• mem: Replace the Reader interface with a struct for better performance and maintainability. (#8669)

• balancer/pickfirst: Remove support for the old pick_first LB policy via the environment variable GRPC_EXPERIMENTAL_ENABLE_NEW_PICK_FIRST=false. The new pick_first has been the default since v1.71.0. (#8672)

• xdsclient: Fix a race condition in the ADS stream implementation that could result in resource-not-found errors, causing the gRPC client channel to move to TransientFailure. (#8605)
• client: Ignore HTTP status header for gRPC streams. (#8548)
• client: Set a read deadline when closing a transport to prevent it from blocking indefinitely on a broken connection. (#8534)
  • Special Thanks: @jgold2-stripe
• client: Fix a bug where default port 443 was not automatically added to addresses without a specified port when sent to a proxy.
  • Setting environment variable GRPC_EXPERIMENTAL_ENABLE_DEFAULT_PORT_FOR_PROXY_TARGET=false disables this change; please file a bug if any problems are encountered as we will remove this option soon. (#8613)
• balancer/pickfirst: Fix a bug where duplicate addresses were not being ignored as intended. (#8611)
• server: Fix a bug that caused overcounting of channelz metrics for successful and failed streams. (#8573)
  • Special Thanks: @hugehoo
• balancer/pickfirst: When configured, shuffle addresses in resolver updates that lack endpoints. Since gRPC automatically adds endpoints to resolver updates, this bug only affects custom LB policies that delegate to pick_first but don't set endpoints. (#8610)
• mem: Clear large buffers before re-using. (#8670)

• transport: Reduce heap allocations to reduce time spent in garbage collection. (#8624, #8630, #8639, #8668)
• transport: Avoid copies when reading and writing Data frames. (#8657, #8667)
• mem: Avoid clearing newly allocated buffers. (#8670)

• outlierdetection: Add metrics specified in gRFC A91. (#8644)
  • Special Thanks: @davinci26, @PardhuKonakanchi
• stats/opentelemetry: Add support for optional label grpc.lb.backend_service in per-call metrics (#8637)
• xds: Add support for JWT Call Credentials as specified in gRFC A97. Set environment variable GRPC_EXPERIMENTAL_XDS_BOOTSTRAP_CALL_CREDS=true to enable this feature. (#8536)
  • Special Thanks: @dimpavloff
• experimental/stats: Add support for up/down counters. (#8581)

• Minimum supported Go version is now 1.24 (#8509)
  • Special Thanks: @kevinGC

• client: Return status INTERNAL when a server sends zero response messages for a unary or client-streaming RPC. (#8523)
• client: Fail RPCs with status INTERNAL instead of UNKNOWN upon receiving http headers with status 1xx and END_STREAM flag set. (#8518)
  • Special Thanks: @vinothkumarr227
• pick_first: Fix race condition that could cause pick_first to get stuck in IDLE state on backend address change. (#8615)

• credentials: Add credentials/jwt package providing file-based JWT PerRPCCredentials (A97). (#8431)
  • Special Thanks: @dimpavloff

• client: Improve HTTP/2 header size estimate to reduce re-allocations. (#8547)
• encoding/proto: Avoid redundant message size calculation when marshaling. (#8569)
  • Special Thanks: @rs-unity

• server: Fix a regression preventing streams from being cancelled or timed out when blocked on flow control. (https://github.com/grpc/grpc-go/pull/8528)

• server: Fix a regression preventing streams from being cancelled or timed out when blocked on flow control. (https://github.com/grpc/grpc-go/pull/8528)

• xds: Fix a regression preventing empty node IDs in the bootstrap configuration. (#8476 , #8483)
• xdsclient: Fix a data race caused while reporting load to LRS. (#8483)
• server: Fix a regression preventing streams from being cancelled or timed out when blocked on flow control. (#8528)

• transport: Fix a data race while copying headers for stats handlers in the std lib http2 server transport. (#8519)
• xdsclient:
  • Fix a data race caused while reporting load to LRS. (#8483)
  • Fix regression preventing empty node IDs when creating an LRS client. (#8483)
• server: Fix a regression preventing streams from being cancelled or timed out when blocked on flow control. (#8528)

• xds: Remove support for GRPC_EXPERIMENTAL_XDS_FALLBACK environment variable. Fallback support can no longer be disabled. (#8482)
• stats: Introduce DelayedPickComplete event, a type alias of PickerUpdated. (#8465)
  • This (combined) event will now be emitted only once per call, when a transport is successfully selected for the attempt.
  • OpenTelemetry metrics will no longer have multiple "Delayed LB pick complete" events in Go, matching other gRPC languages.
  • A future release will delete the PickerUpdated symbol.
• credentials: Properly apply grpc.WithAuthority as the highest-priority option for setting authority, above the setting in the credentials themselves. (#8488)
  • Now that this WithAuthority is available, the credentials should not be used to override the authority.
• round_robin: Randomize the order in which addresses are connected to in order to spread out initial RPC load between clients. (#8438)
• server: Return status code INTERNAL when a client sends more than one request in unary and server streaming RPC. (#8385)
  • This is a behavior change but also a bug fix to bring gRPC-Go in line with the gRPC spec.

• dns: Add an environment variable (GRPC_ENABLE_TXT_SERVICE_CONFIG) to provide a way to disable TXT lookups in the DNS resolver (by setting it to false). By default, TXT lookups are enabled, as they were previously. (#8377)

• xds: Fix regression preventing empty node IDs in xDS bootstrap configuration. (#8476)
  • Special Thanks: @davinci26
• xds: Fix possible panic when certain invalid resources are encountered. (#8412)
  • Special Thanks: @wooffie
• xdsclient: Fix a rare panic caused by processing a response from a closed server. (#8389)
• stats: Fix metric unit formatting by enclosing non-standard units like call and endpoint in curly braces to comply with UCUM and gRPC OpenTelemetry guidelines. (#8481)
• xds: Fix possible panic when clusters are removed from the xds configuration. (#8428)
• xdsclient: Fix a race causing "resource doesn not exist" when rapidly subscribing and unsubscribing to the same resource. (#8369)
• client: When determining the authority, properly percent-encode (if needed, which is unlikely) when the target string omits the hostname and only specifies a port (grpc.NewClient(":<port-number-or-name>")). (#8488)

• balancer: add ExitIdle method to Balancer interface. Earlier, implementing this method was optional. (#8367)

• xds: Remove the GRPC_EXPERIMENTAL_ENABLE_LEAST_REQUEST environment variable that allows disabling the least request balancer with xDS. Least request was made available by default with xDS in v1.72.0. (#8248)
  • Special Thanks: @atollena
• server: allow 0s grpc-timeout header values, which older gRPC-Java versions could send. This restores the behavior of grpc-go before v1.73.0. (#8439)

• googledirectpath: avoid logging the error message Attempt to set a bootstrap configuration... when creating multiple directpath channels. (#8419)

• transport: reduce heap allocations by pooling objects and avoiding method-to-closure conversions. (#8361)
• transport: reduce heap allocations by re-using mem.Reader objects. (#8360)

• examples: add examples to demonstrate enabling experimental metrics using the OpenTelemetry plugin. (#8388)
  • Special Thanks: @vinothkumarr227

Version 1.74.1 retracts release v1.74.0 and itself. Release 1.74.0 was accidentally tagged on the wrong commit and should not be used. Version 1.73.0 should be used until 1.74.2 is released.

Release 1.74.0 was accidentally tagged on the wrong commit and will be deleted. Please update to 1.74.1 which should be released shortly.