Add conda_capable, conda_capable functions

* Add struct CondaCapabilities

2 files changed, 108 insertions, 0 deletions

diff --git a/src/lib/core/conda.c b/src/lib/core/conda.c
index c9eb750..411f61a 100644
--- a/src/lib/core/conda.c
+++ b/src/lib/core/conda.c
@@ -691,3 +691,72 @@ int conda_env_exists(const char *root, const char *name) {
     snprintf(path, sizeof(path), "%s/envs/%s", root, name);
     return access(path, F_OK) == 0;
 }
+
+void conda_capable_free(struct CondaCapabilities *ccap) {
+    guard_free(ccap->conda_version);
+    guard_free(ccap->mamba_version);
+    memset(ccap, 0, sizeof(*ccap));
+}
+
+int conda_capable(struct CondaCapabilities *ccap) {
+    struct CondaCapabilities *cc = ccap;
+    memset(cc, 0, sizeof(*cc));
+
+    if (find_program("conda")) {
+        cc->available = true;
+    }
+
+    if (cc->available) {
+        int status = 0;
+        char *conda_version = shell_output("python3 -c 'import conda; print(conda._version.__version__)'", &status);
+        if (status) {
+            SYSERROR("conda version detection failed");
+            guard_free(conda_version);
+            return -1;
+        }
+        if (!conda_version) {
+            SYSERROR("unable to allocate conda_version_raw");
+            return -1;
+        }
+        strip(conda_version);
+
+        char *mamba_version = shell_output("python3 -c 'import libmambapy; print(libmambapy.version.__version__)'", &status);
+        if (status) {
+            SYSERROR("mamba version detection failed");
+            guard_free(conda_version);
+            guard_free(mamba_version);
+            return -1;
+        }
+        if (!mamba_version) {
+            SYSERROR("unable to allocate mamba_version");
+            guard_free(conda_version);
+            guard_free(mamba_version);
+            return -1;
+        }
+        strip(mamba_version);
+
+        cc->conda_version = strdup(conda_version);
+        cc->mamba_version = strdup(mamba_version);
+        if (version_compare(GT | EQ, cc->conda_version, "25.3.0")) {
+            cc->require_explicit_export_format = true;
+            cc->require_boa = false;
+        } else {
+            cc->require_explicit_export_format = false;
+            cc->require_manual_activation_shim = true;
+            cc->require_boa = true;
+            cc->require_libmamba_solver = true;
+        }
+
+        struct Process proc = {0};
+        safe_strncpy(proc.f_stderr, "/dev/null", sizeof(proc.f_stderr));
+        if (shell(&proc, "mamba install --use-local --dry-run conda")) {
+            cc->missing_use_local = true;
+        }
+
+        cc->usable = true;
+
+        guard_free(mamba_version);
+        guard_free(conda_version);
+    }
+    return 0;
+}
\ No newline at end of file
diff --git a/src/lib/core/include/conda.h b/src/lib/core/include/conda.h
index cc9426d..7a0023e 100644
--- a/src/lib/core/include/conda.h
+++ b/src/lib/core/include/conda.h
@@ -26,6 +26,45 @@
 #define PKG_INDEX_PROVIDES_E_MANAGER_EXEC (PKG_INDEX_PROVIDES_ERROR_MESSAGE_OFFSET + 5)
 #define PKG_INDEX_PROVIDES_FAILED(ECODE) ((ECODE) <= PKG_INDEX_PROVIDES_ERROR_MESSAGE_OFFSET)
 
+/**
+ * @struct CondaCapabilities
+ * @brief Collection of feature flags to support older, newer, and transitional versions of conda/mamba.
+ * @see implementation in `conda_capable`
+ */
+struct CondaCapabilities {
+    /// Currently installed version of Conda
+    char *conda_version;
+    /// Currently installed version of Mamba
+    char *mamba_version;
+    /// Is conda available in the runtime environment?
+    bool available;
+    /// Can conda execute?
+    bool usable;
+    /// Do we need to pass extra arguments to "conda env export"?
+    bool require_explicit_export_format;
+    /// Do we need to inject our own shim to make Conda available?
+    bool require_manual_activation_shim;
+    /// Does this version of Conda support building with boa?
+    bool require_boa;
+    /// Does this version of Conda need to be configured to use libmamba?
+    bool require_libmamba_solver;
+    /// Does "mamba install --use-local" work on this version of mamba?
+    bool missing_use_local;
+};
+
+/**
+ * Check for the existence of "Conda" and set flags based on the availability of features
+ * @param ccap a pointer to an empty `struct CondaCapabilities`
+ * @return 0 on success
+ */
+int conda_capable(struct CondaCapabilities *ccap);
+
+/**
+ * Free memory allocated by `conda_capable`
+ * @param ccap a pointer to a populated `struct CondaCapabilities`
+ */
+void conda_capable_free(struct CondaCapabilities *ccap);
+
 struct MicromambaInfo {
     char *micromamba_prefix;    //!< Path to write micromamba binary
     char *conda_prefix;         //!< Path to install conda base tree