Fix JSON Schema to Grammar for string regexp with top-level alternation. #9903
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Prior to this commit, using a JSON Schema containing a string
with `pattern` regular expression that uses top-level alternation
(e.g. `"pattern": "^A|B|C|D$"`) would result in invalid JSON
output from the constrained sampling grammar, because it
ended up creating a grammar rule like this for the string:
```
thing ::= "\"" "A" | "B" | "C" | "D" "\"" space
```
Note that this rule will only match a starting quote for the "A" case,
and will only match an ending quote for the "D" case,
so this rule will always produce invalid JSON when used for sampling
(that is, the JSON will always be lacking the starting quote,
the ending quote, or both).
This was fixed in a simple way by adding parentheses to the
generated rule (for all string pattern rules, to keep it simple),
such that the new generated rule looks like this (correct):
```
thing ::= "\"" ("A" | "B" | "C" | "D") "\"" space
```
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ggerganov
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Oct 16, 2024
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It's unclear if I can do anything to fix the CI failure with the "Verify server deps" step. I see it also failed on PR #9898, so that makes me suspect the failure is unrelated to this PR. |
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It's already fixed on |
drollings
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Oct 18, 2024
…org#9903) Prior to this commit, using a JSON Schema containing a string with `pattern` regular expression that uses top-level alternation (e.g. `"pattern": "^A|B|C|D$"`) would result in invalid JSON output from the constrained sampling grammar, because it ended up creating a grammar rule like this for the string: ``` thing ::= "\"" "A" | "B" | "C" | "D" "\"" space ``` Note that this rule will only match a starting quote for the "A" case, and will only match an ending quote for the "D" case, so this rule will always produce invalid JSON when used for sampling (that is, the JSON will always be lacking the starting quote, the ending quote, or both). This was fixed in a simple way by adding parentheses to the generated rule (for all string pattern rules, to keep it simple), such that the new generated rule looks like this (correct): ``` thing ::= "\"" ("A" | "B" | "C" | "D") "\"" space ```
dsx1986
pushed a commit
to dsx1986/llama.cpp
that referenced
this pull request
Oct 29, 2024
…org#9903) Prior to this commit, using a JSON Schema containing a string with `pattern` regular expression that uses top-level alternation (e.g. `"pattern": "^A|B|C|D$"`) would result in invalid JSON output from the constrained sampling grammar, because it ended up creating a grammar rule like this for the string: ``` thing ::= "\"" "A" | "B" | "C" | "D" "\"" space ``` Note that this rule will only match a starting quote for the "A" case, and will only match an ending quote for the "D" case, so this rule will always produce invalid JSON when used for sampling (that is, the JSON will always be lacking the starting quote, the ending quote, or both). This was fixed in a simple way by adding parentheses to the generated rule (for all string pattern rules, to keep it simple), such that the new generated rule looks like this (correct): ``` thing ::= "\"" ("A" | "B" | "C" | "D") "\"" space ```
arthw
pushed a commit
to arthw/llama.cpp
that referenced
this pull request
Nov 15, 2024
…org#9903) Prior to this commit, using a JSON Schema containing a string with `pattern` regular expression that uses top-level alternation (e.g. `"pattern": "^A|B|C|D$"`) would result in invalid JSON output from the constrained sampling grammar, because it ended up creating a grammar rule like this for the string: ``` thing ::= "\"" "A" | "B" | "C" | "D" "\"" space ``` Note that this rule will only match a starting quote for the "A" case, and will only match an ending quote for the "D" case, so this rule will always produce invalid JSON when used for sampling (that is, the JSON will always be lacking the starting quote, the ending quote, or both). This was fixed in a simple way by adding parentheses to the generated rule (for all string pattern rules, to keep it simple), such that the new generated rule looks like this (correct): ``` thing ::= "\"" ("A" | "B" | "C" | "D") "\"" space ```
arthw
pushed a commit
to arthw/llama.cpp
that referenced
this pull request
Nov 18, 2024
…org#9903) Prior to this commit, using a JSON Schema containing a string with `pattern` regular expression that uses top-level alternation (e.g. `"pattern": "^A|B|C|D$"`) would result in invalid JSON output from the constrained sampling grammar, because it ended up creating a grammar rule like this for the string: ``` thing ::= "\"" "A" | "B" | "C" | "D" "\"" space ``` Note that this rule will only match a starting quote for the "A" case, and will only match an ending quote for the "D" case, so this rule will always produce invalid JSON when used for sampling (that is, the JSON will always be lacking the starting quote, the ending quote, or both). This was fixed in a simple way by adding parentheses to the generated rule (for all string pattern rules, to keep it simple), such that the new generated rule looks like this (correct): ``` thing ::= "\"" ("A" | "B" | "C" | "D") "\"" space ```
SamuelOliveirads
pushed a commit
to SamuelOliveirads/llama.cpp
that referenced
this pull request
Dec 29, 2025
* grammar : fix JSON Schema for string regex with top-level alt. (ggml-org#9903) Prior to this commit, using a JSON Schema containing a string with `pattern` regular expression that uses top-level alternation (e.g. `"pattern": "^A|B|C|D$"`) would result in invalid JSON output from the constrained sampling grammar, because it ended up creating a grammar rule like this for the string: ``` thing ::= "\"" "A" | "B" | "C" | "D" "\"" space ``` Note that this rule will only match a starting quote for the "A" case, and will only match an ending quote for the "D" case, so this rule will always produce invalid JSON when used for sampling (that is, the JSON will always be lacking the starting quote, the ending quote, or both). This was fixed in a simple way by adding parentheses to the generated rule (for all string pattern rules, to keep it simple), such that the new generated rule looks like this (correct): ``` thing ::= "\"" ("A" | "B" | "C" | "D") "\"" space ``` * grammars : add English-only grammar (ggml-org#10612) * grammar : handle maxItems == 0 in JSON schema (ggml-org#13117) Co-authored-by: Richard Lyons <frob@cloudstaff.com> * grammar-parser : fix possible null-deref (ggml-org#9004) Fixes: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=70680 Signed-off-by: David Korczynski <david@adalogics.com> * llama : fix typo in llama-grammar.h [no ci] (ggml-org#11816) * * server: fix "--grammar-file" parameter (ggml-org#12285) * common : use std::string_view now that we target c++17 (ggml-org#14319) * json : support `enum` values within `allOf` (ggml-org#15830) * grammar : use int64_t to avoid int overflows in int schema to grammar conversion logic (ggml-org#16626) * grammar : support array references in json schema (ggml-org#16792) * grammar : support array references in json schema * Update json-schema-to-grammar.cpp Co-authored-by: Sigbjørn Skjæret <sigbjorn.skjaeret@scala.com> * grammar : improve regex when naming ref derived rules * grammar : replace non-conformant definitions array with anyOf test case --------- Co-authored-by: Sigbjørn Skjæret <sigbjorn.skjaeret@scala.com> # Conflicts: # tests/test-json-schema-to-grammar.cpp * merge fix * llama : minor grammar refactor (ggml-org#10897) * llama: fix error on bad grammar (ggml-org#12628) * grammar : fix integer overflow (ggml-org#17381) * Fix DoS / integer overflow * Remove optional, use INT64_MAX instead as placeholder value (it's technically -1, so it fits :) * White space * Actually, since it's unsigned, use UINT64_MAX # Conflicts: # src/llama-grammar.cpp * grammar: fix regression caused by ggml-org#17381 (ggml-org#17412) * grammar: fix regression caused by ggml-org#17381 * more readable # Conflicts: # src/llama-grammar.cpp * Merge Fix * Fix warnings --------- Signed-off-by: David Korczynski <david@adalogics.com> Co-authored-by: Joe Eli McIlvain <joe.eli.mac@gmail.com> Co-authored-by: Georgi Gerganov <ggerganov@gmail.com> Co-authored-by: frob <rick+github@frob.com.au> Co-authored-by: Richard Lyons <frob@cloudstaff.com> Co-authored-by: DavidKorczynski <david@adalogics.com> Co-authored-by: Daniel Bevenius <daniel.bevenius@gmail.com> Co-authored-by: firecoperana <firecoperana> Co-authored-by: Sigbjørn Skjæret <sigbjorn.skjaeret@scala.com> Co-authored-by: Aldehir Rojas <hello@alde.dev> Co-authored-by: Olivier Chafik <olivier.chafik@gmail.com> Co-authored-by: Piotr Wilkin (ilintar) <piotr.wilkin@syndatis.com> Co-authored-by: Xuan-Son Nguyen <son@huggingface.co> Co-authored-by: Iwan Kawrakow <iwan.kawrakow@gmail.com>
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Prior to this commit, using a JSON Schema containing a string with
patternregular expression that uses top-level alternation (e.g."pattern": "^A|B|C|D$") would result in invalid JSON output from the constrained sampling grammar, because it ended up creating a grammar rule like this for the string:Note that this rule will only match a starting quote for the "A" case, and will only match an ending quote for the "D" case, so this rule will always produce invalid JSON when used for sampling (that is, the JSON will always be lacking the starting quote, the ending quote, or both).
This was fixed in a simple way by adding parentheses to the generated rule (for all string pattern rules, to keep it simple), such that the new generated rule looks like this (correct):