refactor: replace httpgd-js with built-in transports

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changelog
 
+## Unreleased
+
+- The httpgd plot backend now requires the `httpgd` R package version 2.0.1 or later. Older versions are treated as unavailable when choosing the plot backend. (#1855)
+
 ## 3.0.1 - 2026-09-28
 
 - Bump version of both the extension and `sess` to `3.0.1` so users who installed an earlier `3.0.0` pre-release build of `sess` (before its connection protocol was finalized) are prompted to reinstall `sess`. (#1794)

package.json

@@ -27,7 +27,7 @@
     "R Markdown"
   ],
   "engines": {
-    "vscode": "^1.94.0"
+    "vscode": "^1.98.2"
   },
   "activationEvents": [
     "workspaceContains:**/*.{rproj,Rproj,r,R,rd,Rd,rmd,Rmd}",
@@ -2216,7 +2216,7 @@
           "default": false,
           "scope": "window",
           "ignoreSync": true,
-          "markdownDescription": "Legacy compatibility setting for selecting the httpgd plot viewer. When `#r.plot.backend#` is `auto`, setting this to `true` selects the `httpgd` backend. Workspace settings take precedence over user settings. Within the same scope, an explicit `#r.plot.backend#` value takes precedence.\n\nRequires the `httpgd` R package version 1.2.0 or later.",
+          "markdownDescription": "Legacy compatibility setting for selecting the httpgd plot viewer. When `#r.plot.backend#` is `auto`, setting this to `true` selects the `httpgd` backend. Workspace settings take precedence over user settings. Within the same scope, an explicit `#r.plot.backend#` value takes precedence.\n\nRequires the `httpgd` R package version 2.0.1 or later.",
           "markdownDeprecationMessage": "Deprecated: use `#r.plot.backend#` instead. This setting is retained for compatibility with existing configurations but will be removed in a future release.",
           "deprecationMessage": "Deprecated: use r.plot.backend instead. This setting is retained for compatibility with existing configurations but will be removed in a future release."
         },
@@ -2567,7 +2567,6 @@
     "cheerio": "1.0.0-rc.12",
     "ejs": "^3.1.10",
     "highlight.js": "^11.11.1",
-    "httpgd": "0.1.6",
     "js-yaml": "^4.3.2",
     "vscode-languageclient": "^10.1.2",
     "winreg": "^1.2.5"

sess/R/hooks.R

@@ -215,8 +215,10 @@ runtime_start <- function(use_rstudioapi = TRUE,
   .sess_env$runtime_start_phase <- "plot"
   has_jgd <- plot_backend %in% c("auto", "jgd") &&
     nzchar(Sys.getenv("JGD_SOCKET")) && requireNamespace("jgd", quietly = TRUE)
+  # The built-in client requires the 2.x renderer schema, including descr.
   has_httpgd <- plot_backend %in% c("auto", "httpgd") &&
-    requireNamespace("httpgd", quietly = TRUE)
+    requireNamespace("httpgd", quietly = TRUE) &&
+    package_version(getNamespaceVersion("httpgd")) >= "2.0.1"
   selected_backend <- .select_plot_backend(plot_backend, has_httpgd, has_jgd)
   if (selected_backend == "jgd") {
     .runtime_set_option("device", function(...) {
@@ -270,9 +272,9 @@ runtime_start <- function(use_rstudioapi = TRUE,
                 "connection is available. Falling back to the standard plot ",
                 "viewer.", call. = FALSE)
       } else if (plot_backend == "httpgd") {
-        warning("[sess] Plot backend \"httpgd\" was requested but the httpgd ",
-                "package is not installed. Falling back to the standard plot ",
-                "viewer. Install httpgd, or change the r.plot.backend setting.",
+        warning("[sess] Plot backend \"httpgd\" requires httpgd >= 2.0.1. ",
+                "Falling back to the standard plot viewer. ",
+                "Install or update httpgd, or change the r.plot.backend setting.",
                 call. = FALSE)
       }
     }

sess/inst/tinytest/test-httpgd-version.R

@@ -0,0 +1,38 @@
+# Exercise the real backend selection without installing old httpgd binaries.
+local({
+  sess_env <- sess:::.sess_env
+  old_plot_path <- sess_env$latest_plot_path
+  sess_env$latest_plot_path <- tempfile(fileext = ".png")
+  on.exit({
+    sess:::runtime_stop()
+    unlink(sess_env$latest_plot_path)
+    sess_env$latest_plot_path <- old_plot_path
+  })
+
+  env <- new.env(parent = asNamespace("sess"))
+  start <- sess:::runtime_start
+  environment(start) <- env
+  env$requireNamespace <- function(package, ...) {
+    identical(package, "httpgd") && !is.null(version)
+  }
+  env$getNamespaceVersion <- function(package) version
+  versions <- list(NULL, "1.2.0", "2.0.0", "2.0.1", "2.1.4", "10.0.0")
+  supported <- c(FALSE, FALSE, FALSE, TRUE, TRUE, TRUE)
+  for (i in seq_along(versions)) {
+    version <- versions[[i]]
+    for (backend in c("auto", "httpgd")) {
+      warnings <- character()
+      withCallingHandlers(
+        start(use_rstudioapi = FALSE, plot_backend = backend),
+        warning = function(w) {
+          warnings <<- c(warnings, conditionMessage(w))
+          invokeRestart("muffleWarning")
+        }
+      )
+      expect_equal("sess.plot" %in% getTaskCallbackNames(), !supported[i])
+      expect_length(warnings, if (backend == "httpgd" && !supported[i]) 1L else 0L)
+      if (length(warnings)) expect_true(grepl("httpgd >= 2.0.1", warnings, fixed = TRUE))
+      sess:::runtime_stop()
+    }
+  }
+})

src/helpViewer/cran.ts

@@ -1,7 +1,7 @@
 
 import * as cheerio from 'cheerio';
 import { Package} from './packages';
-import { getHttpText } from './http';
+import { getHttpText } from '../http';
 
 type ParseFunction = (html: string, baseUrl: string) => Package[];
 

src/helpViewer/helpProvider.ts

@@ -2,7 +2,7 @@ import { Memento, window } from 'vscode';
 import * as cp from 'child_process';
 
 import * as rHelp from '.';
-import { getHttpText } from './http';
+import { getHttpText } from '../http';
 import { extensionContext } from '../extension';
 import { catchAsError, config, DisposableProcess, getRLibPaths, spawn, spawnAsync } from '../util';