Handle invalid conda-meta/history value

NEWS.md

@@ -7,6 +7,9 @@
 - Fixed segfault encountered in RStudio when rapidly switching 
   between R and Python chunks in a Quarto document (#1665).
 
+- Improved behavior when the conda binary used to create an environment
+  could not be resolved (contributed by @tl-hbk, #1654, #1659)
+
 # reticulate 1.39.0
 
 - Python background threads can now run in parallel with the R session (#1641).

R/conda.R

@@ -1106,9 +1106,16 @@ get_python_conda_info <- function(python) {
     else
       file.path(root, "bin/conda")
   } else {
-    # not base env, parse conda-meta history to find the conda binary
-    # that created it
-    conda <- python_info_condaenv_find(root)
+    # not base env
+    # in ArcGIS env, conda.exe lives in a parent directory
+    exe <- file.path(root, "../..", "Scripts", "conda.exe")
+    exe <- normalizePath(exe, winslash = "/", mustWork = FALSE)
+    if (is_windows() && file.exists(exe)) {
+      conda <- exe
+    } else {
+      # parse conda-meta history to find the conda binary that created it
+      conda <- conda_history_find(root)
+    }
   }
 
   conda <- normalizePath(conda, winslash = "/", mustWork = FALSE)
@@ -1123,6 +1130,37 @@ get_python_conda_info <- function(python) {
 }
 
 
+conda_history_find <- function(path) {
+  exe <- if (is_windows()) "conda.exe" else "conda"
+
+  # read history file
+  histpath <- file.path(path, "conda-meta/history")
+  if (!file.exists(histpath))
+    return(NULL)
+
+  history <- readLines(histpath, warn = FALSE)
+
+  # look for cmd line
+  pattern <- "^[[:space:]]*#[[:space:]]*cmd:[[:space:]]*"
+  lines <- grep(pattern, history, value = TRUE)
+  if (length(lines) == 0)
+    return(NULL)
+
+  # get path to conda script used
+  script <- sub(
+    "^#\\s+cmd: (.+?)\\s+(env\\s+create|create|rename)\\s+.*",
+    "\\1", lines[[1]], perl = TRUE
+  )
+  # on Windows, a wrapper script is recorded in the history,
+  # so instead attempt to find the real conda binary
+  if(is_windows())
+    conda <- file.path(dirname(script), exe)
+  else
+    conda <- script
+  normalizePath(conda, winslash = "/", mustWork = FALSE)
+
+}
+
 conda_prefix <- function(conda = "auto") {
   conda <- normalizePath(conda_binary(conda),
                          winslash = "/", mustWork = TRUE)

R/python-tools.R

@@ -144,7 +144,7 @@ python_info_condaenv <- function(path) {
   python <- file.path(path, suffix)
 
   # find path to conda associated with this env
-  conda <- python_info_condaenv_find(path)
+  conda <- get_python_conda_info(python)$conda
 
   list(
     python = python,
@@ -155,56 +155,6 @@ python_info_condaenv <- function(path) {
 
 }
 
-python_info_condaenv_find <- function(path) {
-
-  # first, check if we have a condabin
-  exe <- if (is_windows()) "conda.exe" else "conda"
-  conda <- file.path(path, "condabin", exe)
-  if (file.exists(conda))
-    return(conda)
-
-  if (is_windows()) {
-    # in Anaconda base env, conda.exe lives under Scripts
-    conda <- file.path(path, "Scripts", exe)
-    if (file.exists(conda))
-      return(conda)
-
-    # in ArcGIS env, conda.exe lives in a parent directory
-    conda <- file.path(path, "../..", "Scripts", exe)
-    conda <- normalizePath(conda, winslash = "/", mustWork = FALSE)
-    if (file.exists(conda))
-      return(conda)
-
-  }
-
-  # read history file
-  histpath <- file.path(path, "conda-meta/history")
-  if (!file.exists(histpath))
-    return(NULL)
-
-  history <- readLines(histpath, warn = FALSE)
-
-  # look for cmd line
-  pattern <- "^[[:space:]]*#[[:space:]]*cmd:[[:space:]]*"
-  lines <- grep(pattern, history, value = TRUE)
-  if (length(lines) == 0)
-    return(NULL)
-
-  # get path to conda script used
-  script <- sub(
-    "^#\\s+cmd: (.+?)\\s+(env\\s+create|create|rename)\\s+.*",
-    "\\1", lines[[1]], perl = TRUE
-  )
-  # on Windows, a wrapper script is recorded in the history,
-  # so instead attempt to find the real conda binary
-  if(is_windows())
-    conda <- file.path(dirname(script), exe)
-  else
-    conda <- script
-  normalizePath(conda, winslash = "/", mustWork = FALSE)
-
-}
-
 python_info_system <- function(path, python) {
 
   list(