# [PATCH] t1402: test forbidden characters in refnames 7 messages from 2026-08-13 to 2026-08-23. Participants: Nikolaus Schuetz via GitGitGadget, Patrick Steinhardt, Junio C Hamano, Nikolaus Schuetz. Thread: https://gitlist.dev/t/66170 ## Nikolaus Schuetz via GitGitGadget, 2026-08-13 20:43 Subject: [PATCH] t1402: test forbidden characters in refnames Message-ID: ``` From: Nikolaus Schuetz git-check-ref-format(1) documents that a refname cannot contain a space, tilde, caret, colon, question-mark, asterisk or open-bracket, and that it cannot be the single character "@". Of these, only "?" was tested as a character embedded in an otherwise-valid refname; "*" was checked only as a lone character or with --refspec-pattern. Add the remaining forbidden characters in that embedded form, and check that "@" alone is rejected even with --allow-onelevel -- where "@" is otherwise a valid refname component, as "refs/@" confirms. Signed-off-by: Nikolaus Schuetz --- t1402: test forbidden characters in refnames git-check-ref-format(1) documents the characters that a refname may not contain (space, tilde, caret, colon, question-mark, asterisk, open-bracket) and the rule that it may not be the single character "@". t1402 only exercised a few of these directly. This adds the remaining forbidden characters in embedded form, and checks that "@" alone is rejected even with --allow-onelevel, where "@" is otherwise a valid refname component (as "refs/@" confirms). Test-only; documents existing behaviour, in the spirit of 919eb8ace (t1402: check for refs ending with a dot). Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-2203%2Fnikolauspschuetz%2Fns%2Ft1402-forbidden-characters-v1 Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-2203/nikolauspschuetz/ns/t1402-forbidden-characters-v1 Pull-Request: https://github.com/gitgitgadget/git/pull/2203 t/t1402-check-ref-format.sh | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/t/t1402-check-ref-format.sh b/t/t1402-check-ref-format.sh index cabc516ae9..bc1e878a0f 100755 --- a/t/t1402-check-ref-format.sh +++ b/t/t1402-check-ref-format.sh @@ -51,12 +51,20 @@ invalid_ref '.refs/foo' invalid_ref 'refs/heads/foo.' invalid_ref 'heads/foo..bar' invalid_ref 'heads/foo?bar' +invalid_ref 'heads/foo~bar' +invalid_ref 'heads/foo^bar' +invalid_ref 'heads/foo:bar' +invalid_ref 'heads/foo*bar' +invalid_ref 'heads/foo[bar' +invalid_ref 'heads/foo bar' valid_ref 'foo./bar' invalid_ref 'heads/foo.lock' invalid_ref 'heads///foo.lock' invalid_ref 'foo.lock/bar' invalid_ref 'foo.lock///bar' valid_ref 'heads/foo@bar' +valid_ref 'refs/@' +invalid_ref '@' --allow-onelevel invalid_ref 'heads/v@{ation' invalid_ref 'heads/foo\bar' invalid_ref "$(printf 'heads/foo\t')" base-commit: 745601a9a94110d74769ab605ccd4f61339758d2 -- gitgitgadget ``` ## Patrick Steinhardt, 2026-08-19 11:20 Subject: Re: [PATCH] t1402: test forbidden characters in refnames Message-ID: In-Reply-To: ``` On Thu, Aug 13, 2026 at 08:43:56PM +0000, Nikolaus Schuetz via GitGitGadget wrote: > From: Nikolaus Schuetz > > git-check-ref-format(1) documents that a refname cannot contain a > space, tilde, caret, colon, question-mark, asterisk or open-bracket, > and that it cannot be the single character "@". Of these, only "?" > was tested as a character embedded in an otherwise-valid refname; > "*" was checked only as a lone character or with --refspec-pattern. > > Add the remaining forbidden characters in that embedded form, and > check that "@" alone is rejected even with --allow-onelevel -- where > "@" is otherwise a valid refname component, as "refs/@" confirms. Okay. > diff --git a/t/t1402-check-ref-format.sh b/t/t1402-check-ref-format.sh > index cabc516ae9..bc1e878a0f 100755 > --- a/t/t1402-check-ref-format.sh > +++ b/t/t1402-check-ref-format.sh > @@ -51,12 +51,20 @@ invalid_ref '.refs/foo' > invalid_ref 'refs/heads/foo.' > invalid_ref 'heads/foo..bar' > invalid_ref 'heads/foo?bar' > +invalid_ref 'heads/foo~bar' > +invalid_ref 'heads/foo^bar' > +invalid_ref 'heads/foo:bar' > +invalid_ref 'heads/foo*bar' > +invalid_ref 'heads/foo[bar' > +invalid_ref 'heads/foo bar' This feels a tiny bit excessive, but I guess it does not hurt to enforce this property, especially now that it's so easy to add new backends. One thing I was briefly wondering is whether we could maybe have a simple loop here, as this feels quite repetitive. We could for example: for c in '?' '~' '^' ':' '*' '[' ' ' do invalid_ref "heads/foo${c}bar" done By the way, one weird bit: is it intentional that all of these really use "heads/something" instead of "refs/heads/something"? I guess it ultimately doesn't matter. > valid_ref 'foo./bar' > invalid_ref 'heads/foo.lock' > invalid_ref 'heads///foo.lock' > invalid_ref 'foo.lock/bar' > invalid_ref 'foo.lock///bar' > valid_ref 'heads/foo@bar' > +valid_ref 'refs/@' > +invalid_ref '@' --allow-onelevel This one certainly is a good addition, as these are quite a bit more subtle. Thanks! Patrick ``` ## Junio C Hamano, 2026-08-19 20:22 Subject: Re: [PATCH] t1402: test forbidden characters in refnames Message-ID: In-Reply-To: ``` Patrick Steinhardt writes: > On Thu, Aug 13, 2026 at 08:43:56PM +0000, Nikolaus Schuetz via GitGitGadget wrote: >> From: Nikolaus Schuetz >> >> git-check-ref-format(1) documents that a refname cannot contain a >> space, tilde, caret, colon, question-mark, asterisk or open-bracket, >> and that it cannot be the single character "@". Of these, only "?" >> was tested as a character embedded in an otherwise-valid refname; >> "*" was checked only as a lone character or with --refspec-pattern. >> >> Add the remaining forbidden characters in that embedded form, and >> check that "@" alone is rejected even with --allow-onelevel -- where >> "@" is otherwise a valid refname component, as "refs/@" confirms. > > Okay. > >> diff --git a/t/t1402-check-ref-format.sh b/t/t1402-check-ref-format.sh >> index cabc516ae9..bc1e878a0f 100755 >> --- a/t/t1402-check-ref-format.sh >> +++ b/t/t1402-check-ref-format.sh >> @@ -51,12 +51,20 @@ invalid_ref '.refs/foo' >> invalid_ref 'refs/heads/foo.' >> invalid_ref 'heads/foo..bar' >> invalid_ref 'heads/foo?bar' >> +invalid_ref 'heads/foo~bar' >> +invalid_ref 'heads/foo^bar' >> +invalid_ref 'heads/foo:bar' >> +invalid_ref 'heads/foo*bar' >> +invalid_ref 'heads/foo[bar' >> +invalid_ref 'heads/foo bar' > > This feels a tiny bit excessive, but I guess it does not hurt to enforce > this property, especially now that it's so easy to add new backends. "Why would we even care to check these insane cases?" was my first reaction, but I agree with you that these are to protect authors of new backends from stupid mistakes. > One thing I was briefly wondering is whether we could maybe have a > simple loop here, as this feels quite repetitive. We could for example: > > for c in '?' '~' '^' ':' '*' '[' ' ' > do > invalid_ref "heads/foo${c}bar" > done True. And c does not have to be a single byte. ".." can also be part of the repertoire. > By the way, one weird bit: is it intentional that all of these really > use "heads/something" instead of "refs/heads/something"? I guess it > ultimately doesn't matter. > >> valid_ref 'foo./bar' >> invalid_ref 'heads/foo.lock' >> invalid_ref 'heads///foo.lock' >> invalid_ref 'foo.lock/bar' >> invalid_ref 'foo.lock///bar' >> valid_ref 'heads/foo@bar' >> +valid_ref 'refs/@' >> +invalid_ref '@' --allow-onelevel > > This one certainly is a good addition, as these are quite a bit more > subtle. > > Thanks! > > Patrick ``` ## Nikolaus Schuetz, 2026-08-20 14:46 Subject: Re: [PATCH] t1402: test forbidden characters in refnames Message-ID: <20260820144648.47267-1-nikolauspschuetz@gmail.com> In-Reply-To: ``` > True. And c does not have to be a single byte. ".." can also be > part of the repertoire. Agreed and updated accordingly: forbidden chars are looped over, and I folded ".." in along with "\" (the same forbidden-char list). The other refname rules enforced by refs.c are well covered, so I kept the loop to the embedded forbidden tokens. > By the way, one weird bit: is it intentional that all of these really > use "heads/something" instead of "refs/heads/something"? Not intentional -- the file already mixes them (e.g. 'refs/heads/foo.' vs 'heads/foo..bar'). check-ref-format validates each component regardless of a refs/ prefix, so it doesn't change what's tested; I kept 'heads/' to match the neighbours. Thanks, Nikolaus ``` ## Nikolaus Schuetz via GitGitGadget, 2026-08-20 22:20 Subject: [PATCH v2] t1402: test forbidden characters in refnames Message-ID: In-Reply-To: ``` From: Nikolaus Schuetz git-check-ref-format(1) documents that a refname cannot contain a space, tilde, caret, colon, question-mark, asterisk, open-bracket or backslash, nor the sequence "..", and cannot be the single character "@". Of these, only "?", "\" and ".." were tested embedded in an otherwise-valid refname; "*" was checked only as a lone character or with --refspec-pattern. Test all of them in that embedded form with a single loop, and check that "@" alone is rejected even with --allow-onelevel -- where "@" is otherwise a valid refname component, as "refs/@" confirms. Signed-off-by: Nikolaus Schuetz --- t1402: test forbidden characters in refnames git-check-ref-format(1) documents the characters that a refname may not contain (space, tilde, caret, colon, question-mark, asterisk, open-bracket) and the rule that it may not be the single character "@". t1402 only exercised a few of these directly. This adds the remaining forbidden characters in embedded form, and checks that "@" alone is rejected even with --allow-onelevel, where "@" is otherwise a valid refname component (as "refs/@" confirms). Test-only; documents existing behaviour, in the spirit of 919eb8ace (t1402: check for refs ending with a dot). Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-2203%2Fnikolauspschuetz%2Fns%2Ft1402-forbidden-characters-v2 Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-2203/nikolauspschuetz/ns/t1402-forbidden-characters-v2 Pull-Request: https://github.com/gitgitgadget/git/pull/2203 Range-diff vs v1: 1: f254db5b09 ! 1: cc013499f9 t1402: test forbidden characters in refnames @@ Commit message t1402: test forbidden characters in refnames git-check-ref-format(1) documents that a refname cannot contain a - space, tilde, caret, colon, question-mark, asterisk or open-bracket, - and that it cannot be the single character "@". Of these, only "?" - was tested as a character embedded in an otherwise-valid refname; - "*" was checked only as a lone character or with --refspec-pattern. + space, tilde, caret, colon, question-mark, asterisk, open-bracket or + backslash, nor the sequence "..", and cannot be the single character + "@". Of these, only "?", "\" and ".." were tested embedded in an + otherwise-valid refname; "*" was checked only as a lone character or + with --refspec-pattern. - Add the remaining forbidden characters in that embedded form, and - check that "@" alone is rejected even with --allow-onelevel -- where - "@" is otherwise a valid refname component, as "refs/@" confirms. + Test all of them in that embedded form with a single loop, and check + that "@" alone is rejected even with --allow-onelevel -- where "@" is + otherwise a valid refname component, as "refs/@" confirms. Signed-off-by: Nikolaus Schuetz ## t/t1402-check-ref-format.sh ## -@@ t/t1402-check-ref-format.sh: invalid_ref '.refs/foo' +@@ t/t1402-check-ref-format.sh: invalid_ref 'foo/./bar' + invalid_ref 'foo/bar/.' + invalid_ref '.refs/foo' invalid_ref 'refs/heads/foo.' - invalid_ref 'heads/foo..bar' - invalid_ref 'heads/foo?bar' -+invalid_ref 'heads/foo~bar' -+invalid_ref 'heads/foo^bar' -+invalid_ref 'heads/foo:bar' -+invalid_ref 'heads/foo*bar' -+invalid_ref 'heads/foo[bar' -+invalid_ref 'heads/foo bar' +-invalid_ref 'heads/foo..bar' +-invalid_ref 'heads/foo?bar' ++for c in '?' '~' '^' ':' '*' '[' ' ' '\' '..' ++do ++ invalid_ref "heads/foo${c}bar" ++done valid_ref 'foo./bar' invalid_ref 'heads/foo.lock' invalid_ref 'heads///foo.lock' @@ t/t1402-check-ref-format.sh: invalid_ref '.refs/foo' +valid_ref 'refs/@' +invalid_ref '@' --allow-onelevel invalid_ref 'heads/v@{ation' - invalid_ref 'heads/foo\bar' +-invalid_ref 'heads/foo\bar' invalid_ref "$(printf 'heads/foo\t')" + invalid_ref "$(printf 'heads/foo\177')" + valid_ref "$(printf 'heads/fu\303\237')" t/t1402-check-ref-format.sh | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/t/t1402-check-ref-format.sh b/t/t1402-check-ref-format.sh index cabc516ae9..9dd64662b2 100755 --- a/t/t1402-check-ref-format.sh +++ b/t/t1402-check-ref-format.sh @@ -49,16 +49,19 @@ invalid_ref 'foo/./bar' invalid_ref 'foo/bar/.' invalid_ref '.refs/foo' invalid_ref 'refs/heads/foo.' -invalid_ref 'heads/foo..bar' -invalid_ref 'heads/foo?bar' +for c in '?' '~' '^' ':' '*' '[' ' ' '\' '..' +do + invalid_ref "heads/foo${c}bar" +done valid_ref 'foo./bar' invalid_ref 'heads/foo.lock' invalid_ref 'heads///foo.lock' invalid_ref 'foo.lock/bar' invalid_ref 'foo.lock///bar' valid_ref 'heads/foo@bar' +valid_ref 'refs/@' +invalid_ref '@' --allow-onelevel invalid_ref 'heads/v@{ation' -invalid_ref 'heads/foo\bar' invalid_ref "$(printf 'heads/foo\t')" invalid_ref "$(printf 'heads/foo\177')" valid_ref "$(printf 'heads/fu\303\237')" base-commit: 745601a9a94110d74769ab605ccd4f61339758d2 -- gitgitgadget ``` ## Junio C Hamano, 2026-08-21 09:29 Subject: Re: [PATCH v2] t1402: test forbidden characters in refnames Message-ID: In-Reply-To: ``` "Nikolaus Schuetz via GitGitGadget" writes: > This adds the remaining forbidden characters in embedded form, and > checks that "@" alone is rejected even with --allow-onelevel, where "@" > is otherwise a valid refname component (as "refs/@" confirms). Many funny characters are not allowed between 'foo' and 'bar', but are there characters other than dot that are not allowed at the beginning or at the end (e.g., "refs/heads/foo." and "foo.lock")? IOW are we testing exhaustive now? > invalid_ref '.refs/foo' > invalid_ref 'refs/heads/foo.' > -invalid_ref 'heads/foo..bar' > -invalid_ref 'heads/foo?bar' > +for c in '?' '~' '^' ':' '*' '[' ' ' '\' '..' > +do > + invalid_ref "heads/foo${c}bar" > +done > valid_ref 'foo./bar' > invalid_ref 'heads/foo.lock' > invalid_ref 'heads///foo.lock' ``` ## Nikolaus Schuetz, 2026-08-23 14:15 Subject: Re: [PATCH v2] t1402: test forbidden characters in refnames Message-ID: <20260823141600.74820-1-nikolauspschuetz@gmail.com> In-Reply-To: ``` > Many funny characters are not allowed between 'foo' and 'bar', but > are there characters other than dot that are not allowed at the > beginning or at the end (e.g., "refs/heads/foo." and "foo.lock")? > > IOW are we testing exhaustive now? No -- dot is the only character with position-specific rules, and every other character in the forbidden set is rejected anywhere in a component. The file already exercises each of those rules on its own -- the leading/trailing-dot, ".lock", empty-component, single-level and --normalize cases are all present. So this isn't reaching for exhaustiveness; the coverage was already broad, and this just fills the untested gap -- of the "forbidden anywhere" characters, only "?", "\" and ".." were tested embedded, so I folded the rest into the loop. Thanks, Nikolaus ```