 22, 2018, 22:15 UTC · lore

Gábor reported in https://public-inbox.org/git/20181019124625.GB30222@szeder.dev/ that t5520-pull.sh fails from time to time, and Alban root-caused this to a bug in the built-in rebase.

This patch series fixes that, and while at it also fixes an oversight of yours truly when helping Pratik with his GSoC project, and it also adds a change on top that makes really, really certain that git stash apply interprets the OID passed to it correctly (as opposed to an insanely large number for the stash reflog).

Please note that I based these patches on top of next (they might be most appropriately applied on top of rebase-in-c-6-final, though).

(Sorry for the v2, v1 did not send due to an UTF-8 character in the Cc: list, a bug that still needs to be fixed in GitGitGadget.)

Johannes Schindelin (3):
  rebase (autostash): avoid duplicate call to state_dir_path()
  rebase (autostash): store the full OID in <state-dir>/autostash
  rebase (autostash): use an explicit OID to apply the stash
 builtin/rebase.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)
base-commit: 500967bb5e73b67708a64a4360867cf2407ba880
Published-As: https://github.com/gitgitgadget/git/releases/tags/pr-52%2Fdscho%2Ffix-rebase-autostash-v2
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-52/dscho/fix-rebase-autostash-v2
Pull-Request: https://github.com/gitgitgadget/git/pull/52
Range-diff vs v1:
 1:  88241ad32 = 1:  88241ad32 rebase (autostash): avoid duplicate call to state_dir_path()
 2:  86107a6d0 = 2:  86107a6d0 rebase (autostash): store the full OID in <state-dir>/autostash
 3:  d3b47a4c1 = 3:  07140a71d rebase (autostash): use an explicit OID to apply the stash
-- 
gitgitgadget
Johannes Schindelin via GitGitGadget· Oct 22, 2018, 22:15 UTC · re: Johannes Schindelin via GitGitGadget · lore

[PATCH v2 3/3] rebase (autostash): use an explicit OID to apply the stash

From: Johannes Schindelin <johannes.schindelin@gmx.de>

When `git stash apply <argument>` sees an argument that consists only of digits, it tries to be smart and interpret it as `stash@{<number>}`.

Unfortunately, an all-digit hash (which is unlikely but still possible) is therefore misinterpreted as `stash@{<n>}` reflog.

To prevent that from happening, let's append `^0` after the stash hash, to make sure that it is interpreted as an OID rather than as a number.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 builtin/rebase.c | 2 ++
 1 file changed, 2 insertions(+)
Show changes to builtin/rebase.c +2 −0
diff --git a/builtin/rebase.c b/builtin/rebase.c
index 418624837..30d58118c 100644
--- a/builtin/rebase.c
+++ b/builtin/rebase.c
@@ -253,6 +253,8 @@ static int apply_autostash(struct rebase_options *opts)
 
 	if (read_one(path, &autostash))
 		return error(_("Could not read '%s'"), path);
+	/* Ensure that the hash is not mistake for a number */
+	strbuf_addstr(&autostash, "^0");
 	argv_array_pushl(&stash_apply.args,
 			 "stash", "apply", autostash.buf, NULL);
 	stash_apply.git_cmd = 1;

-- 
gitgitgadget
Eric Sunshine· Oct 22, 2018, 22:25 UTC · re: Johannes Schindelin via GitGitGadget · lore

Re: [PATCH v2 3/3] rebase (autostash): use an explicit OID to apply the stash

On Mon, Oct 22, 2018 at 6:15 PM Johannes Schindelin via GitGitGadget <gitgitgadget@gmail.com> wrote:

Show 17 quoted lines
> When `git stash apply <argument>` sees an argument that consists only of
> digits, it tries to be smart and interpret it as `stash@{<number>}`.
>
> Unfortunately, an all-digit hash (which is unlikely but still possible)
> is therefore misinterpreted as `stash@{<n>}` reflog.
>
> To prevent that from happening, let's append `^0` after the stash hash,
> to make sure that it is interpreted as an OID rather than as a number.
>
> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
> ---
> diff --git a/builtin/rebase.c b/builtin/rebase.c
> @@ -253,6 +253,8 @@ static int apply_autostash(struct rebase_options *opts)
>
>         if (read_one(path, &autostash))
>                 return error(_("Could not read '%s'"), path);
> +       /* Ensure that the hash is not mistake for a number */
s/mistake/mistaken/
SZEDER Gábor· Oct 22, 2018, 22:32 UTC · re: Johannes Schindelin via GitGitGadget · lore

Re: [PATCH v2 3/3] rebase (autostash): use an explicit OID to apply the stash

On Mon, Oct 22, 2018 at 03:15:05PM -0700, Johannes Schindelin via GitGitGadget wrote:
Show 10 quoted lines
> From: Johannes Schindelin <johannes.schindelin@gmx.de>
> 
> When `git stash apply <argument>` sees an argument that consists only of
> digits, it tries to be smart and interpret it as `stash@{<number>}`.
> 
> Unfortunately, an all-digit hash (which is unlikely but still possible)
> is therefore misinterpreted as `stash@{<n>}` reflog.
> 
> To prevent that from happening, let's append `^0` after the stash hash,
> to make sure that it is interpreted as an OID rather than as a number.
Oh, this is clever.
FWIW, all patches look good to me, barring the typo below.
Show 14 quoted lines
> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
> ---
>  builtin/rebase.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/builtin/rebase.c b/builtin/rebase.c
> index 418624837..30d58118c 100644
> --- a/builtin/rebase.c
> +++ b/builtin/rebase.c
> @@ -253,6 +253,8 @@ static int apply_autostash(struct rebase_options *opts)
>  
>  	if (read_one(path, &autostash))
>  		return error(_("Could not read '%s'"), path);
> +	/* Ensure that the hash is not mistake for a number */
s/mistake/mistaken/
Show 6 quoted lines
> +	strbuf_addstr(&autostash, "^0");
>  	argv_array_pushl(&stash_apply.args,
>  			 "stash", "apply", autostash.buf, NULL);
>  	stash_apply.git_cmd = 1;
> -- 
> gitgitgadget
Junio C Hamano· Oct 23, 2018, 04:13 UTC · re: SZEDER Gábor · lore

Re: [PATCH v2 3/3] rebase (autostash): use an explicit OID to apply the stash

SZEDER Gábor <szeder.dev@gmail.com> writes:
>> To prevent that from happening, let's append `^0` after the stash hash,
>> to make sure that it is interpreted as an OID rather than as a number.
>
> Oh, this is clever.

Yeah, we can do this as we know we'd be dealing with a commit-ish. If we made a mistake to use a tree object to represent a stash, this trick wouldn't have been possible ;-)

Show 5 quoted lines
> FWIW, all patches look good to me, barring the typo below.
> ...
>> +	/* Ensure that the hash is not mistake for a number */
>
> s/mistake/mistaken/
Will squash this in and add your reviewed-by before queuing.
Thanks, both.
Johannes Schindelin· Oct 23, 2018, 09:34 UTC · re: Junio C Hamano · lore

Re: [PATCH v2 3/3] rebase (autostash): use an explicit OID to apply the stash

Hi,
On Tue, 23 Oct 2018, Junio C Hamano wrote:
Show 20 quoted lines
> SZEDER Gábor <szeder.dev@gmail.com> writes:
> 
> >> To prevent that from happening, let's append `^0` after the stash hash,
> >> to make sure that it is interpreted as an OID rather than as a number.
> >
> > Oh, this is clever.
> 
> Yeah, we can do this as we know we'd be dealing with a commit-ish.
> If we made a mistake to use a tree object to represent a stash, this
> trick wouldn't have been possible ;-)
> 
> > FWIW, all patches look good to me, barring the typo below.
> > ...
> >> +	/* Ensure that the hash is not mistake for a number */
> >
> > s/mistake/mistaken/
> 
> Will squash this in and add your reviewed-by before queuing.
> 
> Thanks, both.

Thank you all! Dscho

Johannes Schindelin via GitGitGadget· Oct 22, 2018, 22:15 UTC · re: Johannes Schindelin via GitGitGadget · lore

[PATCH v2 2/3] rebase (autostash): store the full OID in <state-dir>/autostash

From: Johannes Schindelin <johannes.schindelin@gmx.de>

It was reported by Gábor Szeder and analyzed by Alban Gruin that the built-in rebase stores only abbreviated stash hashes in the `autostash` file.

This is problematic e.g. in t5520-pull.sh, where the abbreviated hash is so short that it sometimes consists only of digits, which are subsequently mistaken ("DWIMmed") for numbers by `git stash apply`.

Let's align the behavior of the built-in rebase with the scripted rebase and store the full stash hash instead. That makes it a lot less likely that it consists only of digits.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 builtin/rebase.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
Show changes to builtin/rebase.c +1 −1
diff --git a/builtin/rebase.c b/builtin/rebase.c
index d21504d9f..418624837 100644
--- a/builtin/rebase.c
+++ b/builtin/rebase.c
@@ -1375,7 +1375,7 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 			if (safe_create_leading_directories_const(autostash))
 				die(_("Could not create directory for '%s'"),
 				    options.state_dir);
-			write_file(autostash, "%s", buf.buf);
+			write_file(autostash, "%s", oid_to_hex(&oid));
 			printf(_("Created autostash: %s\n"), buf.buf);
 			if (reset_head(&head->object.oid, "reset --hard",
 				       NULL, 0, NULL, NULL) < 0)

-- 
gitgitgadget
Johannes Schindelin via GitGitGadget· Oct 22, 2018, 22:15 UTC · re: Johannes Schindelin via GitGitGadget · lore

[PATCH v2 1/3] rebase (autostash): avoid duplicate call to state_dir_path()

From: Johannes Schindelin <johannes.schindelin@gmx.de>

We already called that function at this point, and stored the result in the `path` variable. We might just as well use it ;-)

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 builtin/rebase.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
Show changes to builtin/rebase.c +1 −1
diff --git a/builtin/rebase.c b/builtin/rebase.c
index 313a8263d..d21504d9f 100644
--- a/builtin/rebase.c
+++ b/builtin/rebase.c
@@ -251,7 +251,7 @@ static int apply_autostash(struct rebase_options *opts)
 	if (!file_exists(path))
 		return 0;
 
-	if (read_one(state_dir_path("autostash", opts), &autostash))
+	if (read_one(path, &autostash))
 		return error(_("Could not read '%s'"), path);
 	argv_array_pushl(&stash_apply.args,
 			 "stash", "apply", autostash.buf, NULL);

-- 
gitgitgadget

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