The initial motivation for this change was to fix a bug found by fuzzing. The old fuzz test (built on `cc_fuzz_target()`) detected an infinite loop if a bytes field default has an unterminated `\x` escape.
To fix this bug while expanding fuzz coverage, I created a fuzz test that verifies that we can do a lossless round trip from descriptor -> DefPool -> descriptor. We use C++ as the source of truth for whether a descriptor is valid or not, and what the canonical serialization back to protobuf form should be.
I wrote the new fuzz test using go/FuzzTest, which makes it easier and more readable to use an arbitrary `FileDescriptorSet` as input, while adding test cases for regressions.
The fuzz test highlighted a handful of errors that I subsequently fixed and added regression tests for:
1. The aforementioned unterminated `\x` bug.
2. We were not propagating the `edition` field.
3. We were missing the CheckIdent() check in a few places.
4. We were rejecting files with empty name, whereas C++ allows this.
5. There were a few bugs with escaping string defaults.
Since FuzzTest is Clang-only, I split the `FUZZ_TEST()` invocation from the regression tests, since the latter are portable and should be run on all platforms. Only `FUZZ_TEST()` itself is in a google3/Clang-only file.
PiperOrigin-RevId: 506997362
We're already doing a proper string sort in SortedEnums as of cl/503574792, but then we follow it up with a sort on the char* pointers.
PiperOrigin-RevId: 506778694
Our pkg_tar rule was missing a few template files for python. Using setup.py will guarantee conformance with python package requirements.
Adds MANIFEST.in to include c header/inc files in the source distribution.
PiperOrigin-RevId: 506638326
This was already broken, but wasn't caught in tests because `python3` wasn't defined on our windows machines. To prevent it from breaking the entire downstream Bazel workspace when `python3` exists, we mark it unsupported.
PiperOrigin-RevId: 506318286
A while back, the targets were all renamed from "manylinux" to "linux" in order to allow for local testing. However, we still need the release artifacts to use "manylinux" so this conditions the name on whether it is a release or local testing.
PiperOrigin-RevId: 505831116
Slight optimization that frees us from needing to backtrack up to the owning file def to extract the proto syntax bit. Costs zero additional storage since we already have available unused bits. Also makes the enum def the single source of truth for determining enum syntax - upb_FieldDef_IsClosedEnum() now just passes off to upb_EnumDef_IsClosed() instead of replicating that code.
PiperOrigin-RevId: 505513429
To correctly handle this case we must add the serialized map entry to the unknown fields. Ideally we could merely preserve the map entry's serialized bytes from the input. However this is tricky to do if we are streaming and the previous buffer where the map entry began is no longer available.
This CL fixes this edge case by using the encoder to re-encode the map entry rather than using the input bytes directly.
While this fix is reasonably simple and reliable, it has two unfortunate properties. One is performance: we now must run the encoder to recreate bytes that we already saw in the input.
The other is dependencies: this fix has the unfortunate property of making the decoder depend on the encoder. In applications that only want the decoder but not the encoder, this will increase binary size. But the practical effects of this are probably minimal (the vast majority of applications that depend on the decoder will also use the encoder).
We can revisit this later and see if there is a better way of preserving the input bytes without re-encoding. For now this fix is simple and correct and fixes the fuzz bug.
PiperOrigin-RevId: 505381927
It is not useful to include the argument, because this message is only printed when the argument type is `kUpb_CType_Message`.
PiperOrigin-RevId: 505230804
Currently these functions are hardwired to always return true, but the upstream
code now checks for failures (which will be implemented soon).
PiperOrigin-RevId: 504943663
The initial motivation for this CL was to fix a bug found by fuzzing. But the fuzz bug pointed out a few edge cases that this CL corrects:
1. The core bug is that we were allowing a map entry sub-message to be linked to a group field. This is not allowed in protobuf schemas, but we did not check for this edge case in `upb_MiniTable_SetSubMessage()`, so we were de facto allowing it. This triggered some bad behavior in the parser whereby we pushed a limit without checking its validity first.
2. To defend against this, I added asserts in `upb_MiniTable_SetSubMessage()` to verify the type of the field we are linking, to ensure that a group field is not linked to a map entry sub-message. But this should probably be changed to return an error instead of relying on asserts for this.
3. I changed the fuzz util code that builds the MiniTable so that it will never violate this new invariant. The fuzz util code now can run into situations where a group field has no valid non-map-entry sub-message to select. In those cases it will simply not register any sub-message for that field.
4. Previously group did not support leaving sub-messages unregistered. Previously I added this feature for sub-messages but not for groups. There is no reason why dynamic tree shaking should not work for group fields, so I extended the feature to support groups also.
PiperOrigin-RevId: 504913630
According to https://en.cppreference.com/w/c/program/setjmp automatic variables
modified in a function calling setjmp can have indeterminate values. Instead,
refactor all functions calling setjmp so that the function calling setjmp
doesn’t have any local variables.
Part V: Definition protocol buffer converters.
PiperOrigin-RevId: 504817971
According to https://en.cppreference.com/w/c/program/setjmp automatic variables
modified in a function calling setjmp can have indeterminate values. Instead,
refactor all functions calling setjmp so that the function calling setjmp
doesn’t have any local variables.
Part III: Definition pool builders.
PiperOrigin-RevId: 504817954
According to https://en.cppreference.com/w/c/program/setjmp automatic variables
modified in a function calling setjmp can have indeterminate values. Instead,
refactor all functions calling setjmp so that the function calling setjmp
doesn’t have any local variables.
Part VI: Wire encoder/decoder.
PiperOrigin-RevId: 504810940
According to https://en.cppreference.com/w/c/program/setjmp automatic variables
modified in a function calling setjmp can have indeterminate values. Instead,
refactor all functions calling setjmp so that the function calling setjmp
doesn’t have any local variables.
Part IV: Comparison utility.
PiperOrigin-RevId: 504563703
According to https://en.cppreference.com/w/c/program/setjmp automatic variables
modified in a function calling setjmp can have indeterminate values. Instead,
refactor all functions calling setjmp so that the function calling setjmp
doesn’t have any local variables.
Part VI: Code generator.
PiperOrigin-RevId: 504563663
According to https://en.cppreference.com/w/c/program/setjmp automatic variables
modified in a function calling setjmp can have indeterminate values. Instead,
refactor all functions calling setjmp so that the function calling setjmp
doesn’t have any local variables.
Part I: JSON encoder/decoder. The code was previously in compliance, but a
convention of avoiding non-const local variables in functions calling setjmp
will make the compliance more obvious.
PiperOrigin-RevId: 502927863
This is a temporary workaround for the fact that Copybara can only observe a maximum of 30 GitHub Actions success events.
This is necessary to unblock upb CLs.
PiperOrigin-RevId: 502908993
The offsetof trick is not compatible with an incoming Clang change.
Clang has started to enforce that it is UB to declare types inside offsetof. See e327b52766.
```
third_party/upb/upb/mem/arena.c:166:25: error: 'struct (unnamed at third_party/upb/upb/mem/arena.c:166:7)' cannot be defined in '__builtin_offsetof'
n = UPB_ALIGN_DOWN(n, UPB_ALIGN_OF(upb_Arena));
^
./third_party/upb/upb/port/def.inc:113:38: note: expanded from macro 'UPB_ALIGN_OF'
#define UPB_ALIGN_OF(type) offsetof (struct { char c; type member; }, member)
^
third_party/upb/upb/mem/arena.c:166:25: error: 'struct (unnamed at third_party/upb/upb/mem/arena.c:166:7)' cannot be defined in '__builtin_offsetof'
./third_party/upb/upb/port/def.inc:113:38: note: expanded from macro 'UPB_ALIGN_OF'
#define UPB_ALIGN_OF(type) offsetof (struct { char c; type member; }, member)
```
PiperOrigin-RevId: 501872556
This CL changes the upb compiler to no longer depend on C++ protobuf libraries. upb now uses its own reflection libraries to implement its code generator.
# Key Benefits
1. upb can now use its own reflection libraries throughout the compiler. This makes upb more consistent and principled, and gives us more chances to dogfood our own C++ reflection API. This highlighted several parts of the C++ reflection API that were incomplete.
2. This CL removes code duplication that previously existed in the compiler. The upb reflection library has code to build MiniDescriptors and MiniTables out of descriptors, but prior to this CL the upb compiler could not use it. The upb compiler had a separate copy of this logic, and the compiler's copy of this logic was especially tricky and hard to maintain. This CL removes the separate copy of that logic.
3. This CL (mostly) removes upb's dependency on the C++ protobuf library. We still depend on `protoc` (the binary), but the runtime and compiler no longer link against C++'s libraries. This opens up the possibility of speeding up some builds significantly if we can use a prebuilt `protoc` binary.
# Bootstrap Stages
To bootstrap, we check in a copy of our generated code for `descriptor.proto` and `plugin.proto`. This allows the compiler to depend on the generated code for these two protos without creating a circular dependency. This code is checked in to the `stage0` directory.
The bootstrapping process is divided into a few stages. All `cc_library()`, `upb_proto_library()`, and `cc_binary()` targets that would otherwise be circular participate in this staging process. That currently includes:
* `//third_party/upb:descriptor_upb_proto`
* `//third_party/upb:plugin_upb_proto`
* `//third_party/upb:reflection`
* `//third_party/upb:reflection_internal`
* `//third_party/upbc:common`
* `//third_party/upbc:file_layout`
* `//third_party/upbc:plugin`
* `//third_party/upbc:protoc-gen-upb`
For each of these targets, we produce a rule for each stage (the logic for this is nicely encapsulated in Blaze/Bazel macros like `bootstrap_cc_library()` and `bootstrap_upb_proto_library()`, so the `BUILD` file remains readable). For example:
* `//third_party/upb:descriptor_upb_proto_stage0`
* `//third_party/upb:descriptor_upb_proto_stage1`
* `//third_party/upb:descriptor_upb_proto`
The stages are:
1. `stage0`: This uses the checked-in version of the generated code. The stage0 compiler is correct and outputs the same code as all other compilers, but it is unnecessarily slow because its protos were compiled in bootstrap mode. The stage0 compiler is used to generate protos for stage1.
2. `stage1`: The stage1 compiler is correct and fast, and therefore we use it in almost all cases (eg. `upb_proto_library()`). However its own protos were not generated using `upb_proto_library()`, so its `cc_library()` targets cannot be safely mixed with `upb_proto_library()`, as this would lead to duplicate symbols.
3. final (no stage): The final compiler is identical to the `stage1` compiler. The only difference is that its protos were built with `upb_proto_library()`. This doesn't matter very much for the compiler binary, but for the `cc_library()` targets like `//third_party/upb:reflection`, only the final targets can be safely linked in by other applications.
# "Bootstrap Mode" Protos
The checked-in generated code is generated in a special "bootstrap" mode that is a bit different than normal generated code. Bootstrap mode avoids depending on the internal representation of MiniTables or the messages, at the cost of slower runtime performance.
Bootstrap mode only interacts with MiniTables and messages using public APIs such as `upb_MiniTable_Build()`, `upb_Message_GetInt32()`, etc. This is very important as it allows us to change the internal representation without needing to regenerate our bootstrap protos. This will make it far easier to write CLs that change the internal representation, because it avoids the awkward dance of trying to regenerate the bootstrap protos when the compiler itself is broken due to bootstrap protos being out of date.
The bootstrap generated code does have two downsides:
1. The accessors are less efficient, because they look up MiniTable fields by number instead of hard-coding the MiniTableField into the generated code.
2. It requires runtime initialization of the MiniTables, which costs CPU cycles at startup, and also allocates memory which is never freed. Per google3 rules this is not really a leak, since this memory is still reachable via static variables, but it is undesirable in many contexts. We could fix this part by introducing the equivalent of `google::protobuf::ShutdownProtobufLibrary()`).
These downsides are fine for the bootstrapping process, but they are reason enough not to enable bootstrap mode in general for all protos.
# Bootstrapping Always Uses OSS Protos
To enable smooth syncing between Google3 and OSS, we always use an OSS version of the checked in generated code for `stage0`, even in google3.
This requires that the google3 code can be switched to reference the OSS proto names using a preprocessor define. We introduce the `UPB_DESC(xyz)` macro for this, which will expand into either `proto2_xyz` or `google_protobuf_xyz`. Any libraries used in `stage0` must use `UPB_DESC(xyz)` rather than refer to the symbol names directly.
PiperOrigin-RevId: 501458451
Joshua Haberman
Eric Salo
Mike Kruskal
Protobuf Team Bot
Deanna Garcia
Adam Cozzette
Copybara-Service
Dmitri Gribenko
Jie Luo